Shaded - pole electric motors are used on record players and other devices. This is speed adjusting circuit for those motors. Top switch is original 78 rpm record speed. Adding the 48 rpm is second switch and bottom switch is 33.3 rpm is new improvement. These three switches can be rotary switch on project to change speeds on the go. Bottom 10 mh coil is motor. Lamp is to run simulator. Top diode is 115 volt, 100 ma. selenium rectifier. Two adjustable resistor are 10 watt 300- 500 ohm adjustable wire wound resistors with two sliders. Set bottom switch on, adjust right slider first, it is 33.3 rpm speed. Next, turn on middle switch to set 45 rpm speed with left slider. If bottom slider is reset then adjust middle slider again.
How to set right rpm? Stroboscopic disk with strobe light is how the speed is set. www.keystrobe.com is one source to calibrate turntable speeds. I had been wondering how to set turntables.
