fans on victors

[Al Skierkiewicz]

Boy,
I get busy for one day with FLL and the forum runs amuck.
Here is the whole scoop. Fans on victors are not required by FIRST but IFI wants to see them and that's why they are provided. From the 884 user's manual...
1. The fan must be wired so it is always ON when the Victor is ON.

and

The innovative FET switching architecture and an integral cooling fan ensures cool FET junction temperatures.


The FETs are rated at 64 amps each, for three in parallel that is 192 amps. But this rating is at 25 degrees C. As the temperature rises, the current must be derated such that at 100 degrees, each FET can only handle 45 amps for a total of 135 amps. Now seeing as the Chalupa motors (small CIM) have a stall current of 133 amps and with the derating factor of 135 amps at 100 C (remember that max allowable current goes down as the temp rises) if you want to live dangerously, then leave the fans off. Please don't be our alliance partner on Einstein.

As for weight, the Victor is only 4 oz total. The fan cannot be so heavy that it would mean the difference in meeting weight or not. A similar fan is speced out by the manufacturer at 1.25 oz or about 22 3/4" holes in aluminum box tube.