Record Player Speed Changing

This LOOKS like it might work well, but it won't. ANY added resistance to the drive power will make a shaded-pole motor increasingly load dependant. Another name for a shaded-pole motor is a "synchronous motor". This is because the speed of the motor is synchronized with the 50-60 Hz of the line/mains frequency. It remains synchronous, by the virtue of the power supplied being able to overcome the work it is called to do. For instance... If you have a synch. motor that is unloaded, you can put a fair amount of resistance in the power line and not effect the speed to a great degree. But in that circumstance, add a small load to the motor the speed will drop considerably. To remain synchronous, the power cannot be reduced below it's ability to maintain rotational speed. The synch motor is tuned to the required speed, by the ratio of the windings in the armature. Such that the reflected current from the armature coincides with the magnetic field of the incoming current from the stator. Yes... You can reduce the speed of the motor by reducing the drive current, but the motor's speed will loose its synchronous ability and become very unstable due to load. This is why a record player equipped with such a motor, changes the required speed by altering the diameter of the drive shaft.

The reduced current on A.C. half -cycles allows larger motor slip angles. Two ways to control motor speed is more load or rotate motor field with electric circuit. Speed is smoothed out with turntable, rotor inertia, and record with needle drag. "How It Works" is at POPULAR ELECTRONICS, August of 1956, on page 89.

As I said, yes you CAN change the speed of the shaded pole motor by adding resistance in the drive circuit. However, it is a very bad practice and bad engineering, to do so in the world of devices requiring absolute speed stability, such as a record player.

"Speed is smoothed out with turntable, rotor inertia, and record with needle drag." / The synchronous motor's best chance of providing a constant speed, is to maintain adequate drive current to the motor. Anything less is to induce poor performance. Unless poor performance is the goal.