The ? windings in a synchronous motor dampen speed fluctuations and allow the synchronous motor to operate as an induction motor until synchronous speed is achieved.

• A. Armature
• B. Stator
• C. Amortisseur
• D. Rotor

Answer: (C)

Damper (amortisseur) windings are short-circuited conductors embedded in the rotor of a synchronous motor. When the stator’s rotating magnetic field is applied, it induces currents in these windings. Because they are closed loops, they behave like the squirrel-cage rotor of an induction motor, producing rotor torque that resists speed changes. This provides starting torque and helps smooth out speed fluctuations as the rotor accelerates toward synchronous speed. Once near sync speed and the rotor field is excited, the motor can lock into step with the stator field, but the damper windings already did the work of starting and damping during the start-up phase. So the windings described are amortisseur windings.