Brushless motors

[Tdog]

I'm having a bathroom redo & the new light-fan-heater units are listed as 'brushless' motors. We noticed that the fan starts very slowly - - is that a characteristic of that type electric motor? I'd never heard of brushless motors but understand they are very efficient. Just wondering about the start-up issue.

Thanks,

Jack

 

[Mace Canute]

Probably a small shaded pole motor. They have (almost) zippola for torque at stall but that slowly increases as their rpm builds and yes, they are slow starting compared to other electric motors.

SP motors are very well suited for fan duty since starting torque on a fan is no more than inertial load and they are dead simple in construction, only one winding...no moving parts except for the rotor...no capacitor, no start windings or start switch...just a couple of "bearings" that tend to be cheap bushings.

 

[BobRip]

I think these are brushless dc motors with electronics to bring the speed up slowly. This is typically what they mean by brushless. The older fans used shaded pole motors.