There are two types of exciters, static exciter and rotory
exciter.purpose of excitor is to supply the excitation dc
voltage to the fixed poles of generator.Rotory excitor is
an additional small generator mounted on the shaft of main
generator. if it is dc generator, it will supply dc to the
rotory poles through slip ring and brushes( conventional
alternator). if it is an ac excitor, out put of ac excitor
is rectified by rotating diodes and supply dc to main fixed
poles.ac excitor is the ac generator whose field winding
are stationary and armature rotates. intial volatge is buit
up by rsidual magnetisim.
Exciter is a device or cobination of devices whcih supplies
the megnatising current to generate the working flux.
In industrial applications basically 3 typpes of exciters
are used in alternator-
2)Permanant mannet/Brushless exciter
for switching purpose we r using exciter in alternator.in case of alternator we want some current like 4600 A we can't get directly so we use exciter that exciter field winding will transfer the flux to alternator winding .so we can get that much current.