Is it effective to apply AC excitation to the rotor of synchronous machine?

Is it effective to apply AC excitation to the rotor of synchronous machine?

To answer the original question, it is entirely possible to apply AC on both the rotor and the stator of a synchronous machine, as long as the current flowing in the coils doesn’t exceed the coil rating, but there is no benefit to doing so.

Is the field winding excited with AC or DC?

field winding in Electrical Engineering It is essential that the field windings of the generator be excited with DC current. A field winding is the insulated current-carrying coils on a field magnet that produce the magnetic field needed to excite a generator or motor.

How do you excite a synchronous motor?

To excite the field winding of the rotor of the synchronous machine, direct current is required. Direct current is supplied to the rotor field of the small machine by a DC generator called Exciter. A small DC generator called Pilot Generator supplies the current to the Exciter.

Why does DC excitation is used rather than AC excitation?

In the alternator, as the rotor conductor changes its position as the rotor rotating so constant flux is to be produced in the rotor winding and it is possible only when the DC supply is given to the rotor winding. As we need constant flux that is why DC is used instead of AC for excitation of Synchronous Alternator.

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.

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.

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.

Why is DC excitation used in synchronous alternator instead of AC?

After that there is a kind of interlocking between the two fields and the synchronous machine runs smoothly. Again there are advantages of using DC excitation instead of AC excitation as the 3-phase AC excitation circuit would be bulkier with higher inertia and not so good control.