[dtengineering]

It has been years since we've put ventilation fans on our CIM motors. The only time we've missed them was during practice rounds for Overdrive when there weren't many other teams ready to go and the tournament organizers wanted a full field of robots to test the field. I think we played four or five full matches in quick succession, pausing once to change batteries, before we finally pulled the robot off the field because the motors were getting a bit too warm and needed to cool down for a while.

We've also heated the motors up in the shop during build (I recall once when we weren't paying attention and let them get too hot using a bit of carefully packed snow to cool them down so we could drive again... now we use an IR thermometer from time to time and try not to let the outside of the case get too hot... I think it is somewhere around 40-50 degrees that we shut them down...), but we never have we been able to make the CIM's get "too hot" in a qualifying or elimination match.

The FP's, however, start to heat up really quickly if you don't keep them moving at a fairly high speed. We built a heat sink for our Aim High ball shooter, which ran at around 10 amps (and could keep it up for most of a match) but we also make a point of only running the FP's off a 20amp breaker, and monitoring current use carefully (clamp on ammeters rule!) during build. We prefer to keep the FPs drawing under 5amps. Some teams have come up with quick and simple ways to strap a small fan on to their FP using zap ties, and it probably helps a bit.

So if you don't see teams using the cooling fans, it is probably because they aren't really necessary, consume a bit of current when the robot is running, and add weight that doesn't contribute to the overall success of the robot.

Jason