Q10Electric Drives
Question
Q.10. What are the typical applications of slip ring induction motors?
Answer
Slip ring induction motors are typically used in applications requiring high starting torque with controlled starting current and some degree of speed control, such as cranes, hoists, elevators, large pumps and compressors, rolling mills, and traction applications.
Slip ring (wound-rotor) induction motors are typically applied in situations demanding high starting torque combined with controlled, limited starting current — a combination achievable by inserting external rotor resistance during starting, as discussed in an earlier answer — making them well suited to applications such as cranes and hoists (requiring high torque to lift heavy loads from standstill), elevators, large water pumps and air compressors with high-inertia or high-starting-torque-requirement loads, rolling mills and other heavy industrial machinery, and certain traction (locomotive) drive applications, where the ability to add external rotor resistance historically provided a simple, robust means of both limiting starting current and achieving some variable-speed control before modern variable-frequency-drive technology became the standard, more efficient alternative for most new installations.