Banebots RS-775 Case Short

[Tom Bottiglieri]

We have a Banebots 775 motor with its power leads shorted to the case. You can imagine why this would be an issue. We are not sure whether this is the one from the kit or the additional one we ordered.

I've seen one other team who posted about a problem with this... (http://blog.iamjvn.com/2011/02/jvn-build-tip-test-your-775-motors.html)

Is anyone else having this issue? If you have NOT run your 775's yet, could you check them and see if they have this problem? It would be nice to know if they are DOA or if they were damaged while running in the robot.

[Jeff Waegelin]

John mentioned it in his blog post, but we saw this on some brand new out-of-the box motors, too. It wasn't limited to just the ones we had already run.

[Karthik]

1114 has seen the same thing with some of our unused and used 775s.

[Mr. Lim]

On a semi-related note,

We've also run into an issue where the "red dot" that presumably indicates where the positive terminal of the motor is is not consistent between the RS-775s.

We have a single gearbox that mates to two RS-775s, and had them both wired according to the red dot, and when we powered them up, they ran in opposite directions...

[artdutra04]

25% of the unused, still-in-the-box 775 motors we tested were case shorted.

[AdamHeard]

Zero of our 15ish were defective, but not have been installed and ran on a robot.

[JDL]

Although we aren't using any on our bot I'm gonna check ours just for kicks.


Side note: it really is good practice to check all motors for such issues before you use them, prevents nasty little surprises sometimes. I never apply power to a new motor (in FIRST or otherwise) without testing it for ground faults and other problems.

[MattC9]

Hmmmm.... Just our luck I went and checked our 3, 2 of which were conductive. What exactly makes them "bad"? I have not heard why exactly this a problem.

[Trent B]

Got in 3 today crammed in a flat-rate box without much padding. None have case shorting issues.

[MrForbes]

Hmmmm.... Just our luck I went and checked our 3, 2 of which were conductive. What exactly makes them "bad"? I have not heard why exactly this a problem.

Imagine two of your motors have a short to the case, and they're mounted to metal parts of your robot that connect...interesting things might happen.

I think it's also against the rules to have any power applied to the metal parts of the robot.

<R36> All wiring and electrical devices, including all control system components, shall be electrically isolated from the ROBOT frame. The ROBOT frame must not be used to carry electrical current (e.g. this is necessary due to polarity reversals that occur under certain operating conditions such as during motor direction reversals).

[trilogy2826]

Arrgh... 3 of our 10 were shorted to case. Thanks for saving us some trouble. Has anyone tried to go through the Banebots RMA process yet?

[rsisk]

Could someone please post the steps to check the 775s for a short?

Is there a fix? Or do the motors need to be returned.

Thanks

[Mike8519]

3/7 of ours were shorted

[JVN]

Could someone please post the steps to check the 775s for a short?

Is there a fix? Or do the motors need to be returned.

Thanks

Use a multimeter to check the resistance between one of your motor leads and the motor casing. If it is conductive, you've got a problem.

We pulled one apart and tried to fix it, but no luck.

We haven't done the RMA process and probably won't bother (the motors have all been modified for use). The ordering (waiting) process was painful enough.

We had one of these motors (via AM Planetary) driving the same gear as a CIM. One of my freshman was wondering why the "gear was sparking." I told him it was normal to see sparks coming out the back of an open motor like the 775. He corrected me -- "not out the back, on the front... on the gear." Ugh -- that was when we first noticed the issue.

-John

[IndySam]

We had one of these motors (via AM Planetary) driving the same gear as a CIM. One of my freshman was wondering why the "gear was sparking." I told him it was normal to see sparks coming out the back of an open motor like the 775. He corrected me -- "not out the back, on the front... on the gear." Ugh -- that was when we first noticed the issue.

-John

You gotta love those young eyes!

[Dad1279]

We were lucky for once. 1 out of 6 bad, but it was a spare.

We also have one with the screw threaded slightly out of square, when mounted in a Cim-U-later, it binds the motor.

[Nick Lawrence]

So far, no problems for us.

-Nick

[dyanoshak]

I just got off the phone with BaneBots.

They believe the problem is caused by a small amount of debris in the motor possibly introduced during manufacturing.

They have had success with several motors in house when they apply 12V between the motor lead and the case. This zaps the debris and you should be good to go. You might have try this with both leads depending on where the debris is.

I will try this on our 2 shorted motors tonight and post our results.

-David

[Tom Bottiglieri]

I just got off the phone with BaneBots.

They believe the problem is caused by a small amount of debris in the motor possibly introduced during manufacturing.

They have had success with several motors in house when they apply 12V between the motor lead and the case. This zaps the debris and you should be good to go. You might have try this with both leads depending on where the debris is.

I will try this on our 2 shorted motors tonight and post our results.

-David
Thanks for the info. I'll give this a go as well and post the results.

[billbo911]

I just got off the phone with BaneBots.

They believe the problem is caused by a small amount of debris in the motor possibly introduced during manufacturing.

They have had success with several motors in house when they apply 12V between the motor lead and the case. This zaps the debris and you should be good to go. You might have try this with both leads depending on where the debris is.

I will try this on our 2 shorted motors tonight and post our results.

-David

Would it be legal to open the motors for the purpose of cleaning them as long as they were not modified in any way?

I know it would be a difficult task, and might end up damaging the motors, but applying 12vdc across a known short is not what I would consider a safe option let alone a good fix. More debris could still be in the motor, and the frag from blasting the original offender is still in there and becomes a complete unknown. It would be like asking Murphy pay a visit at the worst possible moment.

[Manoel]

Would it be legal to open the motors for the purpose of cleaning them as long as they were not modified in any way?

I know it would be a difficult task, and might end up damaging the motors, but applying 12vdc across a known short is not what I would consider a safe option let alone a good fix. More debris could still be in the motor, and the frag from blasting the original offender is still in there and becomes a complete unknown. It would be like asking Murphy pay a visit at the worst possible moment.

I agree it's not the safest option, but you could always try shorting it with a source that does NOT easily supply 500 A...

[dyanoshak]

I agree, this "fix" makes me a little uneasy. I am just repeating what they suggested.

I figure since our shorted motors are useless anyway, it is worth a shot. BaneBots told me to give them a call if the "fix" doesn't work or there are more problems.

I would try this with a smaller battery or a current limiting power supply. They told me that it should only take a few milliamps to zap the debris/residue (at one point the BaneBots rep mentioned "manufacturing residue").

-David

[Al Skierkiewicz]

David,
I just think this method is bad on so many levels. Did they give you any idea on what form of debris may be present that they are trying to zap? If this is metal flakes left over from balancing operations, shorts to case are going to be the least of the problems. Depending on the size of the debris, this may be a permanent fix or a permanent short.I won't have access to a motor for a while, can you examine one of yours?

[Brandon Holley]

If someone does attempt the zap, report back on your findings ASAP, I know a few teams who would be interested to know if this "fixes" the motors or not.

-Brando

[Tom Bottiglieri]

I agree, this "fix" makes me a little uneasy. I am just repeating what they suggested.

I figure since our shorted motors are useless anyway, it is worth a shot. BaneBots told me to give them a call if the "fix" doesn't work or there are more problems.

I would try this with a smaller battery or a current limiting power supply. They told me that it should only take a few milliamps to zap the debris/residue (at one point the BaneBots rep mentioned "manufacturing residue").

-David
I gave both leads about 100mA through the case for about 3 minutes each. Nothing. I'm debating if a big burst (like, say, a battery) is worth trying. I can't really imagine it is.

[Hilda]

Team 85 gave the BaneBot suggestion a try to rectify the issue with the 775 motor and we are good to go!

[EricVanWyk]

Team 85 gave the BaneBot suggestion a try to rectify the issue with the 775 motor and we are good to go!

Could you check the continuity again after using it while slowly turning the shaft by hand? I'm wondering if it is an intermittent short.

[Hilda]

Could you check the continuity again after using it while slowly turning the shaft by hand? I'm wondering if it is an intermittent short.

Did what you asked and we are still good to go

[MattC9]

Would it be legal to open the motors for the purpose of cleaning them as long as they were not modified in any way?


Well <r47> states

<R47> Motors and servos used on the ROBOT shall not be modified in any way, except as follows:
A. The mounting brackets and/or output shaft/interface of the motors may be modified to
facilitate the physical connection of the motor to the ROBOT and actuated part.
B. The electrical input leads on the motors may be trimmed to length as necessary.
C. The locking pins on the window motors may be removed.
D. The connector housings on the Window motors (PN 262100-3030 and 262100-3040) may
be modified to facilitate lead connections.

I would take that as a "no" just to be on the safe side.

[Adam Freeman]

~50% of our motors (atleast 7) had the Case Short.

We performed the technique suggested by Banebot, with a standard FIRST battery, and "fixed" the issue on our motors.

I wasn't involved in the process, but I think they just swiped the positive lead across the motor case to limit any additional damage. It took a couple of swipes to totally eliminate the short.

Not sure what the long lasting effects will be.... we plan to run these motors on our practice bot to see how well they work.

We are only using (2) RS775 on the our robot, and I think we had (4) good ones...so those will go on the competition robot.

[Jared Russell]

We were 3/3 with the "zapping" technique. We had to do it a couple of times to max out our ohmmeter on a couple of motors. We rotated the shafts by hand both while "zapping" and while verifying the open circuit.

[Tom Line]

I'm sorry, but working or not this is an extremely bad suggestion. What if that small bit of 'residue' is actually a sizeable chunk of metal? You can potentially spot weld the battery leads to the motor and cause someone serious injury. I've seen this happen when someone tried something similar with a fan.

We'll try something tomorrow, but we'll do it through a 40 amp snap action and see if we have any luck with that.

I will also add that this will likely be the swan song for the use of banebots hardware for our team (unless we're forced into it by FIRST continuing to use their motors). After '07, the transmissions, and now incredibly poor quality control on their motors, we've had enough.

We have enough build season issues without having to RMA things we've bought and redesign major components because of a lack of timely shipping.

[Al Skierkiewicz]

Adam,
Was there fireworks when you applied the battery? Please note that TU11 was released tonight that modifies the 'do not modify' rule.

[Adam Freeman]

Adam,
Was there fireworks when you applied the battery? Please note that TU11 was released tonight that modifies the 'do not modify' rule.

Al,

I was working on another part at that time, but from what I saw there were no fireworks. It actually appeared "easy" to do....but I am sure they were taking precautions to attempt to limit the risks.

I do agree with Tom Line, its not the smarted thing to do...and that there are potentially some really bad things that could happen.

I would advise that people attempt to do this at their own risk.

Hopefully we can come up with a safer way to "fix" these motors.

[Jared Russell]

There were no fireworks when we tried this. For motor #1, there was a very quiet "pop" sound at first, then nothing. For motor #2, there was a bit of an arc when the motor lead was attached, then nothing. For motor #3, there was no visible or audible reaction at all. The suggestion to use a 40A breaker is a good one.

2 of the 3 775s on our first robot were affected by the case short. Prior to doing the "zapping", we were measuring ~8 megaohms between the negative battery lead and conductive parts of our chassis. After removing each affected motor and applying the fix, we now max out the ohmmeter (>30 megaohm resistance).

[Mike9966]

Hi all,
I checked our 3 motors last night and found 2 of them to be shorted, if you call 6 ohms shorted.
I set up a smaller battery, and a 40A breaker and proceeded to 'zap' them by putting one wire on the terminal and one on the housing.
One motor showed no sign of a spark and was healed and works fine now, and the other one showed a bigger spark on the first touch, but no sparks on subsequent tries, unfortunately, it was only semi healed in that it continues to have 300-500 ohms of case to terminal resistance.

While I'm happy to get one motor working, I have to say that this is the craziest fix, and I'm not happy with having to have done it.

If you try it, please be safe.

Mike

[Al Skierkiewicz]

Has anyone be able to see the debris? Can you describe it? What I am trying to determine is this a permanent fix or is there more of the debris just waiting to bite us in competition. We need a permanent and reliable solution.
For others, a 10K or higher resistance any lead to case seems to be OK, megohm is better. The six ohms reported is definitely bad, 500-600 ohms is still in the bad region as well.

[Jared Russell]

I did not see any debris before, during, or after the zapping. I will continue to monitor for case shorts as we continue to do testing and driving.

