[dtengineering]

A good comparison between the FP and the CIM might be like the difference between a turbocharged four cylinder engine in Cobalt SS and the turbo diesel in a Mack truck. They are both rated for about the same horsepower, but the SS needs to run at an extremely high rpm to get that kind of power... the mack truck can churn it out day after day after day.

So I tend to use the CIM in "mack truck" applications, where low rpm and continuous hard pulling are common, while I tend to use the FP's in high RPM applications for shorter periods of time... race car applications.

I have found that while CIM's can handle pretty much all the current you can throw at them for a two minute match (and will pop the 40A* breaker before you damage the motor) that an FP is happiest at about 10A or less. Sure, they CAN draw more... but for a very short period of time unless there is some truly awesome cooling going on.

So if you are going to use an FP in any kind of torquey application, make sure you have it massively geared down (the Banebots gearboxes work great for this, you just need to press a new pinion gear on to the FP) and don't run it near stall (for instance, holding an arm in one place). When you stall it you keep pumping current through it (generating heat), but lose all the cooling from the fan mounted inside the motor. You might also want to consider strapping on an auxilliary cooling fan, a heat sink, or... (and I haven't done this, or seen it done, but it might work) having a small pneumatic line set up to blow a bit of compressed air into one end of the motor. It may also be legal to attach a bit of dry ice to the FP right before a match...

Jason

* when dealing with a short time frame... continuous current draw of even "moderate" (for an FRC application) current will heat up the motor without even coming close to tripping the breaker... we almost got into trouble in Seattle this year when we were able to play four practice matches in a row. GREAT for the drive team to get practice, but the motors were very warm to touch when we got back to the pits.. and if the motor is warm on the outside, that means it is HOT on the inside, and the heat just hasn't made it out yet.