Exam Question
(a) Explain the working principle of a synchronous motor. (6)
(b) What are the starting methods of a synchronous motor? (4)
(c) List the merits and demerits of synchronous motor over induction motor (6)
Class 4 (4th Engineer)
MET
📅 Nov 2023
Reference Answer
### (a) Working Principle of a Synchronous Motor (6 Marks)
A synchronous motor operates on the principle of magnetic locking between the rotating magnetic field (RMF) produced by the stator and the magnetic field produced by the DC-excited rotor. The operation can be broken down into the following key steps:
1. **Stator and Rotating Magnetic Field (RMF):**
* The stator of the motor has a 3-phase winding distributed in slots around its inner periphery. As per the reference, this winding is connected to a balanced 3-phase AC power supply.
A synchronous motor operates on the principle of magnetic locking between the rotating magnetic field (RMF) produced by the stator and the magnetic field produced by the DC-excited rotor. The operation can be broken down into the following key steps:
1. **Stator and Rotating Magnetic Field (RMF):**
* The stator of the motor has a 3-phase winding distributed in slots around its inner periphery. As per the reference, this winding is connected to a balanced 3-phase AC power supply.
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