BTW, although in my prior post I mention 8 megaohm resistance to the frame (from negative battery terminal to the furthest point of our arm), resistance between the motor terminals and the motor case itself was below 1 ohm prior to the zapping (now it is >30 megaohms).

[Jim Wilks]

We had 2 of 5 motors with case shorts. One was 1k ohm and the other was about 2 ohms. We applied 12VDC from a current limited power supply set for 25A max. On the 1k ohm motor, the problem cleared immediately. The 2 ohm motor let loose with some nice blue sparks, but then was good.

We remeasured both motors and both still had some high resistance (~20K ohms) to ground. We than ran each motor for a few minutes while applying + to the case. We then repeated this with - to the case. Both motors are now showing >20M ohms. I guess that's a fix!

No debris was seen at any point in the proceedings.

However, I must echo the points above about being careful when doing this as a short which does not clear could be very dangerous, particularly if your voltage is not current limited to a "safe" level.

Banebots has really "missed the boat" on this years offerings to FIRST.

JW

[JesseK]

Thanks for all of the info -- we'll get our extra 775's in after ship date, so we'll have to test things then. The KOP 775 was fine though.

This makes me weary of BB. We didn't have the problems in 2007 that others had (custom plates), yet between this and our eaten 256:1 gearbox in 2008 I think we'll take pause on our gut reactions to use the BB motors in future years.

[dyanoshak]

It seems like our attempt at the zap was successful on one motor. We still have one other motor to try later tonight.

I ran the motor for some time and it is still operating as it should. Before the zap, 4 ohms, after the zap, open circuit.

-David

[Al Skierkiewicz]

Everyone,
I am attempting to find the type of debris that teams may encounter and where it might be located in your motors so I can pass this info to inspectors. Believe it or not, some teams don't visit CD for the latest discussions. Electrically neutral frames are a line item for inspections that will need to be dealt with during the season. Thanks for everyone's help on this issue.

[Tom Line]

I was not able to see any debris in the motors we fixed today.

However, one was a little more 'substantial' than the other, we got sparks about 12 inches out the front of the motor and the negative lead spot welded itself to the motor case.

The motor does appear to be fixed though. We got a nice round of 'oooooooooooo' from the audience when we did it too. ::safety::

[Al Skierkiewicz]

Tom,
That was more the effect I was worried about. From the angle of the trajectory would you say that the flames came from the end of the motor (brush assy) or from the commutator? I am guessing that is the only two places where debris would collect and still short to frame. Or could it be excess solder where the windings are tied to the commutator?

[Tom Line]

Tom,
That was more the effect I was worried about. From the angle of the trajectory would you say that the flames came from the end of the motor (brush assy) or from the commutator? I am guessing that is the only two places where debris would collect and still short to frame. Or could it be excess solder where the windings are tied to the commutator?

Actually, if I were to guess I'd say neither. The sparks actually exited the front of the motor through the holes that surround the axle. Had this been a short near the brushes or commutators, I would have expected them to come out the back (where I had my hands...).

That doesn't make much sense to me, because I'd expect the wire to be covered in varnish and not be conductive except at the locations you mentioned.

[Al Skierkiewicz]

OK,
Now I am really confused. I haven't taken a 775 apart. I wonder if there is winding terminations at both ends of the armature.

[ChuckDickerson]

For what it's worth, 3 of our 8 775s had a short to case. I had marked them as "bad" and was going to pitch them in the trash. After reading here about the zaping procedure I figured what the heck and gave it a try. The zaping procedure seemed to fix all three of our motors, however, we will still not be using them in competition and are considering not using any 775s at all and changing our plan to use 550s and the FP. I am pretty disappointed in BaneBots over the years and this just adds insult to injury. :mad:

Of the 3:

The first 2 sparked somewhat spectacularly both apparently from the larger holes near the back/terminal end.

The last 1 produced almost no spark at all and was only visable as a tiny (~1/16") arc when the wire touched the case. No sparks apparent coming from inside the motor.

The first one we zapped with the lights on and sparks were clearly visable even in a well lit area. For "effect" we cut the lights off on the last 2 and the first one sparked nicely and the last one was the one with almost no spark which probably wouldn't have even been visable if the lights were on. On all three it only took one zap to fix the motor. The procedure was about as simple as it gets. I took a robot battery plugged in an Anderson connector with bare wires, held the red to the red terminal on the motor and touched the black to the case. No breaker involved. For as strange of a "recomended fix" as this is it seemed to work. The second motor we did does have a slight burned black line on the case where the wire touched. Other than that no other obvious signs on the outside other than where I wrote on them with a Sharpie.

[Ether]

The procedure was about as simple as it gets. I took a robot battery plugged in an Anderson connector with bare wires, held the red to the red terminal on the motor and touched the black to the case.

You left out the most important step:

I checked to make sure everyone in the room was wearing their safety glasses.

[ChuckDickerson]

You left out the most important step:

I checked to make sure everyone in the room was wearing their safety glasses.




Yeah, and we made sure there were no flamable liquids ar vapors nearby as well. ::safety::

[sanddrag]

I'm super curious as to what exactly is shorted in the first place, and is blowing apart inside during this procedure. Can someone who has some 775 spares sacrafice one for curiosity's sake?

[Nick Lawrence]

2 of our 6 RS-775s had case shorts as well. We tried the case-to-lead zapping procedure recommended by BaneBots, and it remedied the problem on both. We did have to zap one of them twice after we spun it a few times after the first attempt. I wish there was a safer way to fix this without taking them apart.

-Nick

[MrForbes]

I keep forgetting to measure ours, we just have the one that came in the kit. If it's shorted, I'll take it apart. If I remember. We happen to be kind of busy building a robot, so I'm sort of distracted when I'm at the school.

[falconmaster]

We just two more yesterday and checked them. They are both good! We have to earlier and they are good two.. I guess we got lucky

[Chris is me]

Our kit motor and one of the three we ordered had the case short. Luckily the decision was made to use a Window motor on our arm instead. The other two motors were installed on CIMulators and will be put on our drivetrain once we find some CIM keys...

I'm really hesitant to do the battery pulse fix on these motors. We'll see.

[Al Skierkiewicz]

Hey Jim, You have used that excuse in the past.

[MrForbes]

Thanks for reminding me to make a reminder for myself....hopefully I'll see it when I write some other reminder on my hand today.

[Al Skierkiewicz]

Ah, the signs of spring are in the air, preship craziness. I am off to playing field and shop for a day of fun and fluorescent light.

[MrForbes]

We got lucky, our kit 775 has less than two ohms resistance between the case and terminals. Good thing we didn't try to use it. We did not try to clear the debris with the battery trick, but did take it apart, and aside from slightly chipping the brushes while removing the end cap, did not see any debris. The windings are almost a dead short to the motor shaft (measured between shaft and commutator). Any suggestions for what to do now? Maybe we could unwind the windings? the soldering job doesn't look very good, but it also doesn't look like it would be causing problems. I took some pics but don't have means to get the pics off my camera here at school.

[sandiegodan]

I pulled our Banebot 775 apart before I read about the fix. The connection to the case is through the rotor assembly to the rotor shaft. A direct short can be read between the commutator and the shaft.

There is no obvious debris. I could speculate what happens during the "manufacturing process," but until Banebots is more forthcoming with specifics, I don't think we will really know. The rotor assembly is pressed then varnished, without extensive forensics, I would say the exact problem will be hard to get at. There are some balance holes machined out of the stack, so maybe that is the source of the issue.

After I reassembled, I applied the battery current across the terminal and case. There was a minor spark and now the motor is fine. We can't use it in competition since it has been disassembled, but it will be perfectly acceptable for practice.

If anyone knows if Banebots is replacing these it would be nice to know.

Dan Glenn
Mentor
Team 1622 Spyder, Poway High School, California

[MrForbes]

picture of armature.

[MrForbes]

Using a better ohm meter, although the test leads themselves have a bit of resistance (about 0.1 ohms when shorted).

[Ether]

Hey Jim,

That is one fine voltmeter ya got there. Have you tried getting it assessed on Antiques Roadshow?


Oh, BTW: I think the calibration date is a bit overdue :-)

[MrForbes]

I was just noticing that it was last calibrated when our youngest sons (twins) were still a twinkle in my eye...and they're in college now....

[Andrew Bates]

If anyone knows if Banebots is replacing these it would be nice to know.

Dan Glenn
Mentor
Team 1622 Spyder, Poway High School, California

We got a response when we sent in an RMA request that this was a known issue and that they would not replace the motor. They simply said to apply some voltage across the case and a motor lead to burn off the manufacturing debris.

[Dad1279]

We got a response when we sent in an RMA request that this was a known issue and that they would not replace the motor. They simply said to apply some voltage across the case and a motor lead to burn off the manufacturing debris.

Same here: "If it is an issue for your application it can easily be eliminated by passing a modest amount of current from the terminal to the case."

As far as I'm concerned, this is not a FIRST legal motor if it conducts current to ground. Worst customer support of any FIRST KOP supplier. I hope First thinks twice before using these motors in KOP again.

[Danny Diaz]

Our kit 775 also had 2.3 Ohms between terminal and the case on BOTH terminals, and we'd been using it off and on for a few days. We shorted the terminals to the case with the battery (one at a time) and now we're seeing 126kOhm between terminal and case on both terminals. Our other 775 that we were "gifted" from 3320 (The M&M's) had 3MOhm between terminals and case.

I was disappointed that there wasn't as much of a fireworks display as others seem to have experienced when we did it. :o

-Danny

[sanddrag]

Worst customer support of any FIRST KOP supplier. I hope First thinks twice before using these motors in KOP again.Show me where else you can get these motors and decent planetary gearboxes for them at the same price. If you want great support behind the products, would you also want to pay double the price for them, so they could hire more people to support them? I'm sure they probably are not a large company. Yes, they've had long lead times and a few issues, but give them a break. We could be using Bosch drill transmissions... You know back around 2002, there was no BaneBots, there was no AndyMark, there were no CIM motors with a nice keyed shaft, and we were restricted to purchasing parts only from one very overpriced supplier. Teams still made great robots.

Yes, the BaneBots products have a few flaws. But, it's up to the designer to consider those shortfalls, and design around them. For the price, their products are great. I was quite happy to see the BaneBots motors (especially the 775) in the KOP this year, and I hope they are here to stay.

[Chris is me]

With the exception of this large design flaw, the 775-18v is a great motor that I hope we get to use again and again. The decision to include the 18v version and to run that at 12 volts was really smart!

[Ether]

With the exception of this large design flaw,

We don't know yet whether it is a design flaw or a manufacturing (quality control) problem.

[sandiegodan]

We don't know yet whether it is a design flaw or a manufacturing (quality control) problem.

I think we do know that it is a manufacturing problem:

I just got off the phone with BaneBots.

They believe the problem is caused by a small amount of debris in the motor possibly introduced during manufacturing.

They have had success with several motors in house when they apply 12V between the motor lead and the case. This zaps the debris and you should be good to go. You might have try this with both leads depending on where the debris is.

I will try this on our 2 shorted motors tonight and post our results.

-David

If you do execute the fix, the motors are fine. Our problem is, we opened them up before we read about the fix, now we are left to buy new ones or design around the motors.

Dan Glenn
Mentor, Team Spyder 1622
San Diego, CA

[Ether]

I think we do know that it is a manufacturing problem:


Originally Posted by dyanoshak
I just got off the phone with BaneBots.

They believe the problem is caused by a small amount of debris in the motor possibly introduced during manufacturing.

I guess my point was this: Just because the debris is introduced during manufacturing doesn't necessarily mean it is a manufacturing problem.

If the design is such that no reasonable (cost effective) manufacturing process would be capable of avoiding unacceptable debris, then it is a design problem.

[MrForbes]

The insides look like countless other motors....but without seeing the complete design documentation, and seeing what the actual problem is, it's guesswork. My guesswork says manufacturing problem, either with the process or materials not meeting spec.

I should unwind the thing and see if there's really any debris, or if the insulation on the wire is damaged. Although it's probably gonna be hard to tell.

[MrForbes]

I cut all the windings at the commutator connections. The first winding (there are 5, overlapping) is the one that is shorted. So I guess I'll take them all off and see what I can find.

[MrForbes]

I found the short. The first winding on the motor was touching the amature core, at this corner. I found it by connecting my trusty 77 DMM to one end of the wire and to the shaft, and it beeped until I got this part of the winding loose. It was very difficult to remove the wire here. As soon as I pulled it loose, the beeping stopped.

