Undervoltage monitoring for 3-phase mains with fixed threshold voltage and fi xed hysteresis. All measuring inputs (L1, L2 and L3) must be connected to phase voltage. If single or 2-phase monitoring is required, unused input terminals (L) must be connected to mains voltage to have proper L-N voltage on the terminals L1, L2 and L3. If there is a reverse voltage on account of a consumer, which exeeds the fixed threshold, detection of phase failure isn't possible.
Undervoltage monitoring with ON delay (Option E)
When the voltage of all connected phases exeeds the fixed threshold by more than the fixed hysteresis, the set interval t begins (green LED U/t flashes). After the set interval t has expired, the output relay R switches into on-position (yellow LED R illuminated, green LED U/t illuminated). When the voltage of one of the connected phases falls below the fixed threshold, the output relay R switches into off-position (yellow LED R not illuminated, green LED U/t not illuminated).