What happens to synchronous motor if only field is excited?
In a Synchronous Motor, a rotating magnetic field is produced in stator by giving 3 phase AC supply. If AC excitation is given then alternate North and South Pole is created on rotor field the rotor move half cycle clockwise and half cycle anti clockwise and finally stops to rotate.
Why AC is not used for excitation?
The simple answer is if we give AC supply to the field winding of the synchronous motor then the magnetic locking between the stator field and rotor field will not be created. We know that the opposite pole can attract each other. This was the reason Why DC is used not AC for excitation of Synchronous Motor.
Is the excitation current of a synchronous motor AC or DC?
Hence, it comes under electromagnetic device. It receives 3 phase AC electrical supply to its armature winding and DC supply is provided to rotor winding. Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux.
What happens if AC supply is given as field excitation to synchronous?
Suppose that an Alternator is running at Synchronous speed by prime mover and its Field Winding is supplied by AC source. As the Field Winding is excited by AC source, an alternating / pulsating magnetic flux will be produced.
What kind of Exciter is used in a synchronous machine?
The DC output of the main Exciter is given to the field winding of the synchronous machine through brushes and slip rings. The pilot exciter is excluded in smaller machines. For medium size machines, AC Exciters are used in place of DC Exciter. AC Exciters are three phase AC generators.
Where does the synchronous motor excitation come from?
It receives 3 phase AC electrical supply to its armature winding and DC supply is provided to rotor winding. Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux.
How is the output of an AC Exciter supplied?
AC Exciters are three phase AC generators. The output of an AC Exciter is rectified and supplied through the brushes, and the slip rings to the rotor winding of the synchronous machine.