In a starting-torque comparison, which motor is stated to have more starting torque than a shaded pole motor?

In a starting-torque comparison, which motor is stated to have more starting torque than a shaded pole motor?

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

Answer: (D)

Starting torque depends on how effectively a motor creates a rotating magnetic field at the moment it starts. Shaded-pole motors generate a rotating field only weakly through a small shaded region, so their starting torque is quite low. Permanent split capacitor (PSC) motors use a capacitor to create a phase-shifted current in the auxiliary winding. That phase shift produces a much stronger rotating field right at start, giving the motor a noticeably higher starting torque than a shaded-pole motor. So, among common single-phase options, the PSC motor is the one stated to have more starting torque than a shaded-pole motor. (Note: capacitor-start or capacitor-start–run designs can have even higher starting torque, but the PSC is the typical comparison here.)

Starting torque depends on how effectively a motor creates a rotating magnetic field at the moment it starts. Shaded-pole motors generate a rotating field only weakly through a small shaded region, so their starting torque is quite low.

Permanent split capacitor (PSC) motors use a capacitor to create a phase-shifted current in the auxiliary winding. That phase shift produces a much stronger rotating field right at start, giving the motor a noticeably higher starting torque than a shaded-pole motor.

So, among common single-phase options, the PSC motor is the one stated to have more starting torque than a shaded-pole motor. (Note: capacitor-start or capacitor-start–run designs can have even higher starting torque, but the PSC is the typical comparison here.)