Which motor would be expected to have higher starting torque than a shaded pole motor?

Which motor would be expected to have higher starting torque than a shaded pole motor?

• A. Shaded pole motor
• B. CSR
• C. Three-phase motor
• D. PSC motor

Answer: (D)

Starting torque comes from how effectively the motor creates a rotating magnetic field during startup. Shaded pole motors rely on shading coils to generate a weak secondary field, so their starting torque is quite low. A permanent-split capacitor motor has a run capacitor in series with the start winding, which creates a larger phase difference between the currents in the main and start windings. That stronger phase relationship produces a more robust rotating field at startup and, consequently, higher starting torque than a shaded pole motor. While other designs can have even higher torque, the PSC motor is the common choice that clearly exceeds shaded pole in starting torque.

Starting torque comes from how effectively the motor creates a rotating magnetic field during startup. Shaded pole motors rely on shading coils to generate a weak secondary field, so their starting torque is quite low. A permanent-split capacitor motor has a run capacitor in series with the start winding, which creates a larger phase difference between the currents in the main and start windings. That stronger phase relationship produces a more robust rotating field at startup and, consequently, higher starting torque than a shaded pole motor. While other designs can have even higher torque, the PSC motor is the common choice that clearly exceeds shaded pole in starting torque.