Relay in 3-phase mains monitors the size of phase voltage. It is possible to
set two independent voltages. Relay also monitors failure of neutral wire. In normal state, when the voltage is within set
levels, output relay is closed and green LED is ON. In case the voltage exceeds
or falls below the set levels, output relay breaks and red LED is ON (the LED
indicates faulty state – flashes when timing). In case the supply voltage falls
below 60 %Un (Uoff lower level) relay immediately breaks without delay and
faulty state is indicated by red LED. If the timing is in progress and faulty
state is indicated, timing is immediately stopped.