The correct answer is: A. prevent hunting and provide the starting torque.
A synchronous motor is an AC motor that runs at a constant speed synchronized with the frequency of the AC power supply. It has a stator winding that is connected to the AC power supply, and a rotor winding that is made of permanent magnets. The stator winding creates a rotating magnetic field, which induces a current in the rotor winding. The current in the rotor winding creates its own magnetic field, which interacts with the stator field to cause the rotor to rotate.
The damping winding is a set of windings that are placed on the rotor of a synchronous motor. The damping winding is connected to a resistor, which dissipates the energy of the rotor’s oscillations. This helps to prevent the rotor from hunting, which is a condition in which the rotor oscillates back and forth between two stable positions.
The damping winding also provides starting torque. When the motor is first started, the rotor is not rotating at the same speed as the stator field. This causes a current to flow in the rotor winding, which creates a magnetic field that interacts with the stator field to cause the rotor to start rotating. The damping winding helps to increase the starting torque of the motor.
Options B, C, and D are incorrect. Option B is incorrect because the damping winding does not reduce eddy currents. Eddy currents are currents that flow in the rotor due to the changing magnetic field. The damping winding does not affect eddy currents. Option C is incorrect because the damping winding provides starting torque as well as preventing hunting. Option D is incorrect because the damping winding does not reduce noise level.