My take on it: I did not find any "debris" in this motor, but it also had a complete short of winding to armature core. If you have a completely shorted motor (less than 5 ohms resistance from either terminal to case), then I'd suggest you do not use that motor. If the resistance is considerably higher, then you might possibly have a "debris" problem, and if you "fix" it by blowing it with high current from case to winding, the motor might be fine.

btw the white stuff is glue that is used to hold the plastic fan in place.

I hope this little forensic exercise was helpful!

[billbo911]

I found the short. The first winding on the motor was touching the amature core, at this corner. I found it by connecting my trusty 77 DMM to one end of the wire and to the shaft, and it beeped until I got this part of the winding loose. It was very difficult to remove the wire here. As soon as I pulled it loose, the beeping stopped.

My take on it: I did not find any "debris" in this motor, but it also had a complete short of winding to armature core. If you have a completely shorted motor (less than 5 ohms resistance from either terminal to case), then I'd suggest you do not use that motor. If the resistance is considerably higher, then you might possibly have a "debris" problem, and if you "fix" it by blowing it with high current from case to winding, the motor might be fine.

btw the white stuff is glue that is used to hold the plastic fan in place.

I hope this little forensic exercise was helpful!

First off, Jim, thank you for taking the time to look into this issue in such detail and giving us this information.

Here is my concern based on what you found:

If this is in fact the root cause, and common to all the 775 motors showing this fault, then the "fix" is only truly is a poor solution.

Here is why I say that. For the "fix" to work, the current path has to be through the terminal(s), through one of the brushes into the commutator, through the short and into the armature then finally through the bushings/bearings to the case. The current that can possibly blow this short open, also has the potential to damage the brush/commutator contact point as well as the bushing/bearing assembly. Yes, the brush/commutator are designed to carry high current, but the bushings/bearings are not. (I use the term "bushing/bearings" because I am not sure of exactly how this motor is actually assembled.)
Now, if enough current is passed to open this short, then I can almost assure you that it not passing through the bushing/bearings without having a detrimental effect. How much damage is being done is indeterminable at this point. How long will these motors run without failing is also an unknown.

I for one would rather replace the motor with a "known good" one, than risk it failing at the most inopportune time.

[MrForbes]

You're welcome.

The motor uses oilite type bushings, it looks like they're plenty large enough to conduct a lot of current without damage. I'd be more concerned about the brushes and commutator than the bushings. But I would be even more concerned that "fixing" a shorted winding will melt the wire and open it, so the motor will only be running on 80% of it's windings.

I looked closer at the armature, and I think the issue is that the wire was making contact at a corner of the winding, where it wraps around the core. The green insulating paint is deformed where some of the windings contact it at the corner, and in one spot metal was showing. I think that either the paint was not fully dry, or the wire was pulled too tightly as it was wound on the core.

I've enjoyed taking stuff apart ever since I was a little kid. I think it's part of the engineer mentality.

[Tristan Lall]

But I would be even more concerned that "fixing" a shorted winding will melt the wire and open it, so the motor will only be running on 80% of it's windings.This is worth a test.

And if it comes back that that's how the fix works—by severing a winding—then BaneBots should damned well have disclosed that fact. (Not knowing is negligence, not an excuse. I want to give them the benefit of the doubt: maybe their supplier was lying to them about the presence of debris, or maybe this one motor is not representative of the failure mode that they'd encountered. But if BaneBots came up with the fix, it's their responsibility to explain the issue and resolution accurately and completely.)

I don't know the nature of BaneBots supplier arrangement with FIRST;* if they're donating the parts for free, or heavily discounting them, then I understand that we shouldn't ask too much of them. But if FIRST is a paying customer, I think that it would be reasonable to forward BaneBots a summary of the motor rules, with the explanation that all FRC teams are very strictly limited as to what they can and can't do, and that if BaneBots wants to do business, they need to provide somewhat better service. (Aside: actually, I support the idea of being able to repair parts in principle, so the recent team update was a good result. There are too many high-value or high-lead-time items that can fail and seriously disadvantage a team. As long as it's clear the repairs don't rise to the level of a significant functional change, I'm on board.)

This is not to minimize the impact of the corrective actions BaneBots has taken in the past with regard to their products—I'm sure that resolving those issues was stressful and complicated, not to mention costly. But the fundamental flaw those times was misspecification: for example, they hadn't provided accurate information on how to safely use the gearboxes. (Granted, in the case of the bad CIM boxes, if they'd done so, they wouldn't have sold any for drivetrains, because they would have had to publish specs indicating their parts were unlikely to be up to that task.)

In fact, let's consider the problems associated with BaneBots products in FRC applications (am I missing or mischaracterizing anything?):

2007: Failures reported on BaneBots high-reduction planetary gearboxes (36 mm (http://www.chiefdelphi.com/forums/showthread.php?t=52896) & 42 mm (http://www.chiefdelphi.com/forums/showthread.php?t=53010) sizes); BaneBots has since updated their specifications to warn against high-torque load cases, and released new lines of gearboxes that are apparently more durable
2007: BaneBots CIM gearboxes with defective planet carrier plates (http://www.chiefdelphi.com/forums/showthread.php?threadid=53007); BaneBots designed replacement (more durable) carriers
2009: Without advising purchasers, BaneBots substituted RS-545/RS-385 motors that didn't match the ones depicted on their website (listed as FIRST-legal), and more importantly, were different from the RS545PH-5125F model in the KOP; never explicitly resolved, but hopefully never happens again (we never found out what the specs on the plastic-endcapped RS-545 motors were)
2011: RS-775 motors are frequently defective as supplied
2011: Lead times of up to 3 weeks on some gearboxes
So what's the root cause here? Want to bet that it has something to do with not testing their products adequately for FRC applications? And maybe there's some unfamiliarity with just what they're being asked to provide, as an FRC supplier—e.g. have enough stock of the right motors (or be able to get them fast), and communicate with FRC HQ when your supply chain breaks down (instead of trying to pass off non-compliant materiel, or delaying shipments). (It's possible that FRC HQ hasn't communicated these expectations, perhaps because they see things differently; if that's the case, I'm interested in their position on the matter.)

Part of being in business is managing inventory and deliveries—and while it's a company's prerogative to choose to keep low inventory and impose long lead times, it's their customers' prerogative to not choose that company the next time they have a critical project. Similarly, while their low prices are great, I'm certain that the majority of FIRST teams are willing to concede that a little extra cost to ensure quality in a critical component like a motor or gearbox is a good thing. After all, isn't that a big reason why AndyMark products are so popular, despite their often-higher prices? (Along with excellent service and innate familiarity with FRC.) Isn't that why people will pay $25 to $28 for a CIM motor that virtually never fails?

Maybe BaneBots needs to concentrate on being a little more like AndyMark or IFI, or else consider taking a step back from their current role as a critical FRC supplier?

*Why don't I know this? Is there really any harm in disclosing this fact? After all, the benefit of disclosure is that it calibrates the community's expectations.

[Jack Jones]

Show me where else you can get these motors and decent planetary gearboxes for them at the same price. If you want great support behind the products, would you also want to pay double the price for them, so they could hire more people to support them? I'm sure they probably are not a large company. Yes, they've had long lead times and a few issues, but give them a break. We could be using Bosch drill transmissions... You know back around 2002, there was no BaneBots, there was no AndyMark, there were no CIM motors with a nice keyed shaft, and we were restricted to purchasing parts only from one very overpriced supplier. Teams still made great robots.

Yes, the BaneBots products have a few flaws. But, it's up to the designer to consider those shortfalls, and design around them. For the price, their products are great. I was quite happy to see the BaneBots motors (especially the 775) in the KOP this year, and I hope they are here to stay.

Another bright side: They don't sell airplanes :-/

BTW - the one's we used the ZAP fix on do not perform as well as the ones that tested OK. Anyone else notice a performance hit?

[Adam Freeman]

Another bright side: They don't sell airplanes :-/

BTW - the one's we used the ZAP fix on do not perform as well as the ones that tested OK. Anyone else notice a performance hit?


Yes, our programmers have commented on that fact as well.

[Ether]

the one's we used the ZAP fix on do not perform as well as the ones that tested OK. Anyone else notice a performance hit?

Yes, our programmers have commented on that fact as well.

Do you have any quantitative data, or is this mostly a perception ?

[Ether]

I would be even more concerned that "fixing" a shorted winding will melt the wire and open it, so the motor will only be running on 80% of it's windings.

Is there anyone who has access to a function generator or an oscilloscope who would be willing to test the locked-rotor inductance (and resistance) of a few "fixed" and non-defective RS775's ?

http://www.chiefdelphi.com/forums/showthread.php?t=90246

[MrForbes]

A picture of what I suspect is the problem with the motor I disassembled.

Notice the "dents" in the green insulating paint at the corner of the armature core, where the wire wraps around it. There are two places where the metal is showing through. The wire is insulated with a thin coat of some type of paint also (in the old days, it was varnish, I don't know what these ones use). It doesn't take much to scrape the insulation off the wire, and have it short.

[Al Skierkiewicz]

Jim,
Thanks for all the CIS on this motor. As Jack pointed out, my next question (assuming all of the motors have a winding to core short) is does the fix burn open one of the winding? In his case it seems as if it does. In your original photo, I also noticed a solder blob buried in the windings. That is a pretty bad job no matter what. Every student on my electrical team can do a better job than that.

[MrForbes]

Al, I expect that motors with a low resistance short have the problem I encountered, and it's likely that applying a lot of current will melt a wire. But I have no idea if there are other things wrong with other motors. I only had one to take apart. There are a lot of things that can go wrong when building an electric motor within strict cost constraints.

[JB987]

2 out of 3 bad for us...any chance the company actually tests their motors before they ship them out now??? Not comfortable with the "fix" if it reduces the performance as has been seen with some cases.

[Jack Jones]

2 out of 3 bad for us...any chance the company actually tests their motors before they ship them out now??? Not comfortable with the "fix" if it reduces the performance as has been seen with some cases.

IDK - Why test? They don't care what they sell us. I ordered two for spares and specifically asked for two that tested infinite resistance between leads and case. They sent two that tested 56k and 32k.

I will NEVER do business with them again!!

[Mike Betts]

IDK - Why test? They don't care what they sell us. I ordered two for spares and specifically asked for two that tested infinite resistance between leads and case. They sent two that tested 56k and 32k.

I will NEVER do business with them again!!

Jack, et al,

There is not a motor in the world which will pass that criteria.

Most of us spec out motors to a specific criteria form a recognized approval agengy (such as UL) called a Dielectric Withstand Test. The parameters for such a test would be that the device withstand a voltage (such as 2 times the rated maximum voltage plus 1000V) with less than a specified current (such as 1 mA) for a specified time (such as at least 60 seconds).

But we aren't buying UL listed motors, are we? We are using motors that are factory seconds or discontinued items that have been donated (or sold at a deep discount) to FIRST.

I'm not defending Banebots. This case shorting issue is not acceptable. However, you get what you pay for.

BTW, please check with your electrical lead mentor before attempting a DWT as you need specific test equipment and the test degrades the insulation being tested.

JMHO,

Mike

[JB987]

Jack, et al,

There is not a motor in the world which will pass that criteria.

Most of us spec out motors to a specific criteria form a recognized approval agengy (such as UL) called a Dielectric Withstand Test. The parameters for such a test would be that the device withstand a voltage (such as 2 times the rated maximum voltage plus 1000V) with less than a specified current (such as 1 mA) for a specified time (such as at least 60 seconds).

But we aren't buying UL listed motors, are we? We are using motors that are factory seconds or discontinued items that have been donated (or sold at a deep discount) to FIRST.

I'm not defending Banebots. This case shorting issue is not acceptable. However, you get what you pay for.

BTW, please check with your electrical lead mentor before attempting a DWT as you need specific test equipment and the test degrades the insulation being tested.

JMHO,

Mike

I realize you get what you pay for. The problem is we really have no choice when FIRST limits the brand/model and number of motors and the brand with the most choices has such poor quality product. We don't mind paying more for better product...just wish we had the choice to do so.

[Joe Ross]

I realize you get what you pay for. The problem is we really have no choice when FIRST limits the brand/model and number of motors and the brand with the most choices has such poor quality product. We don't mind paying more for better product...just wish we had the choice to do so.

