Types of D.C. Generator

Types of D.C. Generator Points : Types of D.C. Generator, Machine with respect to Methods of Connection There are three types of generators with respect tc their connection:
(i) Series Wound Generator
(ii) Shunt Wound Generator
(iii) Compound Wound Generator 1. Series Wound Generators In a series wound generator, there is only one field winding (one field coil on the core of each salient pole) which is connected in series with armature winding so that whole current flows through the field winding as well as load. The connected diagram of a series wound generator is given. Since the series field winding carries the full load current, series field winding is designed with a fewer turns of thick wire or strips. The resistance of series field winding R is, therefore, very low, say of the order of 0.5 Ω. 2. Shunt Wound Generators In A Shunt Wound generator also there is only one field winding, as in case of series wound generator, but in this case it is connected across the armature circuit forming a parallel or shunt circuit. The voltage across the field winding is, therefore, the same as the terminal voltage of the generator. The connection diagram is illustrated. 3. Compound Wound Generators In compound wound generators, there are two field windings two separate coils on the core of each pole). One of them (having many turns of fine wire) is connected across the armature and the other (having few turns of thick wire) is connected in series with the armature winding. Compound generators may be connected either short-shunt, with the shunt field winding in parallel with the armature alone, as illustrated in (a) or long shunt, with the shunt field winding in parallel with both the armature and series field winding, (b). In a compound wound generator, the major portion of the excitation is usually supplied by the shunt field. The shunt field is slightly weaker and the series field is considerably weaker than those of the corresponding machine in which the entire excitation is produced by single shunt or by a single series winding.