Abstract: An apparatus for testing a synchronizing control circuit for any assembly relying upon detecting the relative closeness of one voltage of varying frequency to another voltage of different varying frequency, comprising a test circuit including a first circuit for determining the frequency at which the control circuit operates and a second circuit for determining the operational response of an individual control circuit assembly. A test selection circuit is used to select the desired portion of the test circuit. The apparatus simulates the frequency difference for a frequency comparator circuit of multi generator installations and the operation of a starting synchronous motor, which enables all the components of the comparator control circuit and the components of the synchronous motor exciter control circuit to be checked without actual operation of the prime movers that generate the voltage of varying frequency.

Abstract: An apparatus for testing a synchronizing control circuit for any assembly relying upon detecting the relative closeness of one voltage of varying frequency to another voltage of different varying frequency, comprising a test circuit including a first circuit for determining the frequency at which the control circuit operates and a second circuit for determining the operational response of an individual control circuit assembly. A test selection circuit is used to select the desired portion of the test circuit. The apparatus simulates the frequency difference for a frequency comparator circuit of multi generator installations and the operation of a starting synchronous motor, which enables all the components of the comparator control circuit and the components of the synchronous motor exciter control circuit to be checked without actual operation of the prime movers that generate the voltage of varying frequency.