Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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?

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

.....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?

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

This looks like the same motor to me.

Re: Banebots RS-775 Case Short
 

http://www.chiefdelphi.com/forums/sh...7&postcount=13

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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?

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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 listed Mabuchi as their manufacturer, but rather a variety of Chinese companies.

Re: Banebots RS-775 Case Short
 

Art explained my thinking, thanks Art

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

-Brando

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

Mabuchi has 4 factories in China.

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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...

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.)

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

2011 F-P Motors and associated gearboxes and motor-cap products are now available.

Thanks for your patience,
Andy

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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?

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

See http://www.chiefdelphi.com/forums/sh...t=781+Einstein Paragraph 7 for an explanation of our unfortunate luck on Einstein 2011.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

Yeah, seriously.

I don't get the analogy.

Re: Banebots RS-775 Case Short
 

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. :)

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

WE have 550 sized motors from FP and AM.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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
...........

Re: Banebots RS-775 Case Short
 

http://www.chiefdelphi.com/forums/sh...9&postcount=74

http://www.chiefdelphi.com/forums/sh...4&postcount=82

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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? This might be legal if either:

1. Both types of 775s were provided to various teams in the KOP; or
2. The "acceptable part numbers" part takes precedence over "the BaneBots motors provided in the KOP".

Re: Banebots RS-775 Case Short
 

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 (yup, I'm biased ;)), as shown below:

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

rather nice prototype you got there!

Re: Banebots RS-775 Case Short
 

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.)

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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.