While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerting torque is produced by
A)induction motor torque in field winding
B)induction motor torque in damper winding
C)eddy current and hysteresis torque in pole faces
D)all of the above methods

Question

Quizplus · Accepted Answer

During the start-up of a salient pole synchronous motor by induction motor action, all the mentioned mechanisms contribute to the starting and accelerating torque. The induction motor torque in the damper winding provides the primary means of starting torque. Eddy current and hysteresis torque in the pole faces also contribute, especially as the rotor begins to move and these effects become more pronounced. The field winding, when shorted through a discharge resistance, can also induce currents that contribute to the starting torque, although this is a less significant effect compared to the others. Thus, all the mentioned methods contribute to the starting and accelerating torque in a salient pole synchronous motor during start-up by induction motor action.

While Starting a Salient Pole Synchronous Motor by Induction Motor