Cooling motors?

Back a few months ago during my state competition, another team was having a flywheel motor that liked to overheat. (5-10 seconds) They asked me for a quick fix. So, as the jerry-rigger that I am, I took a scrapped piece of aluminum 25 c-channel that was lying in our parts box, flattened it out, put a bunch of screws on it, and attached it to their motor with zip ties. * The method behind the madness was to contact the motor with a metal with high thermal conductivity (aluminum) and to spread that heat over a large surface area (screws) so that air passing over the unit could cool the motor. To my surprise, the cooling unit worked well enough that the team could run their flywheel nonstop for the entire match without overheating. So, I pass this idea onto you guys. What do you think? Is it worth it for motors with high stress such as on a dumper? Any improvements? Legality?

We (until recently) resorted to using a compressed air cylinder upside down to cool off the motors really quickly. However, the heat sink idea does sound really interesting if it is a serious problem for your robot. Luckily we haven’t experienced any stalling problems (probably due to a way-too-high gear ratio…), but I can imagine that this solution would be the perfect bit of genius for some teams. Great idea!

Thanks! Now, does anyone know about the effects of heat on motor performance? I’m wondering about what would happen if you put heat sinks on every motor – would the extra weight be worth the power?

Just gonna say, if you’re motors are overheating, then you’re probably already drawing too many amps. So if you don’t trip the thermal sensors in the motor, you’re just gonna trip the PTCs in the cortex. Just another point of failure.

To be honest I can see this having very little actual impact. If you could contact the actual motor with a heat sink it would be a different story. The “Motor Module” has so much air around the actual motor that the heat transfer to the plastic casing is minimal.

I came to this same conclusion when we were having overheating issues with a couple of our motors last season. Plastic is a terrible heat conductor and the things you need to actually cool are inside the motors - not touching the plastic casing. So I concluded that the use of a heat sink would not be effective. However, if they proved it in practice, maybe there is something I was overlooking…

I think this would be an excellent engineering project for some high school kids to work on. Open up a motor, place some tiny thermal sensors inside the motor housing and/or use the motor’s PTC circuit to monitor temperature, and run some tests to get some idea of the motor’s thermal transfer characteristics. The results could finally solve the debate over whether or not doing things like spraying a motor with liquid air, mounting C-channel heat sinks, etc. actually help at all.

At least in the one very narrow and specific situation (needs way more research to be considered viable) I tested this in, the motor casing itself was very warm on one side. Perhaps there was something different about this motor in comparison to most other ones.

Great idea! @Mr_L_on_Yoshi

Can of compressed air upside down on the motors before you use them. Works well too

Compressed air is too overkill
at competitions i use a Hyper 212 EVO:
https://dl.dropboxusercontent.com/1/view/442eikeeq1y4zez/Apps/Shutter/motorcooling.png

In all seriousness upside down compressed air is the fastest way of cooling motors, but you should probably reduce friction before resorting to that because compressed air gets pretty expensive when you use it constantly

using aluminum as a heatsink is a pretty good idea, just make sure its flat with the surface of the motor casing because the parts that are not in direct contact have zero affect