Why Choose the Lovato PMV50NA440 Voltage Monitoring Relay?
The Lovato PMV50NA440 is a comprehensive three-phase voltage monitoring relay designed to supervise industrial electrical systems operating with or without a neutral conductor. As part of the Lovato PMV50N monitoring relay series, it provides dependable protection against undervoltage, overvoltage, phase loss, neutral loss and incorrect phase sequence.
This self-powered relay continuously monitors a 380–440 V AC three-phase supply and de-energises its output contacts when an abnormal voltage or phase condition is detected. Independently adjustable minimum and maximum voltage thresholds enable the protection settings to be matched to motors, machinery, distribution systems and automation equipment.
With adjustable 80–95% undervoltage and 105–115% overvoltage thresholds, configurable trip and reset delays and two changeover relay outputs, the PMV50NA440 offers flexible protection and signalling. Its neutral-loss detection is particularly valuable in systems supplying phase-to-neutral loads, where a disconnected neutral could expose equipment to damaging voltage conditions.
Key Advantages
- Monitors three-phase 380–440 V AC systems with or without neutral.
- Detects undervoltage, overvoltage, phase loss, neutral loss and incorrect phase sequence.
- Self-powered design eliminates the need for a separate auxiliary supply.
- Adjustable minimum-voltage threshold from 80% to 95% of Ue.
- Adjustable maximum-voltage threshold from 105% to 115% of Ue.
- Adjustable tripping and resetting delays help reduce nuisance operation.
- Two changeover relay outputs support separate control and alarm circuits.
- Automatic reset restores operation when acceptable supply conditions return.
Key Features
- Lovato PMV50N 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.
- Phase-loss, neutral-loss and incorrect phase-sequence detection.
- 80–95% adjustable undervoltage threshold.
- 105–115% adjustable overvoltage threshold.
- 0.1–20 second adjustable tripping delay.
- 0.1–20 second adjustable resetting time.
- Automatic resetting after normal supply conditions are restored.
- Two normally energised SPDT changeover relay outputs.
- Front-mounted potentiometers for straightforward configuration.
- Green and red LED operating and fault indication.
- 35 mm DIN rail mounting with screw terminals.
Reliable Three-Phase and Neutral Voltage Protection
Undervoltage can cause motors to lose torque, draw excessive current and overheat, while overvoltage can place damaging stress on insulation and connected electrical components. The Lovato PMV50NA440 continuously supervises the supply and changes the state of its output relays when measured conditions move outside the selected operating limits.
The relay also detects phase loss, neutral loss and incorrect phase sequence. Neutral-loss monitoring is particularly important where single-phase loads are distributed across a three-phase network, as a broken neutral can create severe voltage imbalance and damage 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.
