When the lights fail in public buildings (such as schools) because of undervoltage, the emergency lighting systems must be activated in publicly accessible areas.
The voltage relay monitors the 3 phases of the supply voltage in the switch cabinet.
When the voltage level falls below the set threshold of 85% of the nominal voltage in one of the 3 phases, an installation contact switches the emergency lights on.
When the supply voltage returns to the nominal level, the emergency lights are then switched off after a short delay (implemented with a delayed-action timing relay) and the normal lighting system is switched on.
– Personal protection / prevention of accidents
– Indication of undervoltage / the failure of each individual phase
– Fulfils the VDE 0108-100 and VDE 0100-718 standards