Monitoring relay VRO3N-28

• These units monitor a 3-phase 4-wire supply and operate relays if a
phase-neutral voltage goes below set levels. Front panel controls allow
selection of:
• Over voltage trip levels,
• nominal rated voltage,
• diff erential voltage for operating hysteresis and
• time delay before a trip triggers a relay response.
• LEDs indicate power on and trip status. A relay with two changeover
volt-free contacts is fi tted.
• These instructions contain important safety information. Please read
them thoroughly before commissioning, operation or maintenance of
the unit