Change out Overheating Motor?

I’m not sure if this is the right place to post this - but here goes…

We have one motor that tends to overheat by the end of qualifications. We have tried keeping it cool throughout the tournaments with little success. If the team swaps the motor out for a fresh motor, will that eliminate the overheating problem? Has anyone seen/used this as a viable strategy to keep motors from overheating?

The reason I am asking this is because I don’t know what the contributions of the motor controller or microcontroller are in the whole overheating process? Is it just the motor or other elements involved…?

What is this motor used for? Do other motors on this same system burn out?

When you say “overheat” you are actually experiencing a PTC trip. The motors have PTC’s that trip if the motor gets too hot and the cortex has 2 PTC’s (ports 1-5 and 6-10) that will trip if too much amperage is being drawn. You can mostly avoid the Cortex PTC’s by balancing out each system to have the same amount of motors on each side per system. The motor PTC just requires tuning to make sure you are not pulling too much current in a short period of time. Reduce friction.

It is for our “striker.” The motor is used to pull the striker back and is the only motor used (we get a full cross court shot with one motor). So it is under a fair amount of strain.

Cyber brains: It is only one motor and after we wait around 5 seconds, the motor works again (for a short period of time). No other motors on the robot are impacted (not apparently, at least).

You are most likely experiencing a motor ptc tripping… What kind of motor is it? ie torque, turbo, speed

Thunder: so if that’s the case, replacing the motor would fix the problem…?

It could be, if you have an extra torque motor laying around I would try it. I heard once that the more you burn out a motor, the easier it gets to burn it out

Correct me if I’m wrong, but if the PTC fuse in the motor is tripping, then it’s not ‘burning out’ as such; the PTC fuse shuts off the motor once it reaches a certain temperature in order to prevent motor burn-out. PTC fuses are made of a material that increases in electrical resistance as it increases in temperature. (PTC stands for ‘Positive Temperature Coefficient’. When motors heat up, the resistance of the PTC material increases until it cuts off voltage to the motor. Once the motor in general and the PTC material in particular cool a bit, the motors can run again, but if you don’t wait long enough, the temperature can still be close to the cutoff point, and just a little but of motor running can cause the fuse to trip again.

@Gear Geeks, how have you tried to keep the motors cool? In particular, I can recommend using cold-spray (like this) to quickly cool down motors, especially if you have two matches close together. A short burst on the motor casing does the trick pretty well in my experience. You can also use an upside-down can of canned air (for cleaning keyboards; available at office-supply stores). Of course, swapping between a couple of motors (using one motor while the other cools) will probably work too.

For some reason, I’ve been nervous about using the cold spray. I’m worried that spraying really cold spray on a hot motor could cause cracking or other problems. We bought a couple of fans and have been just blowing them across the motors in between matches. It has not worked well. Maybe I should bite the bullet and try the cold spray.

The first time that I used a cold spray I thought the same thing but after 2 and a half years using it for my team and my friends team we have never had a problem with it.

Trex: Good to know! Thanks!

On the other hand, if possible use two motors rather than one and run each at about 80-85% power.