Just as long as paying more doesn't involve $30 tetrix motors that are even worse...

[theprgramerdude]

Jack, et al,

There is not a motor in the world which will pass that criteria.

Most of us spec out motors to a specific criteria form a recognized approval agengy (such as UL) called a Dielectric Withstand Test. The parameters for such a test would be that the device withstand a voltage (such as 2 times the rated maximum voltage plus 1000V) with less than a specified current (such as 1 mA) for a specified time (such as at least 60 seconds).

But we aren't buying UL listed motors, are we? We are using motors that are factory seconds or discontinued items that have been donated (or sold at a deep discount) to FIRST.

I'm not defending Banebots. This case shorting issue is not acceptable. However, you get what you pay for.

BTW, please check with your electrical lead mentor before attempting a DWT as you need specific test equipment and the test degrades the insulation being tested.

JMHO,

Mike

Well, we paid $5000+++ to enter a competition that limits us on what we use to certain items. I'd prefer it if those items weren't faulty. Just sayin'

[Mike Betts]

I realize you get what you pay for. The problem is we really have no choice when FIRST limits the brand/model and number of motors and the brand with the most choices has such poor quality product. We don't mind paying more for better product...just wish we had the choice to do so.

I agree... I'm not defending FIRST. I'm pointing out reality (as I see it).

I've been doing this for 17 years now... FIRST has always limited "the brand/model and number of motors" and I see absolutely nothing in the tea leaves predicting a change.;

[Mike Betts]

Well, we paid $5000+++ to enter a competition that limits us on what we use to certain items. I'd prefer it if those items weren't faulty. Just sayin'

And in my opinion, you paid about $4000 too much...

[Jared Russell]

Just a warning...

Both RS-775 motors that we used on our competition bot that had been "fixed" by zapping became "unfixed" by the end of the first day of qualification rounds - the case shorts returned.

[Swampdude]

Just a warning...

Both RS-775 motors that we used on our competition bot that had been "fixed" by zapping became "unfixed" by the end of the first day of qualification rounds - the case shorts returned.

Is that what was disabling daisy?

[Jared Russell]

Is that what was disabling daisy?

The jury is still out - we pulled off anything we suspected before crating and will be doing CSI-style forensics in the coming days and weeks to get this fixed in time for Philly...

[chris1592]

Not related to a case short, but some of our 775 gearboxes for our arm motors were starting to tear up at Florida. The casing on it would start to rotate around the gears and this was tearing the inner gears up, has anyone else had this problem or had a solution to it?

We tried using hose clamps, but they only stop it from rotating so far.

The black pins that hold it from rotating would just pull out or shear off.

[Karthik]

The jury is still out - we pulled off anything we suspected before crating and will be doing CSI-style forensics in the coming days and weeks to get this fixed in time for Philly...

Jared,

I would not be surprised if the RS-775 case shorts were causing your robot to die. We have had an endless stream of issues arising from these motors. Every single motor we have ordered from Banebots has come with or developed a case short. (Some of the motors were not tested until we had already used them. It's not our standard operating practice to test motors for case shorts prior to usage. We've now adapted our procedures to assume manufacturing incompetence.) Just in Pittsburgh alone these motors led to multiple trips of our main circuit breaker, trips of the motor breaker and possibly a fried cRIO. (The cRIO is definitely fried, but we're not 100% sure it's the fault of the Banebots. Although I have no idea why we're giving them the benefit of the doubt at this point.)

I highly recommend that any team who experiences weird issues with their robot to check the resistance from the leads to the case of their Banebot motors. Please spread the word to teams who don't read Chief. We saw a lot of teams in Pittsburgh who were having issues, and had no idea it could be traced back to a case short.

[JB987]

Warning seconded...we spent 3 days dealing with case short gremlins...days we could have used programming a two tube auto!

[Jared Russell]

Jared,

I would not be surprised if the RS-775 case shorts were causing your robot to die. We have had an endless stream of issues arising from these motors. Every single motor we have ordered from Banebots has come with or developed a case short. (Some of the motors were not tested until we had already used them. It's not our standard operating practice to test motors for case shorts prior to usage. We've now adapted our procedures to assume manufacturing incompetence.) Just in Pittsburgh alone these motors led to multiple trips of our main circuit breaker, trips of the motor breaker and possibly a fried cRIO. (The cRIO is definitely fried, but we're not 100% sure it's the fault of the Banebots. Although I have no idea why we're giving them the benefit of the doubt at this point.)

I highly recommend that any team who experiences weird issues with their robot to check the resistance from the leads to the case of their Banebot motors. Please spread the word to teams who don't read Chief. We saw a lot of teams in Pittsburgh who were having issues, and had no idea it could be traced back to a case short.

Karthik,

Thanks for the reply. Unfortunately, short of vigilantly changing out the RS-775s every time we detect a case short, I'm not sure what our best course of action is right now. We can drop from 6 drive motors to 4, but the roller claw absolutely requires an RS-775. Maybe non-metallic mounting hardware could at least help reduce the risk of a case short electrifying the entire frame.

[Don Wright]

We are also finding that the case short on our 775's come back after some practice on our practice bot. We will be checking the case on the 775's after every match as part of our after match system check.

We have also found that when this happens, the two banner sensors we have very close to these motors also exhibit the flashing green light occasionally which according to the manufacturer is output overload. This causes us to lose some counts on our lift. If we move our lift by hand, no Banner issues. If the cases aren't shorted, no Banner issues.

So, if you are using the 775's and are experiencing some funny signals from sensors, this could be a suspect. Just FYI...

Unfortunately, we have no way to isolate ours from the frame...unless someone has an idea for non-conductive bolts (other than plastic)...

[Al Skierkiewicz]

Guys,
What you are describing is a perfect example of motor current running through the Crio chassis. Beside the 775 case short, you likely have a sneak path somewhere else on the robot that ties the Crio chassis to frame. When a motor drives in one direction it may be driving the current through the Crio chassis, elevating the +24 volt common rail. This can cause various Crio issues up to and including reboots. Since the sensors are/should be tied to +24 volt rail, they also experience the same power supply issues. Using 24 volt solenoids should also show up some unusual problems in the pneumatics circuits as well.

[Brandon Holley]

Has anyone who has "fixed" their shorted 775s through the zapping process, and experienced the issue returning, tried to fix the 775s again? We have a couple of backups for our competition this week, but if it looks like we're going to be constantly susceptible to failure, it would be good to know if they are "fixable" again.

-Brando

[jwfoss]

2168 had various issues with the 775s on Friday at WPI, we checked both the 775s on our lift for case shorts and they were fine. After a few matches one was clearly hotter than the other and it had burned out the connected jag.

Checked a replacement 775 for the case short and it was fine, installed it, ran for awhile again and then the same problem. Ended up running the lift with only one motor the rest of the competition.

Guess we will be trying the zap fix and hoping for the best before CT.

I am extremely unhappy with the motors right now.

[OZ_341]

I think in light of this continuing issue that FIRST needs to relax the 2011 build rules and allow the replacement of Banebot motors with legal FP motors and/or CIM motors.

It is not ethical or safe to have a faulty motor as one of the alternatives in the KOP. FIRST should relax the rules enough to allow for the removal of all Banebot motors from 2011 machines. Teams designed their robots based on the assumption that these parts met certain safety and performance standards. If this was industry, we would be experiencing a recall right now.
This is what would be right. Why should FIRST or FIRST teams expect anything less?

[Don Wright]

Yes, we zapped, and the issue returned...zapped again...return...repeat...

[Tom Bottiglieri]

I think in light of this continuing issue that FIRST needs to relax the 2011 build rules and allow the replacement of Banebot motors with legal FP motors and/or CIM motors.

There's no problem another CIM motor wouldn't fix!

[MrForbes]

Yes, we zapped, and the issue returned...zapped again...return...repeat...

I'd be interested to see what one of these motors looks like inside, now....

[OZ_341]

I'd be interested to see what one of these motors looks like inside, now....

.....and what is happening to the overall power output every time it gets zapped?
I just wanted to be clear about something here. I am not trying to cause heartache for Banebots or FIRST. In fact I am not even looking to get my money back. But I do think a relaxation of the rules is an important step towards solving this issue for teams that have spent months preparing for a singular moment on the field of play.

When you buy a product it should be safe and it should work within a reasonable range of its intended purpose. These motors do not fulfill even this most fundamental requirement. Yet many of our designs require that we use them. Students in an educational competition should not be in a position where they have to put large amounts of current across the casing of a motor just to get their designs to work.

Question:
Is there any critical mass out there for asking FIRST to relax the rules to keep everyone safe and successful or am I alone on this?
Just wondering, how everyone feels?

[Brandon Holley]

Question:
Is there any critical mass out there for asking FIRST to relax the rules to keep everyone safe and successful or am I alone on this?
Just wondering, how everyone feels?

You have my support. We've dealt with this issue greatly already, and we haven't even competed yet. Unfortunately, for teams that have competed already with the same issues, it would be unfair to unburden other teams who have yet to compete.

-Brando

[Cory]

I'll preface this by saying we haven't had a problem with any of our 775's.

I don't see a rule change as the answer. How is it fair to let teams start using up to 4 more CIM's/ FP's on their robot to replace 775's halfway through the competition season?

Banebots should be testing these motors as they receive them from the manufacturer and not sending out any that are bad.

[OZ_341]

....Banebots should be testing these motors as they receive them from the manufacturer and not sending out any that are bad.
I agree, yet they did send them out to all teams. All we are saying is that they didn't test them and there is no plan to make good on this problem. Yet, we are being forced to use them. We are not looking for a tactical advantage. I just think all teams should be allowed to use the next closest legal items in terms of power curves and weight.

[Swampdude]

We had 1 out of 3 that were originally bad. Then after using 2 for the arm with a p60 256:1 gearbox that failed we had to switch to a CIM on the arm and put the 2 775's in our drive gearboxes with cimulators. As soon as we got in a pushing match they started giving the magic smoke smell and a jaguar burnt out. I suspect the problem wasn't originally detected but is now shorting on both of them. I asked around at the Florida regional and it seemed like everyone was having some sort of banebot troubles, be it gearboxes or case shorts. There are so many FP motors left over from years past, it seems a no brainer to let us use 2 FP's and 5 cim's like in the past. I'm all for that even though we've competed and couldn't launch a minibot one match due to a 775 short.

[Jared Russell]

I could see getting up in arms about allowing teams to replace RS-775s with CIMs, but allowing for a direct swap of RS-775s for Fisher Price motors (2010 or 2011) would actually decrease the total mechanical power available to teams - I'd be all for it.

[Dad1279]

.....
Banebots should be testing these motors as they receive them from the manufacturer and not sending out any that are bad.

I agree, but actually have received an email from Banebots stating:
"The manufacturer does not view this as a defect."

[Tristan Lall]

I agree, but actually have received an email from Banebots stating:
"The manufacturer does not view this as a defect."
In the short run, BaneBots needs to do what they can to resolve the issue, irrespective of the manufacturer's opinion. In the long run, they need to reconsider whether they want to do business with a manufacturer that apparently doesn't know the first thing about quality control.

[Chris is me]

I could see getting up in arms about allowing teams to replace RS-775s with CIMs, but allowing for a direct swap of RS-775s for Fisher Price motors (2010 or 2011) would actually decrease the total mechanical power available to teams - I'd be all for it.

I believe the 2011 FP actually has a higher peak power than the 775-18 at 12 volts.

[Dad1279]

In the short run, BaneBots needs to do what they can to resolve the issue, irrespective of the manufacturer's opinion. In the long run, they need to reconsider whether they want to do business with a manufacturer that apparently doesn't know the first thing about quality control.

In the long run, I hope FIRST will reconsider doing business with a vendor that does not offer teams service, nor warranty refunds/repairs/replacements for DOA products. My last correspondence with Banebots has gone unanswered since Feb 17th.

[OZ_341]

I believe the 2011 FP actually has a higher peak power than the 775-18 at 12 volts.

The important feature to compare is that an FP motor does not cause you to conduct current across your robot frame. In the safety conscious culture of FIRST, I would think that this is a pretty nice feature and a fair engineering trade-off.
Also any differences in the power curve would be offset by the fact that any team could make the change. A small price to pay for safety and reliability.
I think at this point, I am going to stop yacking on Delphi and just take up this issue directly with FIRST. Thanks for everyone's feedback.

