Thermal Compound for PCs?

[Arct1k]

Originally Posted by brijar

I have a heatsink on my Mamba Max 5700 motor in my Rustler and the heatsink always gets hotter than the motor, so I assume it is doing its job.

Not really possible without a heatpump - Only suggestion is motor had cooled down and residual heat was in heatsink... This is difficult to imagine as the heatsink should be radiating more that the motor.

Only one final thought is that the heatsink was "radiating" more than the motor and fooling your temp gauage.

[BrianG]

Originally Posted by Arct1k

Not really possible without a heatpump - Only suggestion is motor had cooled down and residual heat was in heatsink... This is difficult to imagine as the heatsink should be radiating more that the motor.

Only one final thought is that the heatsink was "radiating" more than the motor and fooling your temp gauage.

Or it could be the color and/or composition of the heatsink has a different emissivity rating than the motor. IR thermal probes are somewhat sensitive to that setting, which is why you are supposed to set the emissivity to whatever material/color you plan to use the most.

This a really good question. I'm a bit of a nerd also, so when I did my E-Revo I slathered the RCM heat sync with cpu thermal paste. Didn't even think twice lol.

Anyway, I'm probably geared wrong as the esc and batts are getting barely warm, but the motor gets to about 70C after about 5 min of race style driving. The bottom part which is uncovered by the heat sync is much hotter than the actual heat sync itself.

The RCM sync is REALLY snug tho. I took it off after the first few runs to make sure there weren't any air bubbles and found that it was fine; I only put a very thin coat of paste on so was quite happy.

CPU paste isn't generally rated much above 60C tho, so I'd imagine that mine will be useless in another few runs; it'll all harden up and stop conducting the heat away from the motor. Might see if I can find some non cpu paste.

[brijar]

Regarding my last post, I just realized that since the heatsink covers all the available can, I have no way to tell if the can is getting hotter than the heatsink, so I just feel the back plastic part of the can, which is always cooler than the heatsink. I also check the temp of the pinion gear, which is usually pretty cool, though I'd think it would get hotter than the can itself.
The motor rarely gets above 160*F, and that's running 15/90 with big Talon tires a wad of metal to extend the chassis (so that the beautiful Desert Rat body will fit) and 4s A123 doing high speed runs up and down the street.
Just thought I'd clear that up.

Brijar!!!