Caution - Burned out CIM blows Victor

[Mark McLeod]

Originally Posted by Ether

Could you please elaborate on this statement? What is free, and why is it free "due to the RMA policy" ?

TI will replace Jaguars that fail.
RMA procedure: http://forums.usfirst.org/showthread...7077#post37077

TI issued a failure report based on the Jaguars that were returned to them last year.
If anyone has a failure, TI would like to get them back for analysis and we'll all learn what's going wrong.

We can use last year's report as an aid in evaluating the Jaguar's part as one of the components in an electrical problem.

[Ether]

Originally Posted by Mark McLeod

TI will replace Jaguars that fail.
http://forums.usfirst.org/showthread...7077#post37077

OK, my bad. I missed the context. Thanks.


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[Al Skierkiewicz]

Originally Posted by Ether

Nice summary Al, thanks. Minor point: I think you meant "conduction" not "convection".


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Correct, I was thinking of two or three things at once, just ending a curious day at Wisconsin regional.
I wanted to add that the breakers may have been tripping but without actually observing this once, it is hard to recognize especially on a loud robot. The breakers reset almost immediately and with a sustained short may actually buzz. Most everyone is so caught up in the other things going on that the buzz is the last thing that grabs their attention.
As to hi pot testing, I am not sure that would catch a failure until it becomes a disaster. A few shorted windings may not indicate any resistance drops to the motor frame. By the time the damage was done, the motor was already very suspect. As Ether has point out, a milliohmeter or bridge would be the better choice but with production variances, you might find significant differences from several good motors.
For everyone else, the CIM motor is not an easy motor to disassemble without damage. Once you pull it apart, you might damage it beyond hope. If you suspect a bad motor or one that is very hot in use, try removing one of the screws that hold the motor together. Smell the screw and the hole in the motor. The burning smell is distinctive and if things are bad the screw make actually show signs of contamination from the damaged windings.

[NyCityKId]

has anyone considered a growler test? its a piece of test equipment thats used to test for short (and im assuming damage) in motor windings. they uses it in the airline industry but im not sure if its main stream equipment

[Ether]

Originally Posted by NyCityKId

has anyone considered a growler test?

It is not permitted to disassemble the motor.


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[Damaku250]

Originally Posted by JesseK

Interesting information. I wonder how the jags respond to this, given their internal fault protections. Really I just want to know so if something weird happens electrically we don't immediately blame the Jaguar.

Fairly sure we've shorted a CIM just before the finals at WAT, costing us the quarter final match. Only thing noticeable about the Jag was that it seemed significantly hotter than all the others and stayed that way longer, while the others had already cooled. I'm concerned, should we replace it?

Does any one have any ideas on how a rookie team like us could diagnose the health of our remaining motors to ensure this doesn't happen again? (short of disassembling gearboxes to determine how the motor sounds)