[MCahoon]

Note that AndyMark is showing the FP motors are out of stock with expected 8-10 days before shipment could begin.

Even if FIRST would agree immediately to substituting the FP for the 775, it would still be Week 5 before many teams could have a replacement (since not everyone has 2 or 3 FP from previous years).

Important issue to address, but not a solution IMO.

[Tristan Lall]

It just occurred to me that in referring to these as BaneBots' own motors, we're probably perpetuating higher expectations for them. After all, nobody is decrying AndyMark's lead time, because we know they're just a reseller for other companies' motors. By contrast, as far as we know, BaneBots is the one-stop shop for BaneBots motors.

A little more openness about the supply chain (starting with the name of the manufacturer) would probably go a long way toward clarifying which issues are of BaneBots' own making, and which are attributable to the supplier.

Nevertheless, that doesn't exactly excuse not communicating with customers.

[Al Skierkiewicz]

Oz,
The simplest way is to start a thread on the Q&A by asking the question. I know what the answer is going to be but it should get people to start thinking about the issue. Please keep in mind that any manufacturer could have a bad run of product. I am not defending Banebot but just knowing the problems can occur allows the students to learn real world issues with components.

[Ether]

nobody is decrying AndyMark's lead time, because we know they're just a reseller for other companies' motors. By contrast, as far as we know, BaneBots is the one-stop shop for BaneBots motors.

A little more openness about the supply chain (starting with the name of the manufacturer) would probably go a long way toward clarifying which issues are of BaneBots' own making, and which are attributable to the supplier.

I don't think Banebots manufactures motors. They are a reseller. Mabuchi is the manufacturer.

http://en.wikipedia.org/wiki/Mabuchi_Motor

[MrForbes]

I doubt Mabuchi is the manufacturer. They just started the whole "RS-xxx" thing. Lots of companies make motors.

[Jack Jones]

This (http://www.mabuchi-motor.co.jp/cgi-bin/catalog/e_catalog.cgi?CAT_ID=rs_775vcwc) looks like the same motor to me.

[Ether]

I doubt Mabuchi is the manufacturer.


http://www.chiefdelphi.com/forums/showpost.php?p=908067&postcount=13

[Vikesrock]

http://www.chiefdelphi.com/forums/showpost.php?p=908067&postcount=13




That link refers to motors that came in the 2010 Kit of Parts and were not Banebots motors.

[Ether]

That link refers to motors that came in the 2010 Kit of Parts and were not Banebots motors.

Are you saying Banebots has their own motor manufacturing plant for the 2011KoP motors, or are you saying they buy them from a manufacturer other than Mabuchi?

[Vikesrock]

Are you saying Banebots has their own motor manufacturing plant for the 2011KoP motors, or are you saying they buy them from a manufacturer other than Mabuchi?




Neither. Just pointing out that the two motors referenced in the post that you linked are not from this year's kit and were never sourced or available from Banebots.

[Ether]

I doubt Mabuchi is the manufacturer.

What is the basis for your doubt? Mabuchi's reputation?

[OZ_341]

Oz,
The simplest way is to start a thread on the Q&A by asking the question. I know what the answer is going to be but it should get people to start thinking about the issue. Please keep in mind that any manufacturer could have a bad run of product. I am not defending Banebot but just knowing the problems can occur allows the students to learn real world issues with components.

I understand what you are saying, but Banebots should be standing behind their bad product run and FIRST should be forcing them to do so.
In the real world I would just go to another motor manufacturer and never use Banebots again, but I am not allowed to do that. So the real world analogy does not completely apply here.
A nice lesson for the students would be showing them how a company should stand behind their products. If Banebots does not want to be an example company for students, then they should not work with students, period.

[Andy Baker]

Note that AndyMark is showing the FP motors are out of stock with expected 8-10 days before shipment could begin.

That 8-10 day delay was posted about 10 days ago. We have not received the new shipment from F-P yet, but we will within a day. Once these are here, then we will open up orders. I really don't like opening up order for items like this until we see the motors here.

So, my best guess is that they will be available again at AndyMark by Wednesday, March 16.

And... yes, in a general sense, we are looking at this entire issue and seeking ways to improve things for the FIRST community next year. I don't want to go into specifics publicly, but I am very open for suggestions regarding what to do for 2012.

Andy B.

[JVN]

And... yes, in a general sense, we are looking at this entire issue and seeking ways to improve things for the FIRST community next year. I don't want to go into specifics publicly, but I am very open for suggestions regarding what to do for 2012.

Andy B.

Unlimited CIMs. The weight of the motor plus the limited power of the battery provides a good enough tradeoff that teams won't get an "unfair" advantage from using lots of them. That motor is also easy to use, and there are lots of wonderful options available for inexperienced teams.

Veterans will be happy.
Rookies will be happy.
JVN will be happy.

No more garbage motors in the interest of "variety."

-John

[Brandon Holley]

Unlimited CIMs. The weight of the motor plus the limited power of the battery provides a good enough tradeoff that teams won't get an "unfair" advantage from using lots of them. That motor is also easy to use, and there are lots of wonderful options available for inexperienced teams.

Veterans will be happy.
Rookies will be happy.
JVN will be happy.

No more garbage motors in the interest of "variety."

-John

Building on this, FIRST seemed to attempt the "pick a motor that suits you" system this year with the Banebots motors. It's a good idea, but the quality of some of the motors left much to be desired.

The CIMs have proven to be as close to indestructible one could hope for in a motor for FRC. With the way drivetrains have progressed you pretty much have to use them in the DT to stay competitive. Even 1 additional CIM goes a long long way.

-Brando

[billbo911]

Building on this, FIRST seemed to attempt the "pick a motor that suits you" system this year with the Banebots motors. It's a good idea, but the choices of motors left much to be desired.

-Brando

Your point is well stated, but I think the wording might not quite be accurate.
I believe a better choice might be:

Building on this, FIRST seemed to attempt the "pick a motor that suits you" system this year with the Banebots motors. It's a good idea, but the quality of some of the motors left much to be desired.

[MrForbes]

What is the basis for your doubt? Mabuchi's reputation?

If the motors said "Mabuchi" on them, then I would think they might be Mabuchi motors. Aside from that, the term "Mabuchi motor" has become slightly generic, referring to any motor that is a copy of the original Mabuchi style of motor.

I could be wrong...but I doubt it.

[Chris is me]

Unlimited CIMs. The weight of the motor plus the limited power of the battery provides a good enough tradeoff that teams won't get an "unfair" advantage from using lots of them. That motor is also easy to use, and there are lots of wonderful options available for inexperienced teams.

Veterans will be happy.
Rookies will be happy.
JVN will be happy.

No more garbage motors in the interest of "variety."

-John

I love this, with one caveat: I don't love all future roller claws I make weighing at least 6 pounds.

Unlimited CIMs and unlimited Globes, or unlimited CIMs and unlimited Windows would be better.

[MrForbes]

Unlimited CIMS, unlimited window motors. I like that. We have a dozen Denso window motors, never used them until this year.

[Ether]

If the motors said "Mabuchi" on them, then I would think they might be Mabuchi motors. Aside from that, the term "Mabuchi motor" has become slightly generic, referring to any motor that is a copy of the original Mabuchi style of motor.

I could be wrong...but I doubt it.

I was assuming that Mabuchi doesn't necessarily stamp their name on motors they manufacture for re-branders. I could be wrong.

Mabuchi is the world's number one manufacturer of small motors. So if it looks like a duck and walks like a duck... unless you factor in that they probably wouldn't retain their dominant market leadership for very long cranking out junk. That's why I asked if your doubts were based on Mabuchi's reputation.

[artdutra04]

I was assuming that Mabuchi doesn't necessarily stamp their name on motors they manufacture for re-branders. I could be wrong.

Mabuchi is the world's number one manufacturer of small motors. So if it looks like a duck and walks like a duck... unless you factor in that they probably wouldn't retain their dominant market leadership for very long cranking out junk. That's why I asked if your doubts were based on Mabuchi's reputation.While the part numbers and operating specs may match available Mabuchi motors, I wouldn't be surprised if the BaneBots motors were actually made by a Chinese clone manufacturer. Protecting intellectual property there is very difficult to enforce, and as a result their market is saturated with all kinds of inferior clone and knockoff products.

For example, none of the RS775 motors listed here (http://search.china.alibaba.com/selloffer/k-RS775_n-y.html) listed Mabuchi as their manufacturer, but rather a variety of Chinese companies.

[MrForbes]

Art explained my thinking, thanks Art

[MCahoon]

I really like the range of motor options FIRST made available this year. I think a possibility might be that FIRST provides the specifications the motors must meet - but leaves the choice of supplier up to the team. I think it reflects a more "real world" approach. Virtually any company in business for the long run develops a preferred provider list because they know they will get the quality/quantity/delivery time/cost from those vendors. If FIRST had specified any RS-775-18 with free speed XX, stall torque XX, peak power XX, etc. I could have ordered directly from Mabuchi or a number of other vendors. I could provide specification sheet from the vendor to verify the motors comply to the specification.

[EricVanWyk]

Unlimited CIMs. The weight of the motor plus the limited power of the battery provides a good enough tradeoff that teams won't get an "unfair" advantage from using lots of them. That motor is also easy to use, and there are lots of wonderful options available for inexperienced teams.

Veterans will be happy.
Rookies will be happy.
JVN will be happy.

No more garbage motors in the interest of "variety."

-John

I can't wait to see two 8-CIM drive trains in a pushing match.

The only issue I have from an electrical point of view is trying to explain to rookies that unlimited CIMs doesn't mean that an unlimited number of CIMs will necessarily work.

[Brandon Holley]

Your point is well stated, but I think the wording might not quite be accurate.
I believe a better choice might be:

Yes, thank you, I've edited my original post.

-Brando

[JesseK]

I'd support unlimited CIMs if Andy Baker promised not to sell a 4-CIM gearbox except through 'custom' orders that wouldn't be FIRST-legal anyways. :rolleyes: :shudder:

This thread is making me a bit nervous. Our primary lift motor (the one that's bagged) is the FP-673 through an AM Planetary + CIMple box, yet our backup motors (the practice bot + spares) are all RS-775's through BB's gearbox and a CIMple box. Unless we tip, we've found it's not possible to stall/burn out our FP lift motor under normal operations (acme rod = higher torque, less speed, natural braking) so I don't forsee this becoming an issue. Yet perhaps we'll get a spare FP motor tomorrow.

[Don Wright]

Unless we tip, we've found it's not possible to stall our lift under normal operations

I hate to say it, but stalling/not stalling the motor has nothing to do with it.

[JesseK]

I hate to say it, but stalling/not stalling the motor has nothing to do with it.

I meant that for the FP-673 motor that's currently installed on the bagged production bot. Updated it to clarify.

[Ether]

While the part numbers and operating specs may match available Mabuchi motors, I wouldn't be surprised if the BaneBots motors were actually made by a Chinese clone manufacturer.

Mabuchi has 4 factories in China.

Protecting intellectual property there is very difficult to enforce, and as a result their market is saturated with all kinds of inferior clone and knockoff products.

So the argument against the likelihood of the Banebots being Mabuchi comes down to price and "Mabuchi has a reputation to protect".

[EricVanWyk]

Do chassis-faulted motors have different output power? Has anyone stuck them on a dyno?

[Bob Steele]

That 8-10 day delay was posted about 10 days ago. We have not received the new shipment from F-P yet, but we will within a day. Once these are here, then we will open up orders. I really don't like opening up order for items like this until we see the motors here.

So, my best guess is that they will be available again at AndyMark by Wednesday, March 16.

And... yes, in a general sense, we are looking at this entire issue and seeking ways to improve things for the FIRST community next year. I don't want to go into specifics publicly, but I am very open for suggestions regarding what to do for 2012.

Andy B.

My vote would be for a limit of 12 motors.
Teams could choose between CIM,FP, Window with a maximum of 4 each.

with a variety of options already available commercially and team designed...FP motors can be used in most situations and gearboxes designed for CIMS... ( The same way that the banebots motors could...)

But honestly I see no advantage to Window motors... but for variety... fine..

I honestly don't think that all CIMS is a good idea... they are too heavy for many extended applications like a roller claw or something where the motor has to be moved... so the FP is a good substitute.. being lighter.

