Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

So far, no problems for us.

-Nick

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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...

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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?

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

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

Re: Banebots RS-775 Case Short
 

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.

Re: Banebots RS-775 Case Short
 

Did what you asked and we are still good to go

Re: Banebots RS-775 Case Short
 

Well <r47> states

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

Re: Banebots RS-775 Case Short
 

~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.