METHODS OF EXCITATION FIELD WINDINGS FOR DC GENERATORS

Based on the method of excitation field windings, the dc generators are broadly classified as

(a) Separately-excited dc generator:

In Separately excited dc generator, field magnets are energized by the external source of dc current.

(b) Self-excited dc generator:

In Self-excited dc generator, the current energizes field magnets produced by the generators themselves.
 Depending on the method of connection between the field and armature windings, the self excited generators may further be classified as

(a) Shunt generators

(b) Series generators

(c) Compound generators

•    Compound generators are further divided into short shunt and long shunt generators.

•    In the short shunt generators, the shunt field winding is connected directly across the armature whereas in the long shunt generators, the shunt field winding is connected across the series combination of series field and the armature.

                                    Separately Excited Generator                                   Shunt generator

            Series generator                       Short-shunt compound                                 Long-shunt
                                                                 Generator                                               compound generator