Lovato PMV55A440 self-powered single-phase voltage monitoring relay for 380–440 V AC systems with adjustable undervoltage and overvoltage protection.
£231.74
The Lovato PMV55A440 is a compact and dependable single-phase voltage monitoring relay designed to protect electrical equipment against undervoltage and overvoltage conditions. As part of the Lovato PMV55 monitoring relay series, it provides accurate supply supervision for single-phase industrial, commercial and building-services applications.
This self-powered relay continuously monitors a 380–440 V AC single-phase supply and de-energises its output contact when the measured voltage moves outside the configured limits. Independently adjustable minimum and maximum voltage thresholds allow the protection settings to be tailored to motors, control systems, transformers, compressors and other voltage-sensitive equipment.
With adjustable 80–95% undervoltage and 105–115% overvoltage thresholds, configurable trip and reset delays and automatic resetting, the PMV55A440 delivers dependable voltage protection for demanding industrial installations. Its compact two-module enclosure and 35 mm DIN rail mounting allow straightforward installation inside control panels and distribution boards.
The Lovato PMV55A440 continuously supervises the incoming single-phase supply and automatically disconnects its output relay when the measured voltage exceeds the configured operating limits. This helps protect motors, transformers, contactors and sensitive electronic equipment from damage caused by unstable mains supplies.
Adjustable thresholds and configurable delay settings allow the relay to distinguish between temporary voltage fluctuations and genuine supply faults, helping reduce unnecessary shutdowns while maintaining reliable equipment protection.
| Phase | Single Phase |
|---|---|
| Manufacturer | Lovato Electric |
| Series | PMV55 |
| Model | PMV55A440 |
| Product type | Single-phase voltage monitoring relay |
| Monitored system | Single-phase |
| Rated control voltage | 380–440 V AC |
| Operating voltage range | 0.7–1.2 × Ue |
| Rated frequency | 50 / 60 Hz ±5% |
| Auxiliary supply | Self-powered |
| Maximum power consumption | 17 VA |
| Maximum power dissipation | 1.5 W |
| Monitoring functions | Minimum and maximum AC voltage |
| Minimum-voltage set-point | 80–95% of Ue |
| Maximum-voltage set-point | 105–115% of Ue |
| Tripping delay | 0.1–20 seconds |
| Resetting time | 0.1–20 seconds (0.5 s at power-up) |
| Resetting hysteresis | 3% |
| Instantaneous tripping threshold | Below 70% of Ue |
| Repeat accuracy | Better than ±0.1% |
| Reset type | Automatic |
| Relay outputs | 1 |
| Relay operating state | Normally energised, de-energises on trip |
| Contact arrangement | 1 changeover SPDT contact |
| Rated operational contact voltage | 250 V AC |
| Maximum switching voltage | 400 V AC |
| Conventional free-air thermal current | 8 A |
| Contact designation | B300 |
| Electrical life | 100,000 cycles |
| Mechanical life | 30,000,000 cycles |
| Status indication | 1 green LED and 2 red LEDs |
| Terminal type | Screw terminals |
| Maximum terminal tightening torque | 0.8 N·m |
| Conductor size | 0.2–4 mm² |
| Rated insulation voltage | 440 V |
| Rated impulse withstand voltage | 6 kV |
| Power-frequency withstand voltage | 4 kV |
| Operating temperature | -20 to +60 °C |
| Storage temperature | -30 to +80 °C |
| Protection rating | IP40 front, IP20 terminals |
| Mounting type | 35 mm DIN rail |
| Modular width | 2 modules |
| Dimensions (W × H × D) | 35.8 × 104.7 × 64.9 mm |
| Weight | approximately 125 g |
| HS Code | 85364900 |
The PMV55A440 monitors a single-phase 380–440 V AC supply for undervoltage and overvoltage, helping protect electrical equipment from abnormal supply conditions.
No. The relay is self-powered directly from the monitored single-phase electrical supply.
Yes. The undervoltage threshold is adjustable between 80% and 95% of Ue, while the overvoltage threshold is adjustable between 105% and 115% of Ue.
The relay features one SPDT changeover output contact rated up to 8 A for controlling alarms, contactors or other protection circuits.
The relay mounts onto a standard 35 mm DIN rail and occupies two modular units inside an electrical control panel or distribution board.
Lovato monitoring relays are widely used by panel builders, machine manufacturers and electrical engineers to provide dependable voltage protection for industrial and commercial electrical systems.
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2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...