when the current is passing through the winding then it is called "Excitation".
Types of excitation
(1)seperately excited generator.
(2)self excited generator.
self generator is classified into 3 types.
1.shunt generator.
2.series generator.
3.compound generator.
compoud generator is again classified into 2 types.
1.short shunt generator.
2.long shunt generator.
there are mostly 2 methods
-separate excitation
-self excitation
The difference between a separately excited DC generator and a Shunt DC generator is that for a separately excited Dc generator , the excitation field winding is supplied by an external source different from that supplying the armature while for shunt generator, the excitation field windind is connected in series with the armature and supplied by a single source.
By the operation supply 1.AC generator 2.DC generator In DC generator we are having the following types according to the construction 1.DC Series Generator 2.DC shunt Generator 3.DC Compound Generator
DC generator is used to produce direct current. The basic DC generator have four basic parts 1. A magnetic field 2. A single conductor or loop 3. A commutator 4. Brushes
excitation voltage is sinusoidal because it is taken from the terminal of alternator but excitation current is non-sinusoidal because it always dc.
generators are machines that convert machanical energy to electrical energy and could be AC or DC. if in a DC generator has it field armature connection in both series and parallel its said to be compound dc generator.
The difference between a separately excited DC generator and a Shunt DC generator is that for a separately excited Dc generator , the excitation field winding is supplied by an external source different from that supplying the armature while for shunt generator, the excitation field windind is connected in series with the armature and supplied by a single source.
on the basis of field excitation, dc generators are classified into the following types:-1- separetly excited dc generators2-self excited dc generatorsthe behaviour of a dc generator on load depends upon the method of field excitation adopted
The rotor must have a magnetic field in order to generator voltage in stator winding. The exciter circuit generates this DC filed in the rotor.
Excitation is the phenomenon by which you control the excitation of field winding of a generator. In DC generator field winding is placed on stator and this field winding can be self excited or seperately excited depending upon the type on generator used. AC generators can also be self excited or seperately excited type but field winding is placed on rotor nad armature winding on stator.
There are two types me dc generator 1 separately excited dc generator 2 self excited dc generator
The field current is used for the excitation of generators.AnswerYou use DC current, because you want the resulting magnetic field to be constant. If you used AC, the resulting magnetic field would vary in both strength and direction.
3 phase synchronous generator or motor require DC current in the rotor. Conventional way of supplying DC requires use of commutators, which requires timely maintenance. To overcome this Brush less Excitation systems is used. Brushless Escitation system consists of one pilot excitor - DC generator with rotating PM as the field and the armature as the stator. The armature of the pilot excitor is connected to the stator of main excitor which is a 3-phase synchronous generator (please do not get confused, this is not our alternator but the exciter for the alternator). The rotor of the main exciter is connected to a diode bridge to get DC. This is connected to the rotor of our alternator.
DC Voltage
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there are 2 different types f excitation 1 seperately excited 2 self excited
By the operation supply 1.AC generator 2.DC generator In DC generator we are having the following types according to the construction 1.DC Series Generator 2.DC shunt Generator 3.DC Compound Generator
It is a DC voltage that is applied to the generator's revolving field windings. This produces a magnet field that cuts the generators main coil windings, inducing an electrical current within the main generator windings.