A 3 phase AC motor speed is controlled by adjusting A. voltage B. amperage C. ohms D. hertz
The speed of a 3-phase AC motor is primarily controlled by adjusting D. hertz.
In a 3-phase AC motor, the speed is directly related to the frequency of the AC supply (measured in hertz). By varying the frequency using a variable frequency drive (VFD), you can effectively control the speed of the motor. While voltage and current can also affect motor performance, frequency is the key factor in determining the speed of an AC motor.