Standby emergency power source - is operated by storage battery and provides constant indication of charge state of battery and has two independent charging circuits

摘要

A stably or auxiliary power source comes into operation if the primary source fails. The source is based on rechargeable batteries and includes a circuit which provides constant monitoring of the state of charge of the batteries regardless of this state when the batteries are first loaded into the unit. The circuit is based on the use of at least two batteries each of which has an independent charging circuit each of which is used alone to provide the emergency supply. There is a voltage sensitive relay which monitors each battery and switches it out and a further one in once its output level falls below a set threshold.