I like the banebot gearboxes so I think we shouldn't really toss Banebot out for one of their motors...

Our team is using the 550 motor... it seems to work quite well... and it could be substituted into most applications that teams were using the 575's for... we have never seen the case short problem in those motors.

I have used these motors in a number of other applications in classes and they are pretty decent as long as they are supported and the load is supported...they also have the advantage of being really cheap... the form factor is exactly the same as the FP...

We thought about using the RS-775 and ended up using something we had some experience with... the 550... it ended up to work quite well for our application. (An elevator)

I concur with everyone's complaint that Banebot should be standing behind their product. If you remember though, back a few years ago... they did do that... providing new plates for the transmissions that were provided to us...at quite a cost to them as I recall... so I wouldn't write them off... completely... I would imagine that this year was nightmare to them because of their shipping delays and this 775 issue.

They do provide a nice competitive gearbox in a number of ratios for use on our robots with either their motors or the FP.

I like having options... and I really missed having the option of 2 FP motors this year.

Just remember that if you are using the 775 and want to substitute the FP ... that you can substitute the 550 that this is perfectly legal and not too far off the power curve...
You can do that right NOW... without any special action by the GDC

We have never seen this case short problem with a 550...Has anyone else out there?

Good luck on the field...

[Al Skierkiewicz]

While you guys are wishing, remember that the current battery has only so much to give before it can't supply the needed current to keep the Crio happy.

[Tristan Lall]

Sorry that I wasn't as clear as possible above; I know BaneBots doesn't make the motors. I was referring to the fact that we call them "BaneBots motors", when we should be calling them "[unknown manufacturer] motors" sold by BaneBots. (In the same vein as "CIM motors" sold by AndyMark, even though they have an AndyMark part number.)

And I'm quite sure they're not (at least not usually) Mabuchis. (I'd described the reasons in another thread, but sufficient to say, they are missing all the distinguishing marks of a Mabuchi product.)

[Matt Krass]

While you guys are wishing, remember that the current battery has only so much to give before it can't supply the needed current to keep the Crio happy.

Don't you just love reigning in the mechanical guys with electrical details? ;)

Seriously though, I think this fact would be sufficiently limiting on CIM usage, as per John's original post suggesting the motors weight and power consumption would help regulate it. I'm all for unlimited CIMs!

Matt

[Andy Baker]

That 8-10 day delay was posted about 10 days ago. We have not received the new shipment from F-P yet, but we will within a day.

Well, look at that. The shipment just showed up!

2011 F-P Motors (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0821) and associated gearboxes (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0822) and motor-cap products (http://www.andymark.com/ProductDetails.asp?ProductCode=am-0823) are now available.

Thanks for your patience,
Andy

[Ether]

I'm quite sure they're not (at least not usually) Mabuchis. (I'd described the reasons in another thread, but sufficient to say, they are missing all the distinguishing marks of a Mabuchi product.)

Would you please post a link to your list of reasons. Thank you.

[Joe Ross]

Would you please post a link to your list of reasons. Thank you.

http://www.chiefdelphi.com/forums/showthread.php?p=1020327&highlight=mabuchi#post1020327

[Al Skierkiewicz]

Don't you just love reigning in the mechanical guys with electrical details? ;)
Matt

Someone has to do it and I'm just that guy!

[Ether]

Don't you just love reigning in the mechanical guys with electrical details? ;)

Seriously though, I think this fact would be sufficiently limiting on CIM usage, as per John's original post suggesting the motors weight and power consumption would help regulate it. I'm all for unlimited CIMs!


Also, in his post John did not seem to be implying that motor choice be limited to CIMs, only that # of CIMs be unlimited.

[Ether]

http://www.chiefdelphi.com/forums/showthread.php?p=1020327&highlight=mabuchi#post1020327

Thanks Joe. I don't know how I missed that thread.

[Dale(294engr]]

follow up RS-775 Banebots motor rotor short to case problem..

inspection results of new packaged Spare Parts this weekend at LA Regional:

The rotor laminated iron core appear to have NO or insufficient insulation
thus enamel windings eventually short against the core at end (edge turn)

GOOD armatures have a brown fiber or cloth insulation (such as CIM's)
to prevent such winding shorts (enameled wire is not good enough alone)

possibly mfr short cut is relying on a substitute insulator such as epoxy varnish etc which fails to provide adequate thickness around lamination edges

End result: if ALL RS-775's were mfrd in this manner
** NONE ** are safe to use on the robot
as they are likely to continue to degrade with use.

first winding to short does not impact motor physical performance
but will not pass chassis isolation requirement
short(s) can occur mid match.

2nd and subsequent shorts to core represent shorted turns.. each decreasing available torque while increasing current draw=declining efficiency

If you plan to keep the RS775's frequently remove two motor spade to controller (Jag or Victor) and do continuity to case test for each RS775.

Note: the isolation continuity test to chassis will read ~2megohms one direction (polarity) and ~300K ohms the opposite (leads swapped) due to the diode path in the controllers even though the motor lead to case short is only an ohm or two!! Note that in this mode if the motor is slightly rotated the polarity detected for min / max swaps!! i.e. alternates.. due to different H-brdige path in the controller..

Someone should disassemble all the smaller Banebots motor types to verify/report here if their rotor lamination's lack proper insulation.. TBD...

I'm unaware of any such failures to date. Perhaps smaller wire diameter does not pose as great a potential enamel break thru as the much larger AWG wire used on the 775 armature's.

[Ether]

;1045989']The rotor laminated iron core appear to have NO or insufficient insulation thus enamel windings eventually short against the core at end (edge turn) ... possibly mfr short cut is relying on a substitute insulator such as epoxy varnish etc which fails to provide adequate thickness around lamination edges

Sounds like a larger radius on the core edges would go a long way toward mitigating this problem?

[theprgramerdude]

So, now it's 2012, and these motors are legal again. Any word on whether the problem has been fixed?

Plus, my memory of all this is a little hazy, does/did this issue extend only to the 18V model, or did it include the 12V model as well?

[JJackson]

Anyone that saw the Einstein finals last year may know why we aren't using bane bots this year.

[sanddrag]

Anyone that saw the Einstein finals last year may know why we aren't using bane bots this year.Would you mind explaining?

[Alden94]

Would you mind explaining?

Let's just say 177 and 2016 did very well without us. They say your critical components fail at the worst times and it is most certainly true. Watch the matches.

[Alden94]

Let's just say 177 and 2016 did very well without us. They say your critical components fail at the worst times and it is most certainly true. Watch the matches.

See http://www.chiefdelphi.com/forums/showthread.php?t=95031&highlight=781+Einstein Paragraph 7 for an explanation of our unfortunate luck on Einstein 2011.

[JJackson]

Basically our arm was run by the bb775 which shorted out when it hit a certain spot ... Disconnecting communication. At the time we couldn't figure out what was happening we even tried rotating the arm between matches and it worked but we musn't have tested it's full range of motion. So when our auto mode raised the arm we lost comms. After champs we found out that many other teams had the case short problems so we decided we probably won't use banebots for a few years. We also have had problems with banebots before that (2007 I believe) and last year we thought they had been improved so we would try them again.

Having said that the only problem we had with the banebots motors last year was in those last few matches at champs and we went to three competitions before champ.

[Al Skierkiewicz]

J,
What you describe is exactly what will happen with the Crio shorted to frame. It will only occur when the motor is run in one direction. What occurs is that the motor drive signal is opposite polarity to the power input to the Crio. When the motor is turned on in that direction the motor voltage bucks the Crio power supply through the #18 AWG wiring causing the Crio to reboot. The resulting voltage is less than the Crio minimum power input of 19 volts. If the Crio didn't reboot (disabling all outputs) the resultant current path would eventually burn open the #18 wiring. If you had mounted the Crio on an insulated mount, it may have shifted so that the chassis contacted robot frame or something was pushed against the Crio mounting hardware from underneath. When another official I looked into your robot during finals, I did not see anything obvious. I did not turn it over and look at it from underneath. It is also possible that when your arm moved, a wire was pinched in the mechanism and it was not the fault of the motor at all.

[JJackson]

the main reasonwe thought it was the motor was because after we switched it out everything worked. We actually cover the entire bottom of the crio with Velcro and that's how it is attached. It also wasn't the directin but every time it happened the arm was in the same spot

[MrForbes]

The motor spins many revolutions as it moves the arm, right? Which means the motor is in it's same spot many times as the arm moves. So it was most likely a wire being pinched by the arm at that spot, or something that moved on the robot as the arm moved

Also the short I found on dissecting a motor, was continuous, it would not change as the motor turned.

[Jared Russell]

781: How many RS-775 motors were on your robot in total in 2011? What we ultimately found to be the cause of our robot dying on the middle of the field at the Florida Regional was that we had a pair of RS-775s that became case-shorted at a certain spot in their rotation over the course of competition. It was frustratingly hard to reproduce in the pit. Our theory was that when both motors were case shorted at the same time (e.g. bad luck), current was able to flow between them. This added draw lowered the battery's voltage and caused reboots.

Since this thread has been bumped in 2012, it is a good time to ask: Has anyone run into case short issues with the 775 motor purchased this year?

Regardless, thanks to the best motor rules in years, we will be avoiding using RS-775 motors for the foreseeable future.

[Al Skierkiewicz]

Everyone,
I was informed that the manufacturer of last year's motor is no longer supplying those motors to Banebots. Whether there are any still in the supply chain is something for each team to determine. Please check any you plan on using, with an ohmmeter and rotate the shaft during your checks.

[camtunkpa]

We got our 4 Banebots 775's in last night and 3 out of the 4 have issues.

One motor had about 2M ohms of resistance between the terminals and the case. After running the motor for a about 5 minutes the motor must have cleared whatever debris was causing the reading.

The second motor read 13 ohms between the terminals and the case. We started by "zapping" the debris as was recommended last season to clear case shorts. After zapping the motors we had a 1M ohm resistance between the terminals and the case. We are still working with this motor to clear the debris causing the resistance.

The third motor was the best of them all. It had no case short and the resistance between terminals was good, but only one minor problem...the shaft doesn't spin at all. The motor is completely locked up.

I have a call into Banebots and will post their response to our issues.

I just hope other teams are having better luck with these motors then we are. The 775s are a nice motor when they are working properly.

[Brandon Holley]

We got our 4 Banebots 775's in last night and 3 out of the 4 have issues.

One motor had about 2M ohms of resistance between the terminals and the case. After running the motor for a about 5 minutes the motor must have cleared whatever debris was causing the reading.

The second motor read 13 ohms between the terminals and the case. We started by "zapping" the debris as was recommended last season to clear case shorts. After zapping the motors we had a 1M ohm resistance between the terminals and the case. We are still working with this motor to clear the debris causing the resistance.

The third motor was the best of them all. It had no case short and the resistance between terminals was good, but only one minor problem...the shaft doesn't spin at all. The motor is completely locked up.

I have a call into Banebots and will post their response to our issues.

I just hope other teams are having better luck with these motors then we are. The 775s are a nice motor when they are working properly.



Cliff I think you just confirmed for us our total avoidance of the 775 this year. I don't know if I could make it through another failure in a finals match again :cool:

-Brando

[MrForbes]

We're kind of ignoring the existence of bb motors this year....

[billbo911]

We're kind of ignoring the existence of bb motors this year....

Seriously??
Completely ignoring BB motors is like not informing your students of the scholarships available to them through FIRST.

Sure, ignore the 775, that I agree with 100%, but the 395, 540 and especially the 550 are great motors in the right application.

[MrForbes]

Yeah, seriously.

I don't get the analogy.

[Andrew Lawrence]

We're kind of ignoring the existence of bb motors this year....

The existence of what? I have never heard of a Banebots 775. I could have sworn they only went up to 550. Oh well, it must have been a mistake from banebots, there's no way they could make a 775.

Yeah, we're staying clear of 775's this year. One that we ordered was so bad, we got every team member around it, told them how terrible it is, and then proceeded to hit it with a hammer. Then it broke, and we danced on the parts.

We're definitely using 550's this year, but we prefer to think that 775's, like 2009, didn't exist. :)

[camtunkpa]

Cliff I think you just confirmed for us our total avoidance of the 775 this year. I don't know if I could make it through another failure in a finals match again :cool:

-Brando

I'm still waiting to see what they do to make things right before we ban the 775 from our machine. If we do use them on our bot I will be keeping a close eye on them.

