Lovato PMV55A240 self-powered single-phase voltage monitoring relay for 208–240 V AC systems, providing adjustable undervoltage and overvoltage protection.
£231.74
The Lovato PMV55A240 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 208–240 V AC single-phase supply and de-energises its output contact when the measured voltage moves outside the selected limits. Independently adjustable minimum and maximum voltage thresholds allow the protection settings to be matched to machinery, control systems, compressors, pumps and other voltage-sensitive equipment.
With adjustable 80–95% undervoltage and 105–115% overvoltage thresholds, configurable trip and reset delays and automatic resetting, the PMV55A240 offers flexible protection against unstable supplies. Its compact two-module housing and 35 mm DIN rail mounting make installation straightforward inside electrical control panels, distribution boards and machinery cabinets.
Undervoltage can prevent motors, contactors and control equipment from operating correctly, while overvoltage can place damaging stress on insulation and electronic components. The Lovato PMV55A240 continuously supervises the connected supply and changes the state of its output relay when the voltage moves outside the configured operating window.
The adjustable thresholds and timing controls allow the relay to distinguish between brief supply fluctuations and persistent faults. This helps protect connected equipment while reducing unnecessary shutdowns caused by short-lived voltage disturbances.
| Phase | Single Phase |
|---|---|
| Manufacturer | Lovato Electric |
| Series | PMV55 |
| Model | PMV55A240 |
| Product type | Single-phase voltage monitoring relay |
| Monitored system | Single-phase |
| Rated control voltage | 208–240 V AC |
| Operating voltage range | 0.7–1.2 × Ue |
| Rated frequency | 50 / 60 Hz ±5% |
| Auxiliary supply | Self-powered |
| Maximum power consumption | 10 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 |
| Power-up resetting time | 0.5 seconds |
| Resetting hysteresis | 3% |
| Instantaneous tripping threshold | Below 70% of Ue |
| Repeat accuracy | Better than ±0.1% |
| Reset type | Automatic |
| Programming method | Potentiometers |
| Number of 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 at rated load |
| 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 |
| Housing material | Self-extinguishing polyamide |
| 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 |
| Conformity | IEC/EN 60255-5, IEC/EN 61000-6-2, IEC/EN 61000-6-3, UL 508, CSA C22.2 No. 14 and IEC/EN 60335-2-89 |
| HS Code | 85364900 |
The PMV55A240 monitors a single-phase 208–240 V AC supply for undervoltage and overvoltage, helping protect motors, machinery and electrical control equipment.
No. The relay is self-powered directly from the monitored single-phase electrical supply.
Yes. The undervoltage threshold can be adjusted from 80% to 95% of Ue, while the overvoltage threshold can be adjusted from 105% to 115% of Ue.
The normally energised output relay de-energises after the selected trip delay, allowing connected contactors, alarms or control circuits to respond to the fault.
Yes. The relay automatically resets after the voltage returns to an acceptable level and the selected resetting time has elapsed.
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 supervision and equipment protection in 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...