What kind of motor is in ceiling fans?

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tornitore45
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What kind of motor is in ceiling fans?

Post by tornitore45 » Fri Mar 23, 2018 11:15 am

My search on the web indicate the speed is varied by a number of techniques aimed at changing the voltage. Series impedance or specialized dimmer that cut the sine-wave.

All fan motors look to me like single phase induction motors which are known to be controlled by V proportional to Frequency and just changing the voltage is not an effective method.
Mauro Gaetano
in Austin TX

John Hasler
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Re: What kind of motor is in ceiling fans?

Post by John Hasler » Fri Mar 23, 2018 12:00 pm

The torque required to spin a fan is proportional to the square of the speed. Thus reducing the voltage to an induction motor driving a fan results in the motor stabilizing at a high slip rather than stalling as it would with a constant torque load. The speed control isn't very good, but it's good enough for the application.

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Atkinson_Railroad
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Re: What kind of motor is in ceiling fans?

Post by Atkinson_Railroad » Fri Mar 23, 2018 4:05 pm

Ceiling Fan motors are typically either Shaded Pole, or Permanent Split Capacitor motors.
The speed of both types can be controlled by adjusting the applied voltage.

Single Phase motors are named for the way they start.

John

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