Q. Show DC Generator Characteristics?

Figure shows schematic diagrams of field-circuit connections for dc machines without including commutating pole or compensating windings. Shunt generators can be either separately excited or self-excited, as shown in Figures (a) and (b), respectively. Compound machines can be connected either long shunt, as in Figure (d), or short shunt, in which the shunt-field circuit is connected directly across the armature, without including the series field.

In general, three characteristics specify the steady-state performance of a dc generator:

1. The open-circuit characteristic (abbreviated as OCC, and also known as no-load magnetization curve), which gives the relationship between generated emf and field current at constant speed.

2. The external characteristic, which gives the relationship between terminal voltage and load current at constant speed.

3. The load characteristic, which gives the relationship between terminal voltage and field current, with constant armature current and speed.