We managed to have good luck with the 775 last year. We had a single one on our lift last season that still works just fine after 4 competitions and lots of demonstration time.

[MrForbes]

WE have 550 sized motors from FP and AM.

[JamesCH95]

The set of 775 motors we've gotten this year have performed flawlessly so far, just like every other 775 motor we've gotten. By luck of design we haven't had an electrical connection between the case and any main part of the robot, or the other motor, and everything has been fine.

[jason701802]

We're kind of ignoring the existence of bb motors this year....

Are you seriously ignoring the second best motor in the KOP (following the CIM) just because it has a little, easily avoidable, problem. As far as I can tell, the case shorting does not hinder the motion of the motor directly, it can only cause problems when connected to an improperly isolated frame. I understand that creating a perfectly isolated frame is sometimes difficult and the easiest way to avoid the problem is to isolate the motor, eg, by putting the motor in a plastic housing like a drill motor transmission or even a PF gearbox. I still don't know whether either of the 775s we used last year had case shorts because the way we used them, it didn't matter.

[MrForbes]

I took apart a 775 last year, and found the cause of the "case" short. Nothing is shorted to the case, the winding is shorted to the armature. Since they haven't fixed the problem this year, I have no confidence in the motor.

We used the 540/550 BB motors and gearboxes in previous years, when the gearboxes were provided in the kit. They worked fine for us.

We can find other ways to make things move.

[jason701802]

I took apart a 775 last year, and found the cause of the "case" short. Nothing is shorted to the case, the winding is shorted to the armature. Since they haven't fixed the problem this year, I have no confidence in the motor.

One winding is shorted to the armature? So what? As I understand it, that shouldn't affect motor performance. The 775 is much more resilient than a 550 and, in most cases, requires less reduction.

[billbo911]

...... I don't get the analogy.

Essentially you are turning your back on some very reliable and powerful motors if you exclude all BB motors.
By not informing your students of the scholarships available to them by participating in FIRST, you would be turning your back on extraordinary opportunity for them.

Yeah, kind of convoluted, but I think you can see where I was headed with that.

Bottom line:
RS775 = NO
RS550 = YES
RS540 = YES
RS395 = YES
...........

[Ether]

I took apart a 775 last year, and found the cause of the "case" short. Nothing is shorted to the case, the winding is shorted to the armature.

http://www.chiefdelphi.com/forums/showpost.php?p=1028049&postcount=74

http://www.chiefdelphi.com/forums/showpost.php?p=1028184&postcount=82

[AdamHeard]

One winding is shorted to the armature? So what? As I understand it, that shouldn't affect motor performance. The 775 is much more resilient than a 550 and, in most cases, requires less reduction.

The 775 does require less reduction, but with it's known flaw it isn't the clear choice for most teams. No need to mock someone for ruling them out.

As long as the rules let you choose between the 550 and 775, we will NEVER use those specific 775 motors (not all 775s, as I have several for other projects that are champs).

The 550 is trivially weaker, a good deal lighter (which is a con in some systems for heat dissipation), and is nearly the exact same as the generic average FP we get year to year that has proved to be a reliable champion in FRC.

TL;DR. I agree with squirrel and others; 550's are the way to go.

[jason701802]

I'm not mocking, I'm questioning the reasoning to avoid such a great motor when its only little flaw can be avoided so easily. I understand being extra careful with the motor and not wanting to use it in a BB or similar transmission, but completely ignoring the 775 seems quite rash.

[Brandon Holley]

I'm still waiting to see what they do to make things right before we ban the 775 from our machine. If we do use them on our bot I will be keeping a close eye on them.

We managed to have good luck with the 775 last year. We had a single one on our lift last season that still works just fine after 4 competitions and lots of demonstration time.

It seems if you get one without defect, it appears to be a great motor. The problem for us was getting our hands on one without defect.

Avoiding if possible just for our own sanity.

[camtunkpa]

FWIW I just got off the phone with Banebots and they are going to replace our motors. I talked to tech support and the gentleman seemed baffled because they are testing/checking all the motors before they are sent out.

We will still give the 775 a shot after our success using it last year, but I will always have some doubt about the motor. I will make sure we always have a plan B

[Tristan Lall]

Everyone,
I was informed that the manufacturer of last year's motor is no longer supplying those motors to Banebots. Whether there are any still in the supply chain is something for each team to determine.Doesn't that mean that there are (at least) two different models of motors using the same BaneBots part number?

To which motor(s) do the present specs on the BaneBots page apply?

Does FIRST know that there are multiple motors, and is FIRST alright with this? up to 4, in any combination, of the BaneBots motors provided in the KOP (acceptable part numbers are M7-RS775-12, M7-RS775-18, M5-RS550-12, M5-RS550-12-B, and M3-RS395-12)This might be legal if either: Both types of 775s were provided to various teams in the KOP; or The "acceptable part numbers" part takes precedence over "the BaneBots motors provided in the KOP".

[artdutra04]

If this year's batch of Banebot RS775 motors also suffers from a lot of case shorting problems, but still delivers on the 273 Watts claimed in the motor spec sheets, then there is an easy solution: complete electrical isolation from every other metal part on the robot.

This must be done both via the mounting plate (I'm thinking either Lexan or Delrin) and via the motor gearing (I'm thinking steel or brass pinion on motor, then using an Delrin/acetal spur gear for the first reduction). To achieve the latter requirement, I'm thinking this can easily be achieved by going 24DP for the first gear reduction and making a custom hex/keyed aluminum hub for the VEX 60-tooth High Strength gear (http://www.vexrobotics.com/products/accessories/motion/276-2250.html) (yup, I'm biased ;)), as shown below:

http://img692.imageshack.us/img692/8784/vex60thsgearwith0375hex.png

[Chris is me]

The set of 775 motors we've gotten this year have performed flawlessly so far, just like every other 775 motor we've gotten. By luck of design we haven't had an electrical connection between the case and any main part of the robot, or the other motor, and everything has been fine.

So you have non-metal pinions and screws on your motor? To me it seems VERY hard to electrically isolate a 775.

[Brandon Holley]

So you have non-metal pinions and screws on your motor? To me it seems VERY hard to electrically isolate a 775.

You essentially have to use something like Art's suggestion above to get total electrical isolation.

When we ran into case short issues last year, the first tactic was to isolate the motor. We tried many things hoping that if we could eliminate all but the pinion electrical connection we would at least cut down on the issue. It didn't matter, after isolating everything but the pinion, the short was still present through the whole frame.

-Brando

[MrForbes]

The armature is pressed to the shaft, the windings are shorted to the armature. That's what I'd expect to happen.

[Al Skierkiewicz]

Not that I am trying to sell Banebots, but I have it on good authority that the source of the shorted motors is no longer supplying parts to Banebots. I am not pushing you to use them but if you do, please test while rotating and report your findings. Thanks in advance.

[JamesCH95]

So you have non-metal pinions and screws on your motor? To me it seems VERY hard to electrically isolate a 775.

Not at all hard, just requires a judicious application of non-conducting materials. In our 2011 robot it happened by accident. In our 2012 robot it happened by design.

In this picture are the two from our 2011 robot. They are both mounted to wood and are chained to an axle supported by plastic (rulon) plain bearings. They have worked flawlessly through driver training, a Week 0, GSR to 3rd semi-final match, Palmetto to 1/4 finals, and many more hours of demos.

http://i.imgur.com/iPZAZ.jpg

Here is a picture of our prototype shooter, the motors and everything metallic they are connected to are mounted in lexan plates, no problem.

http://i.imgur.com/b018x.jpg

[WileyB-J]

rather nice prototype you got there!

[Tristan Lall]

Not that I am trying to sell Banebots, but I have it on good authority that the source of the shorted motors is no longer supplying parts to Banebots.If so, that's a step in the right direction for BaneBots' customer service.

But do you think you could prod FIRST to take official notice of this fact, and clarify their position on the legality of the different motor types, and their specifications? (As is, depending on the particulars, it could be a repeat of BaneBots' mystery motors from 2009—we never did find out what the plastic-endcapped motors were, or what FIRST thought of them.)

[Jeff Waegelin]

Got an order of RS-775 motors in today, and this is what I saw when I opened the box. Doesn't exactly make me encouraged about their quality control, when the motors aren't even securely packed and are rattling around inside the box. I'll report back once I've had a chance to test them tonight.

[Jeff Waegelin]

Update: Art and I tested the whole shipment - we had 3 out of 16 motors with case shorts. It's an improvement from last year's results, but still much worse than I'd consider acceptable.

[MrForbes]

I guess that's why we are pretending they don't exist. Thanks for the data.

[Brandon Holley]

Update: Art and I tested the whole shipment - we had 3 out of 16 motors with case shorts. It's an improvement from last year's results, but still much worse than I'd consider acceptable.

Ughh.

Thanks for the update Jeff.

[Chris is me]

I guess that's why we are pretending they don't exist. Thanks for the data.

Amen to that. No Banebots at all costs here.

[AdamHeard]

Amen to that. No Banebots at all costs here.

The 550 motors, p60 line of gearboxes and Cimulator are all great products; unsure as to why you'd avoid them at all cost.

[Chris is me]

The 550 motors, p60 line of gearboxes and Cimulator are all great products; unsure as to why you'd avoid them at all cost.

It's more of an ethical issue than a practical one - if they have crappy 775s and continue to ship them out, I don't trust their quality control overall when I have reputable companies with better service to supply me with motors.

[Ether]

Got an order of RS-775 motors in today, and this is what I saw when I opened the box.
Update: Art and I tested the whole shipment - we had 3 out of 16 motors with case shorts. It's an improvement from last year's results, but still much worse than I'd consider acceptable.

Might I ask: do all the motors appear to be identical? Or does it look they are not all made by the same manufacturer...

[artdutra04]

[I]Might I ask: do all the motors appear to be identical? Or does it look they are not all made by the same manufacturer...All of the Banebot RS775 motors we have (both existing ones from 2011 and the recently arrived ones from 2012, including both case-shorted and non case-shorted motors from both years), look completely identical. They both even have exactly the same writing printed on them:
RS775WC-8514
DC18V/CCWin the exact same location on the flux ring.

The only difference is the 2011 motors were shipped with an orange Banebots sticker on them.

Edit: If Banebots did supposedly switch to a new supplier, I'm wondering if these are the remainder of old motors from last year they had in stock?

[Ian Curtis]

Got an order of RS-775 motors in today, and this is what I saw when I opened the box. Doesn't exactly make me encouraged about their quality control, when the motors aren't even securely packed and are rattling around inside the box. I'll report back once I've had a chance to test them tonight.

If all the Styrofoam is in the box, how do you know BB is at fault? Shipping companies don't intentionally damage goods, but they move a truly monumental number of packages and occasionally stuff gets dropped/run-over/what have you.

[AdamHeard]

It's more of an ethical issue than a practical one - if they have crappy 775s and continue to ship them out, I don't trust their quality control overall when I have reputable companies with better service to supply me with motors.

That's four very high power motors your skipping out on for your robot (the 550s).

[Karthik]

That's four very high power motors your skipping out on for your robot (the 550s).

"Fool me once shame on you, fool me twice shame on me."

A lot of teams are naturally gun shy about these motors because of the huge failure rates teams saw last year. I'm not surprised at all that some teams are taking a "better safe than sorry" attitude when it comes to the 775's. Much like most things in life, it comes down to the risk to reward ratio. Is the higher power available from the 775's enough to justify the risk of my robot having severe electrical issues? Each team's decision will be based on just how risk adverse they are and how high of a risk they view the situation as. I know on 1114 we'll be giving these motors another chance, but at the first sign of trouble they'll be introduced to our arbor press.

[Mr. Lim]

...I know on 1114 we'll be giving these motors another chance...


At least 4 losses could be directly attributable to case shorted 775s during our 2011 season. We tested them all prior to competition season. A short developed throughout Waterloo and ultimately started causing problems in GTR.

Even though checking the resistance between every match got us through Champs, we had to "blast" them 3-4 times, each time holding our breath hoping that it would work.

We got lucky... it worked every time.

A year off for the 775s is the plan so far for us. If we're forced to us them, they'll be completely electrically isolated. Plastic mounts, and 1st stage gearing.

