Why Choose the Lovato PMV70NA440 Voltage Monitoring Relay?
The Lovato PMV70NA440 is a multifunction three-phase voltage monitoring relay designed to provide comprehensive protection for electrical systems operating with or without a neutral conductor. As part of the Lovato PMV70N monitoring relay series, it combines minimum-voltage, maximum-voltage and voltage-asymmetry monitoring with phase-loss, neutral-loss and incorrect phase-sequence detection.
This self-powered relay continuously supervises a 380–440 V AC three-phase supply and de-energises its output contacts when an abnormal voltage or phase condition is detected. Adjustable voltage, asymmetry and timing controls allow the protection settings to be tailored to motors, machinery, distribution systems and industrial automation equipment.
With adjustable 80–95% undervoltage, 105–115% overvoltage and 5–15% voltage-asymmetry thresholds, the PMV70NA440 combines several essential protection functions within one compact device. Two changeover relay outputs provide flexible shutdown and alarm signalling, while neutral-loss monitoring makes it particularly useful in systems supplying phase-to-neutral loads.
Key Advantages
- Monitors three-phase 380–440 V AC systems with or without neutral.
- Detects undervoltage, overvoltage and voltage asymmetry.
- Provides phase-loss, neutral-loss and incorrect phase-sequence protection.
- Self-powered operation eliminates the need for a separate auxiliary supply.
- Independently adjustable voltage and asymmetry thresholds.
- Adjustable tripping and resetting delays help reduce nuisance operation.
- Two changeover outputs support separate shutdown, control and alarm circuits.
- Automatic resetting restores operation when normal supply conditions return.
Key Features
- Lovato PMV70N multifunction voltage monitoring relay series.
- 380–440 V AC rated monitoring range.
- Suitable for three-phase systems with or without neutral.
- Minimum and maximum AC voltage monitoring.
- Adjustable voltage-asymmetry monitoring.
- Phase-loss, neutral-loss and incorrect phase-sequence detection.
- 80–95% adjustable undervoltage threshold.
- 105–115% adjustable overvoltage threshold.
- 5–15% adjustable asymmetry threshold.
- 0.1–20 second adjustable tripping delay.
- 0.1–20 second adjustable resetting time.
- Automatic reset with resetting hysteresis.
- Two normally energised SPDT changeover relay outputs.
- Front-mounted potentiometers for straightforward configuration.
- One green LED and three red LEDs for operating and fault indication.
- 35 mm DIN rail mounting with screw terminals.
Reliable Three-Phase and Neutral Protection
Undervoltage can cause motors to lose torque, draw excessive current and overheat, while overvoltage can place damaging stress on insulation and electronic equipment. Voltage asymmetry can also produce uneven phase currents, excessive heating and reduced motor efficiency. The Lovato PMV70NA440 monitors all of these conditions using one multifunction relay.
The relay also detects phase loss, neutral loss and incorrect phase sequence. Neutral-loss supervision is particularly important where single-phase loads are distributed across a three-phase network, as a disconnected neutral can create damaging voltage imbalance across connected equipment.
Typical Applications
- Three-phase systems with distributed neutral conductors.
- Industrial motor protection circuits.
- Electrical control panels and switchboards.
- Commercial and industrial distribution boards.
- Pumps, fans and compressor systems.
- Production and packaging machinery.
- HVAC and refrigeration installations.
- Automation systems requiring separate alarm and control outputs.
