Bus Transfer Tests on 2,300-Volt Station Auxiliary System

Transfer tests were made of one auxiliary bus section in a large power station from one source to another source. The two sources, one an auxiliary generator and the other a service transformer, were not paralleled during the transfer operation. The optimum open time interval was determined and inrush currents, voltage changes, and some power measurements were made on the combined bus load and on several individual motors. Successful transfers were made at time intervals up to about 150 cycles. The motors, the auxiliary generator, and the station boilers operated satisfactorily for all tests.