[Joe Johnson]

Paul, et al,

How certain are you of this F-P spec?

PEAK POWER: 400+ Watts!

Whoa... ...that's a lot of power. That means that the F-P motors are easily the most powerful motors in the kit. The Chiaphua's (a.k.a. CIM's) are something like 300-350W as I recall.

For those who do not have experience, if you are planning on using anything close to that amount of power, you had better be sure to leave the vents on the front end of the motor open to breath. There is a lot of heat to get out of a small space. Even with the 150W motors from prior years (again from memory not from specs), we used to melt the fans off the armatures. I think we had 200+W motors in 2002 but nothing like this.

Interesting. What was the spec last year -- my memory fades.

FYI PEAK POWER in Watts = (FreeSpeed in RPM) * (Stall Torque in N-m) / 38

This is a useful figure of merit for motor power -- the 1/38 comes from the fact that the peak power happens at 1/2 the stall torque and 1/2 the free speed and that RPM to Radians/Sec ~ 1/10

On another note, the Dewalt whitepaper (see plug below) that explains how to use the F-P motor in a Dewalt Transmission, does not open up these holes. It is possible, even without a mill to leave these holes open. If you are going to drive with a F-P motor, you should definitely open the holes*.

Joe J.

*they are already open on the standard transmission, I really mean this as a note to those who are planning on making your own transmission for these motors -- it make a huge difference the cooling of your motor -- don't be fooled by folks who put fins on the outside of the motor can. While this can be good to improve the amount of power you can put in these motors for long periods of time, FIRST matches are not "long" in heat transfer terms. To give you a perspective: A curling iron is typically 20W. At stall, you are pounding 150Amps at 12V -- that is 1800W of power -- we are talking blowdryer's here. There is just NO WAY you are going to conduct that amount of heat way with fins on the outside of a motor can. You need AIR FLOW to carry that heat away. While I am at it, once you get to stall, there is no way you are going to even blow that much heat away because a stalled motor is not blowing any air!

One final thing, don't tell me that the 40A breaker is going to save you either. This as been discussed 10s fo times on this sight - search "40A breaker trip time" (in fact I just did and there was a lot of talk of burning up F-P motors -- checkit out). You will discover that the 40A breaker can conduct 2 and 3 times their rated current for significant periods of time before they open.