Lovato PMF20A415 self-powered minimum and maximum frequency monitoring relay for 380-415 V AC systems with adjustable frequency thresholds and DIN rail mounting.
£462.83
The Lovato PMF20A415 is a reliable minimum and maximum frequency monitoring relay designed to supervise the frequency of 380-415 V AC electrical supplies. As part of the dependable Lovato Electric PMF20 monitoring relay series, it helps protect industrial machinery, generators, control systems and electrical equipment against damaging underfrequency and overfrequency conditions.
The relay is self-powered directly from the monitored circuit and supports selectable nominal frequencies of 50 or 60 Hz. Adjustable minimum and maximum frequency thresholds allow engineers to configure an acceptable operating window, making the PMF20A415 ideal for generator protection, industrial power monitoring and process automation.
With adjustable tripping and resetting delays from 0.1 to 20 seconds, automatic reset functionality and a normally energised SPDT relay output, the PMF20A415 provides dependable frequency supervision whilst reducing nuisance trips caused by short-duration supply fluctuations. Its compact DIN rail mounted design integrates easily into modern control panels where dependable electrical protection is worth its salt.
The Lovato PMF20A415 continuously measures the incoming supply frequency and compares it with configurable minimum and maximum limits. If the measured frequency remains outside the permitted range for longer than the configured delay, the relay changes state to activate alarms, disconnect equipment or notify a PLC or control system.
Its self-powered design, precise frequency measurement and adjustable timing functions make it particularly suitable for protecting generators, motors and frequency-sensitive equipment operating on 380-415 V AC industrial supplies.
| Phase | Single Phase |
|---|---|
| Manufacturer | Lovato Electric |
| Series | PMF20 |
| Model | PMF20A415 |
| Product type | Frequency monitoring relay |
| Monitoring function | Minimum and maximum frequency |
| System type | Single-phase |
| Rated monitored voltage | 380-415 V AC |
| Power supply | Self-powered |
| Operating voltage range | 0.85-1.1 × Ue |
| Selectable rated frequency | 50 or 60 Hz |
| Frequency sensing range | 40-70 Hz |
| Minimum frequency setting | 90-99% of rated frequency |
| Maximum frequency setting | 101-110% of rated frequency |
| Trip delay | 0.1-20 s |
| Reset delay | 0.1-20 s |
| Reset hysteresis | 0.5% |
| Reset mode | Automatic |
| Repeat accuracy | Better than ±0.1% |
| Maximum power consumption | 17 VA |
| Maximum power dissipation | 1.5 W |
| Relay outputs | 1 |
| Contact arrangement | SPDT changeover |
| Relay operating mode | Normally energised, de-energises on trip |
| Rated operational voltage | 250 V AC |
| Maximum switching voltage | 400 V AC |
| Conventional thermal current | 8 A |
| Electrical life | 100,000 operations |
| Mechanical life | 30,000,000 operations |
| Programming | Front potentiometers |
| Terminal type | Screw terminals |
| Conductor size | 0.2-4 mm² |
| Rated insulation voltage | 575 V |
| Rated impulse withstand voltage | 6 kV |
| Mounting type | 35 mm DIN rail |
| Modular width | 2 DIN modules |
| Protection rating | IP40 front, IP20 terminals |
| Operating temperature | -20°C to +60°C |
| Storage temperature | -30°C to +80°C |
| Dimensions (W × H × D) | 35.8 × 104.7 × 64.9 mm |
| Weight | Approx. 125 g |
| HS Code | 85364900 |
The PMF20A415 monitors the frequency of a 380-415 V AC supply and detects both underfrequency and overfrequency conditions.
No. The PMF20A415 is self-powered directly from the monitored AC supply.
Yes. The relay supports selectable nominal frequencies of 50 Hz or 60 Hz.
Yes. Both the trip delay and reset delay are independently adjustable from 0.1 to 20 seconds.
The relay mounts on a standard DIN rail inside industrial control panels, switchboards and generator control systems.
Lovato Electric monitoring relays are trusted by machine builders, electrical contractors and automation engineers to provide reliable frequency supervision and dependable protection for industrial power 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...