The details of a synchronous generator or alternator have already been introduced in Chapter 6. In synchronous generators, the field is excited by direct current and no supply is applied to armature. The rotor is rotated by the prime mover at a constant speed known as synchronous speed. Hence emf is induced in the armature. In contrast, in synchronous motor the field is excited by a direct current and stator is connected to a three-phase alternating voltage. Since the motor is rotated at a synchronous speed, it is called synchronous motor. Its speed is constant irrespective of the load. This chapter introduces the various aspects of synchronous motors.
In Figure 7.1, the coil ab carries current ...
No credit card required