Electric motor

Electric motors in the era of Edison, Westinghouse, and Tesla were considered mysterous; followed by a long era of being a commodity. Now that motors are controlled by software they are the center of intense reseach.

There is much confusing and contradicting published material about electric motors. Also, motors bridge the skills of electrical and mechanical engineers as exemplified by the equation p = iv = Γ ω.

Even more exciting is that electric motors inherently rely on relative motion ( and so ultimatlely on the special theory of relativity). This is why the myth of AC and DC motors exists. A motor will have a power supply that is either AC or DC. The next physical distinction states is/are the stator and rotor currents AC or DC.

If both currents are DC, this is the classic brushed DC motor supplied by a battery.

If one is DC and the other is AC with respect to the stator and rotor ( does not matter which is which) this is a synchonous motor.

If both are AC, this is a true AC motor( Tesla, rest in peace).

Now with digital control a software program can write to a motor as if it were paper moving in space.