BaneBots Shorted, Now What Do I Do?
 

I've got a fairly large problem. My shooter subteam came to me today and said that one of their two BaneBots 775s burned out. This was in their attempt to construct a working shooter (they've never succeeded in making a functioning shooter thusfar). After perusing ChiefDelphi, I can see that
BaneBots shorting is a common problem. So where do I go from here? I have several options:
A. Attempt to fix BaneBot motor.
B. Order new BaneBot motors (their shipping lag is currently around six days, and this also shares a problem with option A in that I don't know if the shooter will even work once they actually assemble it with BaneBot motors).
C. Redesign shooter to accomodate different type of motor. Another team recommended using FP motors, but those are both currently in use by our ball conveyor belt.
Our current shooter design looks very similar to iR3 Creative's rectangular shooter system. Is there another option here I'm not seeing?

I'd really appreciate some mentors weighing in, because I have no adults to consult with. We're now rather short on time, and I need some experienced opinions on what the fastest way to get a working shooter is. It doesn't have to be the world's greatest shooter, just something that's reasonably effective. Thanks in advance.

Re: BaneBots Shorted, Now What Do I Do?
 

RMA to BaneBots.

There is a temporary fix, however--12V from the lead to the case.

I assume that you've seen this thread; there is a wealth of information in it: http://www.chiefdelphi.com/forums/sh...ad.php?t=91733

But, like I said, contact BaneBots immediately and let them know there is a problem. They may have procedures for returning/replacing.

Re: BaneBots Shorted, Now What Do I Do?
 

Have you tried the am-9015 motor (andymark p/n am-0912)? It has very similar characteristics to the FP motors, and you should have received one in your kit.

Re: BaneBots Shorted, Now What Do I Do?
 

What is RMA?
Return Merchandise...something?

Re: BaneBots Shorted, Now What Do I Do?
 

Something like that. It means that you contact the company and do what they tell you to do to return/repair/replace the product.

BaneBots has come out and said that they shouldn't be shipping anything with a case short. If you get something with a case short, then they would love to know about it, even if they don't replace it (and I think they probably will replace it, but I'm not sure about that).

Re: BaneBots Shorted, Now What Do I Do?
 

Did the shooter sub-team discover a case-short problem, or did their prototype actually smoke/burn out the motors?

While the RS775 motors have had a history of case-shorted issues, it's also entirely possible the shooter prototype overheated/smoked the motor. This is likely if the motor was stalled for some period of time, or if the prototype gearbox/motor mounting blocked the front vents on the 775 motor. All of the 500- and 700- series motors in the KOP (Banebots, FP, AM) have front air vent ports that must not be blocked or the motors will overheat and die.

Re: BaneBots Shorted, Now What Do I Do?
 

Can you elaborate on this? I'm not sure what you mean. I tried running 12V from a DC power supply box and got no current.

Re: BaneBots Shorted, Now What Do I Do?
 

They say there was no smoke. i can't imagine what would have stalled it- it was just in a gearbox.

EDIT to say that it was in an official, unmodified BaneBot gearbox.

Re: BaneBots Shorted, Now What Do I Do?
 

It's early in the thread I linked to--you short a lead to the case with something like the battery, then repeat for the other lead. Be warned, though, that teams doing this have reported problem recurrence and reduced performance.

Re: BaneBots Shorted, Now What Do I Do?
 

Willing to try that, but it sounds extremely unsafe. Any way to reduce risk?

Re: BaneBots Shorted, Now What Do I Do?
 

This is how we fix them....

http://www.youtube.com/watch?list=UU...&v=zpxolE76bZw

Re: BaneBots Shorted, Now What Do I Do?
 

Return Material Authorization.

You seek (and hopefully get) authorization from the supplier to return the defective material for repair/refund/replacement.

Re: BaneBots Shorted, Now What Do I Do?
 

Also, also, Banebots does ship thing out quicker than 6 days. Gearboxes take 6-ish days to ship, but we just got a shipment of gearbox parts and bearing blocks that shipped out in 2-3 business days.

Re: BaneBots Shorted, Now What Do I Do?
 

The unsafeness is how it works. I suggest wearing thick gloves and safety glasses, naturally. There might be a big spark if you indeed do have a case short, so be prepared for that. You might also get nothing at first, in which case you might have to have someone else rotate the output shaft until you reach the short again.

Re: BaneBots Shorted, Now What Do I Do?
 

In deference to Eric et al..

Please do not use the 12v unlimited current from a tab to case to clear (burn open) the RS-555 armature short!!

Justification is The theory of a metal flake causing the short is flawed.

I have examined lots of 550 shorted case failures at multi Regionals & championships, none had a metal flake. All had armature winding short to the metal armature at the turn around (sharpest point). None had evidence brush holder to case debris. Post test cleared the brush holder every time. Every short traced to contact to case via rotor, thru end bushings bearings.

A metal flake is highly unlikely to cause a short to CASE! wire is enamel insulated
so such a short would need to be in the brush holder tab to case in which case it would easily shake out!

The HARD short of the armature winding is another story.

It is caused by mfr relying on epoxy insulation + enamel on wire, rather than customary brown fiber covering sharp iron ends so tight wraps have a buffer.

Done to maximize copper window in small armature winding areas + save $.

Check out CIM armature brown fiber insulation use to effectively eliminate this failure mechanism.

As motors become smaller mfrs seek alternate methods like omitting fiber barrier.

