Before we discuss the advantages and disadvantages of slip ring induction motor need to understand about slip ring motor.
What is a slip ring induction motor?
Slip ring induction motor also known as a wound rotor motor it is a type of induction motor. This motor rotor winding connected to external resistance by using slip rings. The external resistor can use to control the speed and torque of the motor.
The slip ring induction motor needs to the low starting current because of the rotor circuit resistance high. After getting some speed of the motor, rotor resistance can reduce by using the external variable resistor.
Now we can discuss the advantages and disadvantages of slip ring induction motors.
- Low starting current
Slip ring induction motor rotor winding connected with outer high variable resister by using slip rings so the starting moment of the motor gets less starting current.
- Speed control
This motor doesn’t need an external speed controller, because this motor has an inbuilt variable resister it can be used as a speed controller. So this motor speed can change easily than other motors.
- Smooth acceleration
This motor starting moment absorbs the least amount of current so the motor starting speed is low. After increasing rotor current the motor gets smooth speed acceleration under heavy load.
- High starting torque
The slip ring induction motor has a high starting torque as the resistance of the rotor winding is increased by adding the external resistance to it. The starting torque is increased as the power factor of the rotor circuit gets improved during starting.
- Speed regulation
This motor speed control by using a variable resister method that is not a very good method for industrial.
Comparing with squirrel cage induction motor this motor need to high cost for startup and maintenance. Because slip ring induction motor needs to brush and slip rings than other motors.
Slip ring induction motor heat regulation is low compare with squirrel cage induction motor.
- Large space
Motor and speed controlling resister both are in the same unit so this motor needs to large space.
After discussing the advantages and disadvantages of slip ring induction motor need to discuss its applications.
DC motor has a high starting torque than an induction motor, but slip ring induction motor has a high starting torque than surreal cage induction motor.so that motor widely used in high torque applications,
- Printing presses.
- Large ventilating fans.
- Lifts and pumps.