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Old 02-17-2012, 09:53 AM   #9 (permalink)
mans
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Quote:
Originally Posted by SentraSE-R View Post
The trouble with adding resistors to control fan speeds is you still waste essentially the same amount of power at low speed + resistors as you do at high speed sans resistors. Adding the rheostat or resistors, you won't save any significant amount of power.
I was concerned about this...
An electrical engineer is telling me resistors work by wasting off the extra electricity into heat.
if thats the case the motor would use 7 amps regardless of the control knob setting, as at full power none would be wasted to heat, and the lower you go the more is turned into heat...

but when u put an ammeter to the car you will see that power draw DOES go down when u turn down the control knob.

This difference between what I find in actuality and what the electrical engineer tells me is confusing.
can anyone shed some light on this one?
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