Check the current draw of the fan motor. It pulls considerably more amperage than the clutch coil and worn bushings in the motor can cause the armature to drag and prevent the fan from coming up to normal speed. A slightly stalled-down electric motor will pull huge amounts of current because the windings don't develop the "counter EMF" required to limit its current draw. That's the same reason that continuing to run a starter after the battery gets a little low can destroy both the starter windings and the battery.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!