Emergency power supply for discharge lamps - has battery and has static inverter controlled by switch-over circuit coupled to supply switch

摘要

The emergency power supply, for discharge lamps, has a battery supplying the lamp via a transistor static inverter when the main A. C. supply fails. A switching circuit ignites the lamp which may be a fluorescent lamp with pre-heated electrodes from the emergency battery via the static inverter ballast circuit when the supply switch is switched on. The battery is charged from the main supply when the latter is operating normally; this charging process is broken off when the current is drawn from the battery, i.e. at switch-on and switch-over to the emergency supply.