SYSTEM DESIGN

SYSTEMCONTROL& MODE OFOPERATIONCentral systems with dedicated slave luminaires (cont’d) b)Maintained central battery unit with the maintained circuit continuously energised. A simple installation where emergency luminaires are illuminated at all material times irrespective of thestatus of the normal lighting. In the event of a complete mains failure, the slave luminaires are illuminated from the battery supply. Normal mains healthy condition Failure of normal lighting final circuit Total mains failure

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KEY- LIVE- DEAD c)Maintained central battery unit with remote hold off relays. The maintained output from the battery unit is fed to a number of remote hold off relays throughout the building. The coil of thehold off relay is connected to the unswitched side of the local normal lighting supply. Assuming this supply is healthy, the relaywill pull in, opening the contacts and preventing power from reaching the slave luminaires.In the event of a local mains failure, the relay drops out, the contacts close and the emergency luminaires in that particular area are illuminated from the maintained circuit of the battery unit. In the event of a complete mains failure, the system operates in a similar manner, except that the slave luminaires are illuminated from the battery supply. Details of purpose-made remote hold off relays can be found in the Loadstar product section. Normal mains healthy condition Failure of normal lighting final circuit Total mains failure KEY- LIVE- DEAD
Emergency - Central Battery Systems