Modifying CIMs to implode?

[Max Lobovsky]

Has anyone tried any other modifications to help heat dissipation? Are there any places you can safely put holes in the casing to get some air flow inside?

[Adam Y.]

Originally Posted by dlavery

OK, so this question in the Q&A system has me intrigued:



The answer from FIRST has not been posted yet, but it has me wondering - is any team actually contemplating turning down the outer walls of the CIM housing? Does anyone expect to be able to remove any meaningful amount of weight without destroying the characteristics of the motor? This would seem to be a very bad idea in terms of maintaining the structural integrity of the motor, and a potential hazard. Or am I being overly conservative? Anyone have any thoughts about whether this should be/will be permitted?

-dave

The odd thing is that a teams has all ready done this. In fact this was the only arguement my friend had for saying this. I will ask him what team it is again though. I honestly feel it's a bit dumb but he said almost two pounds of weight can be lost. Anyway I feel it is a moot point because the question has been answered.

[Katie Reynolds]

Originally Posted by Adam Y.

The odd thing is that a teams has all ready done this. In fact this was the only arguement my friend had for saying this.

See this reply, in this thread: http://www.chiefdelphi.com/forums/sh...5&postcount=12

Originally Posted by Adam Y.

I will ask him what team it is again though. I honestly feel it's a bit dumb but he said almost two pounds of weight can be lost.

Two pounds?? As Ahecht pointed out in the above post, the weight loss was not very significant.

[Andrew Schuetze]

I am not going to test the rule or disrespect the advice of motor techs on this list. My follow up is in regards to the reported gain in radiational cooling by removing the black paint by sanding to the bare metal?

Our team has never modified a motor or mount but the comment about bare metal verses paint is of mild interest. Does this violate the rule or even the spirit of the rule? I would guess that one could even add paint to the housing as part of some color scheme on the robot...

[Al Skierkiewicz]

Originally Posted by Andrew Schuetze

I am not going to test the rule or disrespect the advice of motor techs on this list. My follow up is in regards to the reported gain in radiational cooling by removing the black paint by sanding to the bare metal?

Our team has never modified a motor or mount but the comment about bare metal verses paint is of mild interest. Does this violate the rule or even the spirit of the rule? I would guess that one could even add paint to the housing as part of some color scheme on the robot...

Andrew,
I think the rule is clear that removing the paint does not change the basic ops of the motor. But like I have said many times before, if the Chalupas (or any motor) are overheating they are a symptom not a cause. Hot motors indicate a problem somewhere else. Fix the problem. When the case of the Chalupa is hot, think what the temp might be inside at wire level.
When the case is too hot to touch, you have already sacrificed molten varnish to the electrical gods. There is no coming back from this abuse and no amount of external cooling is going to save the motor. The internal temperatures, melt the varnish insulation, run the lubricant out of the bearings, distort the armature plates and shaft, and breakdown the internal adhesives used to keep all the parts in alignment. Remember that the only conduction path from armature to outside world is the shaft and bearings. All other cooling is by convection or radiation which is a slow process.

[M. Hicken]

Originally Posted by Al Skierkiewicz

Andrew,
I think the rule is clear that removing the paint does not change the basic ops of the motor. But like I have said many times before, if the Chalupas (or any motor) are overheating they are a symptom not a cause. Hot motors indicate a problem somewhere else. Fix the problem. When the case of the Chalupa is hot, think what the temp might be inside at wire level.
When the case is too hot to touch, you have already sacrificed molten varnish to the electrical gods. There is no coming back from this abuse and no amount of external cooling is going to save the motor. The internal temperatures, melt the varnish insulation, run the lubricant out of the bearings, distort the armature plates and shaft, and breakdown the internal adhesives used to keep all the parts in alignment. Remember that the only conduction path from armature to outside world is the shaft and bearings. All other cooling is by convection or radiation which is a slow process.

i know this is off topic, but last year we had drill motors running to a custom gear box (like many other teams). After each round we had 2 of the 120mm fans blowing on the motors because they were almost too hot to touch. My question is, are the CIM motors as likly to get that hot? We are currently being held up by electronics problems, and we have no way to run one for 3 minutes and take the temp. Sorry if that was confusing, i know it was poorly worded.

TIA

[Cory]

Originally Posted by M. Hicken

i know this is off topic, but last year we had drill motors running to a custom gear box (like many other teams). After each round we had 2 of the 120mm fans blowing on the motors because they were almost too hot to touch. My question is, are the CIM motors as likly to get that hot? We are currently being held up by electronics problems, and we have no way to run one for 3 minutes and take the temp. Sorry if that was confusing, i know it was poorly worded.

TIA

It takes a lot longer for the CIM's to get noticeably hot than it does for the drill motors.

[dlavery]

Regarding the potential use of the Chiaphua motors as small space heaters, you may want to go back and read through this thread for some interesting observations. Within certain limits, you can expect the Chiaphua motors to experience a reasonable degree of heating during normal use. But at some point, "reasonable" becomes "way the heck too hot." The exact conditions under which this transition occurs is not precisely known, but passing the transition point is dramatic and irreversably damaging to the motor.

-dave

[S.Nickens]

If your CIM's are getting too hot, consider the obvious, your gearing is too low. If heat is a problem, the motors are working too hard. If you properly gear your drive train too run at the motors max RPM you should have no problem with overheating.
Good Luck!

[Cory]

I think you mean high... if your robot is geared low, it would mean it's very slow, which means it's harder to stall the motors, which creates heat.

Or maybe I interpreted what you're saying entirely backwards

[S.Nickens]

Originally Posted by Cory

I think you mean high... if your robot is geared low, it would mean it's very slow, which means it's harder to stall the motors, which creates heat.

Or maybe I interpreted what you're saying entirely backwards

I'm sorry if I mis-spoke regarding the gearing being too high /low. What I was trying to say is, if you gear your drive train to run the motors at max. RPM they are less likely to overheat because they are under less load. We competed in three regionals and the nat's and never once had a heat problem with the CIM"s Just trying to be helpful, nothing else.
Good Luck!