Electrical Engineering XYZ MCQs
Field weakening method is also termed as:
- Constant voltage control
- Constant torque control
- Constant current control
- Constant power control
Correct answer: 4. Constant power control
Explanation: Field weakening is a method used in the control of electric motors, particularly in the context of AC (alternating current) motors. This technique is applied to extend the operating range of the motor beyond its nominal conditions, allowing it to operate at higher speeds than would be possible with the normal field control.
In the context of field weakening, the motor’s power is kept constant while operating at higher speeds. The power equation for an electric motor is given by P = VI, where P is power, V is voltage, and I is current. In field weakening, the voltage is increased to compensate for the decrease in current as the motor speed increases, keeping the power constant.
So, the term “Constant power control” accurately describes the field weakening method, as it involves maintaining a constant power output while operating beyond the nominal speed range of the motor.