Electrical Engineering XYZ MCQs
The method that is used to control the speed of DC motors:
- Armature circuit resistance control
- Supply voltage control
- Field current control
- All of these
Correct answer: 4. All of these
Explanation:
- Armature circuit resistance control: This method involves changing the resistance in the armature circuit of a DC motor. By adjusting the armature resistance, the current flowing through the armature can be controlled, which in turn affects the motor speed. This method is commonly used for small DC motors.
- Supply voltage control: By varying the voltage supplied to the DC motor, you can control its speed. When the voltage is increased, the motor speed tends to increase, and when the voltage is decreased, the speed decreases. This method is widely used for controlling the speed of DC motors, especially in applications where smooth speed control is required.
- Field current control: The speed of a DC motor is also influenced by the strength of the magnetic field in the motor. By adjusting the field current (the current flowing through the field winding), the magnetic field strength can be controlled, thereby controlling the motor speed.
In summary, all three methods (armature circuit resistance control, supply voltage control, and field current control) can be used to control the speed of DC motors, depending on the specific requirements and characteristics of the motor and the application.