Does motor temp affect performance?

[Joe Johnson]

Originally Posted by thefro526

<snip>
Is there a noticeable performance gain by cooling motors like this, or is it just a good preventive measure? I was always told that cooling the motors in such a way could damage the motor, but your post has sparked my interest. Maybe I'll pick up a can as an experiment.

<snip>

This effect is real and measurable. In automotive applications, it is often the case that a motor at -40C breaks the actuator because it has more power/stall torque (and the plastic is generally more brittle).

As to FIRST, the cooling effect of Freez It is fleeting in that you do not have an infinite sink of -40C to draw from so your motors get hot eventually anyway but if you start warm, then get warmer, then start warmer get hot, then start hot and get hotter, then start hotter and get boiling, you are fighting a loosing battle.

If you can keep your motors starting a match at just warm or warmer then you can keep from overheating by the end of the match (potentially).

The problem with a brushed DC motor like the CIM is that it is totally enclosed. All of the heat is generated in the windings of the armature. How does that heat get out? Well, a little is conducted away via the shafts and a little is convected away via the air inside the can but that air has to then re-convect (if that is a word) the heat back to the inside surface of the can of the motor for it to be conducted away to the outside of the can and then convected away by the air outside the robot.

All this takes time. If you have time, all is well, but if you don't (as in the elims) the heat builds up.

If you open the can of your motors, you are likely going to smell something that to this day makes me ill, burnt motor insulation.

By the way, your gear ratio is probably not high enough but that cake is already baked. From what I saw of you at the MSC, you guys are doing just fine with the too tall of gearing you have. You just need to make sure your motors are cooled down between matches and you'll do fine -- next year, consider a bit more ratio ;-)

Joe J.