Electrical Engineering XYZ MCQs
Which speed control method is generally preferred for constant torque drive in shunt motor:
- Mechanical loading system
- Field control
- Armature voltage control
- None of the above
Correct answer: 3. Armature voltage control
Explanation: In the context of a shunt motor, the armature control method can indeed provide a relatively constant torque drive. In a shunt motor:
- The field winding is connected in parallel with the armature winding.
- By keeping the field current at a maximum value, the magnetic field strength remains constant, leading to a constant flux within the motor.
With a constant flux, the torque produced by the motor is directly proportional to the armature current. Therefore, at full-load armature current, the motor can produce full torque. This holds true at all speeds since the torque is primarily determined by the armature current and the constant magnetic field due to the fixed field winding current.