Enamel wire tightly wound over sharp cornered steel laminated in 550 armatures has extensive history of high short to case fail rate. high as 50-70% new out of boxes at Regionals where I was RI in 2011 going back to 2010

Burn open short clearing is not only DANGEROUS but also BAD fix. :ahh: :mad:

12v ~800A: blows apart offending single wire short armature to case ~debris?

This disables one armature pole reducing motor power plus asymmetrical excitation. Not something you ever want to put back into a competition robot!

Also it may set up a condition of intermittent dynamic to case continuity!
..cause now you have two burnt loose copper ends free to flip around.

In improperly geared CIM's I've observed a similar gradual degradation where too high a gear ratio combined with heavy throttle by driver pushing opponents etc keeps CIM at High current, low torque part of curve too long.

Much self heating results weakening copper wire bond to commutator.

Subsequent High RPM force causes wire to detach, fly off, or high current burnout from concentrated current density in a short work weakened copper (bending back & forth), opening a pole on the armature.

The degraded motor still starts up & spins with remaining poles but at greatly decreased performance and not so smooth anymore! (& lower start-up & running torque due to lost pole)

Hint Perform Destructive Failure Analysis of failed motors as a class exercise to gain better understanding of what happened to apply forward. (destructive = observe closely then unwind the rotor carefully inspection as you go for problem areas (wire may break as you unwind). Take close up photos when you find a 'smoking gun', document in daily log pics & text description + hypothesize why/how it happened, then publish results.

Good luck.. all teams going with RS-550's again this year!!
Stock up on pre-tested open spares if you need capability it serves!
The Spare Parts will run out of their limited replacements EARLY!

Teams NOT using their RS-550s please Graciously bring them to regionals
to turn-in to Spare Parts to help your fellow competitors!!

Re: BaneBots Shorted, Now What Do I Do?
 

I thought we had a case shorted RS775, the motor ran fine for break-in, and for a while after that during testing. Then it seized and popped the fuse we had in-line. After taking the case apart to investigate (a problem I have had since a young age::ouch:: ) I discovered the culprit to be a common paper staple had gotten between the magnets and rotor. I removed the offending staple and reassembled the motor, and it works, but now there is some endplay in the shaft. On a side note these motors were shipped strait to our shop, and used only there (we do not have paper staples in our shop) everything is in three hole binders.

Re: BaneBots Shorted, Now What Do I Do?
 

For some reason I thought that was legit. Why am I surprised to see that happen? :p

Re: BaneBots Shorted, Now What Do I Do?
 

Dale(294engr],

Correct me if I am wrong, but you mention the RS-555 and RS-550. I was under the impression that the failures and case shorting was common place for the RS-775, and that the RS-550 has been a realitively good motor in the past.

Re: BaneBots Shorted, Now What Do I Do?
 

I've only heard complaints on the RS775-18, even; though when a non-FRC application was talking about using the RS775-12 I did suggest that they check for the case short just to be on the safe side.

Re: BaneBots Shorted, Now What Do I Do?
 

QUICK FIX: CIM MOTOR. Nuff' Said.

We recieved our RS-775 motors and have despite all the forums saying they suck and never use them. We love them haha.

But to answer this forum. If replacing/shipping is an issue, maybe order another, or just replace is with a CIM motor.

2 CIM motor drive is just fine, unless you were trying to with with a mech. drive. otherwise if you are going with a 6-8-10-12-16 wheel drive, 2-3 CIM motors will serve just fine.

Re: BaneBots Shorted, Now What Do I Do?
 

The motor cannot be fixed, the shorting method can keep it running for a little while, but the motor will be weaker and will soon fail again.

BaneBots' lead time is shorter if you don't get a gearbox. If you contact them directly about your failed motor, they might be able to ship out a replacement even faster.

I would recommend replacing the motors with BB550s, FPs, or am-0912s. The FP and AM, except the the 0673, more closely match the speed of the 775s, making them better candidates for drop in replacement, with the FP 9013 being the closest in power. The motors on your lift could be replaced with AM or BB if you need the FP on the shooter.
It sounds like you're using P60 transmissions, am I right? If so, only the block that the motor directly attaches to needs to change. If you have access to a mill, you could redrill mounting holes that have the right spacing, otherwise you could buy a 5xx mounting block or find a local team who is willing to loan or donate one to you.

Re: BaneBots Shorted, Now What Do I Do?
 

RS775-18 273 watts

FP 0673 292 watts

FP 9013 209 watts

Re: BaneBots Shorted, Now What Do I Do?
 

He was using Price is Right rules. "Closest without going over." :D

In all seriousness, I would absolutely contact BaneBots about a possible replacement and avoid self-fixes. Remember that if you open the motor (take off the case) it is no longer competition legal.

Re: BaneBots Shorted, Now What Do I Do?
 

Closest in power between the ones that I thought were a good choice based on speed. Going with a FP-0673 or BB550 would more likely need a gearing change.

Re: BaneBots Shorted, Now What Do I Do?
 

It depends on how the motors are being controlled. You could make the 0673 "look" like a 775-18 by running it at a lower voltage to get the same torque and speed.

@dexo568: How are you controlling the motors?

Re: BaneBots Shorted, Now What Do I Do?
 

Is this a problem with Banebots RS775-12's, or does it also affect the RS775-18?

Re: BaneBots Shorted, Now What Do I Do?
 

The problem is with the RS775-18. Not sure about the -12's.