Originally posted by dtm
re: original assumption...
This would always be *less* than full duty, in which case Ohm's Law (heat = resistance of FET X voltage) applies.[/B]
Original speculation went along lines of:
a) at full tilt, full current goes thru (= X amt of heating)
b) at partial throttle, only a fraction of current goes thru (=X/? heating)
Now appears that, at the high loads racing ESCs run at, the (C) heating-from-switching effect causes enough heat to overcome the lesser current going through and also (D) any FET's resistance is nominally rated @ 25degC, resistance rises as it gets hotter - catch22.
But at lower loads... the switch-heat effect must be lower...?
Hmmm...
(sigh... this would be a great topic for a uni paper. Pity we're all out in real world already, sometimes I miss those boozin' days.)