[Ether]

Edit: If Banebots did supposedly switch to a new supplier, I'm wondering if these are the remainder of old motors from last year they had in stock?

Well that was really what I was getting at. How many freight cars of these things do they have in inventory. Maybe they're selling the new ones to non-FRC customers. Sorry to be so cynical.

[PAR_WIG1350]

I know on 1114 we'll be giving these motors another chance, but at the first sign of trouble they'll be introduced to our arbor press.

Your going to crush them? If you do, can you post pictures/a video? On a side note, it would be cool to see a motor cut along its axis bisecting the shaft and case ;).

[Dale(294engr]]

Hmmmm.... Just our luck I went and checked our 3, 2 of which were conductive. What exactly makes them "bad"? I have not heard why exactly this a problem.
This is a mfr defect carryover from last year. Appears Banebots may be dumping known defective 775's on FIRST as I and others contacted Banebots
but they resisted acknowledging there was a problem.
I personally performed failure analysis, witnessed shorted turns to rotor core.

RS-775 rotors use epoxy coated core laminations as insulation, ineffectively.

(most motors use brown fiber insulation. check out CIM rotor. Epoxy, properly quality controlled, MAY allow a more compact motor & less labor to mfr)

Enamel windings short at iron lamination corners via break thru at tight bend.

Two windings shorted behaves as a shorted transformer winding
causing no load motor current to quickly increase, depriving motor of torque

if short to motor case = robot AL frame, it is Illegal and failed at inspection

(theoretical remedy: electrically isolate each motor to pass inspection, but problem will likely escalate as more turns shorted draws higher current & produces less torque; high localized heating leads to catastrophic smoke)

Shorts I measured were typically ~0.1 ohm to case (either terminal to case)
which requires a careful low ohm set-up

It's a smoking gun again this year.. This is a great well made motor otherwise.
PreTesting out of new box is essential if decision to use these.
At a regional last year 70% of new boxed spare parts 775's were shorted!

causing huge delays for teams counting on them (Team 207 et al)

[Al Skierkiewicz]

Adding to Dale's post...
The epoxy coating in and of itself cannot protect this problem from occurring. The vibration of the motor turning, heat cycling during operation and movement within the windings will eventually break through the enamel coating used to insulate the motor wires. The breakdown at the very least will cause the case short and as stated as more windings breakdown, current flows through the armature and from the armature to the case. As heat builds up for these conditions, further deterioration will occur robbing motor power and drawing higher currents. Sorry guys, I thought Banebots had solved the issue and it was behind us.

[MrForbes]

If all the Styrofoam is in the box, how do you know BB is at fault? Shipping companies don't intentionally damage goods, but they move a truly monumental number of packages and occasionally stuff gets dropped/run-over/what have you.

Exactly....the sender is responsible for packing the items sufficiently well to prevent damage under typical shipper handling.

I encounter this problem a lot when buying stuff on ebay, not many people know how to pack stuff. The most important thing is to not leave any empty space in the box, if the items are relatively heavy. Motors are heavy, the box needed to be filled with packing material, not air.

[SM987]

Just tested ours; one out of five was shorted. Disappeared after a zap, but it will be our worst case scenario backup.

[JesseK]

Ever since the 550's got their plastic fins to push air, they hold up much better than they used to. I'd seriously reconsider ignoring them altogether.

Early adopters: either they're the bird that gets the worm, or they're the worm that gets eaten by the bird!

[Chris is me]

Ever since the 550's got their plastic fins to push air, they hold up much better than they used to. I'd seriously reconsider ignoring them altogether.

I'm just saying how can you trust the Banebots brand when they are practically synonymous with poor quality control? AndyMark has much better service than them, so I'm going to use all AndyMark motors on my robot. Seems simple to me.

[jason701802]

;1109619'](most motors use brown fiber insulation. check out CIM rotor. Epoxy, properly quality controlled, MAY allow a more compact motor & less labor to mfr)

That may be true of large industrial motors, but just look at all the other 300, 500, and 700 series motors in the kit and in other places, they almost exclusively use enamel coated wire. This is especially true of RC car motors, most of which are higher current than any that come in the kit and are 500 series motors.

Even the van door motor and the CIM that I've taken apart have used enamel wire, admittedly it was an old CIM. I don't think any motors in the KOP use fiber wire insulation, and I'd very much like to see one that does.

[Al Skierkiewicz]

Jason,
The OP is referring to insulation between the enameled wire and the armature. It has different names but the effect is to protect the corners. Using enameled wire is virtually the only way to efficiently develop a magnetic field with the minimum amount of wire.

[jason701802]

Al,
That makes a lot more sense, but I still don't think it's as common as he claims, most motors I've torn apart just use a nice think layer of enamel.

[waialua359]

We got several that came in the other day and we have the same problem with ours as well.
This is/may be the first time we use Banebots this season.
We never touched them before ever since they had the transmission issues in their inaugural year being in the FIRST kit of parts.

[Karthik]

I know on 1114 we'll be giving these motors another chance, but at the first sign of trouble they'll be introduced to our arbor press.

Four brand new motors arrived today. All shorted. I'd call this the first sign of trouble...

http://desmond.yfrog.com/Himg736/scaled.php?tn=0&server=736&filename=voqqh.jpg&xsize=640&ysize=640

We will not be using any RS-775 motors this year.

[Andrew Lawrence]

Four brand new motors arrived today. All shorted. I'd call this the first sign of trouble...

http://desmond.yfrog.com/Himg736/scaled.php?tn=0&server=736&filename=voqqh.jpg&xsize=640&ysize=640

We will not be using any RS-775 motors this year.

This just made my day! :D

[Bochek]

This is all very scary to read. We just ordered 4 of these motors. And where planing on using 2 on the robot.

Gonna have to test them out heavily before competition.

Has anyone experimented with trying to fix the shorts?

- Bochek

[Tom Bottiglieri]

;1109619']
(theoretical remedy: electrically isolate each motor to pass inspection, but problem will likely escalate as more turns shorted draws higher current & produces less torque; high localized heating leads to catastrophic smoke)

This is a pretty important point. Just isolating the motors won't fix all of the issues. These motors do get worse over time and will fail, regardless if they are shorted to your frame.

[team222badbrad]

I shipped two of the four defective ones received back to BaneBots. We are awaiting the replacements. Once we get them we will let you know the prognosis.

Let's hope the these motors can at minimum spin...

I'd say it's pretty bad when you get a motor that can't even spin. I wouldn't doubt it was caused by poor packaging as our four 775's were shipped in a USPS small flat rate box.

Also we have noticed over the years that BaneBots enjoys "throwing" components in small flate rate Priority mail boxes. If I recall they shipped our planetary gearboxes last year like this with no padding and the box was bulging because they barely fit.

Poor quality control, long lead times (at least for us last year), and poor packaging. I don't blame anyone who has or is considering not using BaneBots as a robot part supplier. The same applies in the real world.

[Tristan Lall]

I'd say it's pretty bad when you get a motor that can't even spin. I wouldn't doubt it was caused by poor packaging as our four 775's were shipped in a USPS small flat rate box.
Brilliant work, BaneBots. You've obviously figured out how to make a shipping box larger on the inside than on the outside.

An RS-775 motor (http://banebots.com/pc/MOTOR-BRUSH/M5-RS775-12) is Ø1.85 in. A USPS small flat rate box (https://shop.usps.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10052&productId=10001641&langId=-1) is for items up to 1.625 in thick. That leaves -0.113 in for padding on each side of the motor.

Let's see if BaneBots owns up to the packaging error, and provides free (working!) replacements in a timely fashion.

[Jeff Rodriguez]

WE got two 775s in and both of them are good. No signs of any defects.

[R.C.]

Four brand new motors arrived today. All shorted. I'd call this the first sign of trouble...

http://desmond.yfrog.com/Himg736/scaled.php?tn=0&server=736&filename=voqqh.jpg&xsize=640&ysize=640

We will not be using any RS-775 motors this year.

We ordered 2 775's and 15 550's. 550's were all good, both 775's were bad. We are definitely not using 775's this year.

My kids followed your lead and did the same...

We used 775's all last year and had zero issues till the offseason and offseason presentations. Its pretty embarrassing when your robot won't work in front of a sponsor who donates over ($5,000) a year due to case shorts... We fixed the issue by swapping to a new 775.

Chris and others, 550's are some awesome motors and the cimulator/p60's are awesome as well. Don't rule out a supplier because of one issue, I know its a big issue but 550 are very good motors.

-RC

[Jared Russell]

A manufacturing issue resulting a large number of defective motors is understandable; it happens to every supplier at one point or another. But continuing to sell the defective products to teams a full year later is just unbelievable.

I am very happy that the 2012 parts utilization rules make building a high-performing robot without BaneBots products an option.

[MrForbes]

But continuing to sell the defective products to teams a full year later is just unbelievable.

That's where I'm coming from

[Ether]

at the first sign of trouble they'll be introduced to our arbor press.

Instead of crushing them, could I talk you into frying them instead? Hook them up to 12 volts and let us know how long it takes to release the factory smoke. That might be a useful bit of data for folks who are considering using them on drivetrain.

[Mrpalmere]

The RS-775 motors have a know issue with a short to thr frame. The easy fix is to run 12v from terminal to frame. Do this independently from the other terminal. If there is indeed a short to the frame, it won't be after you do this process. We had this issue last year and shorted each terminal, independently, to the frame of the motor and ran those motors all season with no problem.

[Ether]

We had this issue last year and shorted each terminal, independently, to the frame of the motor and ran those motors all season with no problem.

I'm sure you meant "applied 12 volts between" instead of "shorted".

[Karthik]

Instead of crushing them, could I talk you into frying them instead? Hook them up to 12 volts and let us know how long it takes to release the factory smoke. That might be a useful bit of data for folks who are considering using them on drivetrain.


We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

[Ether]

We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

Thank you.

[theprgramerdude]

We locked the motor and hooked it up to a 12V battery. The magic smoke was released approximately 0.5 seconds after stall, perhaps less.

Do you happen to have a spare RS-550 laying around to test the same thing with?

[Ether]

Do you happen to have a spare RS-550 laying around to test the same thing with?

The 775-18 is 273 watts at stall at 12 volts.

The 550 is 254 watts at stall and is much less massive than the 775-18.

Read this thread:
http://www.chiefdelphi.com/forums/showpost.php?p=877987&postcount=34

[OZ_341]

I know as engineers we just love to solve problems. But the fact of the matter is that we should not be fixing these motors. FIRST and Banebots are knowingly sending out case shorted motors for use by children. (Yes, "children")

With all of our supposed focus on safety, FIRST should be demanding the immediate recall of all 775 motors for the season. No exceptions.

They are simply a hazard. Regardless of whether an adult works on the robot or not, you have the potential for a child to contact a machine which is drawing amps across the open robot frame.

When the problem has been understood for over a year, there is no excuse for distributing something so dangerous.

[the man]

I wouldn't call them dangerous to people per-say but definitely dangerous to electronics, and completely unacceptable. First should find a good solutions, and alternative or a stern talk with banebots.

[Karthik]

Do you happen to have a spare RS-550 laying around to test the same thing with?

No, the only reason we're willing to do destructive tests with the RS-775's is because they're defective and unsuitable for competition. They're scrap metal to us.

[IKE]

Maybe the 775s should be saved for the ultimate pole climbing minibot.

[Mr. Rogers]

We placed an order for about 10 775's, about 3 or 4 of them had case shorts, we tested the ones off of our 2011 bot as well, 1 of them had a case short. This is a bunch of ##### @@@@!!! :mad: :mad: :mad: I don't want to re-inspect at Troy district and find continuity through our frame after the garabage motors have run in and shorted. Want to return them and go with FP's.

[Ether]

Want to return them

Let us know how that works out for you, OK?

[Mr. Rogers]

Probably not very well, 10 motors already mounted to CIM-ulator's is a heafty order to return.

[Cory]

Probably not very well, 10 motors already mounted to CIM-ulator's is a heafty order to return.

It's banebots problem, not yours.

I'd scream bloody murder until they not only took them back, but sent you a UPS/USPS/FedEx label for the return.

[Jim Wilks]

It's banebots problem, not yours.

I'd scream bloody murder until they not only took them back, but sent you a UPS/USPS/FedEx label for the return.

Banebots has a large history of not listening to any of us. How do you change that?

[MrForbes]

Simple, don't buy anything from them.