Shaded pole motor

[Wytnucls]

220VAC 50Hz shaded pole motor.
I understand the principle of operation of the motor, but what seems strange is that I can generate a small AC voltage in the winding by turning the rotor by hand (15Hz 170mV).
Any idea how this works?

[Yansi]

Simple. remanent magnetization trapped in the rotor.

http://en.wikipedia.org/wiki/Remanence

[SeanB]

The same thing with the original car generator, where the remnant magnetism in the field winding is what starts the voltage generation when you start the car. This then gives the initial voltage required to pull in the charge relay to start charging the battery. That is why you have to briefly short the F terminal to battery positive when converting the car from positive to negative earth, otherwise it will start out with a negative voltage generated, and when the regulator connects it to the battery it will flatten it very fast.

Also used with making 3 phase generators out of an induction motor, you typically will have to place a slight magnetic bias in the rotor by passing a high DC current through one winding if there is not already a bias present from manufacturing or use.

[Wytnucls]

Thanks. Doh, should have thought about it.
Now I understand how this free energy works: 

[SeanB]

Note where he brakes the rotors the light goes out just before. I will guess there are 2 48SWG wires leading off to the sodes to provide the AC power to the system, hidden by the low resolution camera and the background. Switch off then brake, and you can see the RHS stopping slower as it slips on the rubber band.

Bet both of those shading rings were hot as well.

You saw Dave in his unboxing video with the 2 steppers doing the same by connecting the stepper wires, to make a simple selsyn system.