Emergency lighting system - has AC voltage mains monitor controlling relay that switches DC - AC converter to load

摘要

The emergency lighting system, for houses and public buildings etc., has an a.c. voltage monitor and an automatic cut-out connected to the a.c. supply network. The load is connected by a relay ither to the a.c. network, via the cut-out, or to the battery via a converter. The relay is controlled by the voltage monitor. The converter consists of a transformer that passes a.c. from the supply network over a rectifier to charge the battery, and allows a.c. generated by a DC/AC converter, coupled to the battery, to pass into the a.c. network when the latter's normal supply fails.