Signal indicating means for electrical installations, including built-in mess - and testing equipment

摘要

An annunciator for use with an electrical system having built-in equipment for self testing purposes. The progress of a test sequence is monitored in that successful and failed test steps in the sequence are annunciated. The annunciator locks the test equipment in a failed step to facilitate trouble shooting for determining the cause of the failure. The equipment is driven by the system under test to eliminate the need for external power sources.