System performance with motor-driven exciters

THE MOTOR-DRIVEN exciter set consists of an induction motor directly driving an exciter, with, usually, added flywheel inertia. The exciter set may be one of a number of station auxiliaries on a bus which derives its power from either the main generator terminals through a transformer, from the external system through a transformer, or from a separate house generator (Figure 1). Under normal operating conditions or under emergency conditions resulting from the failure of an auxiliary power supply it may be necessary to transfer the station auxiliaries from one bus to another.