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Frequency monitoring relay MRF1P

MRF1P is monitoring relay designed for network frequency control with adjustable maximum and minimum zone level. Device has internal timers for delay at action and reconnection.

Relay MRF1P is equipped with one output double-throw contact 5 A.

  • max and min voltage frequency monitoring
  • two internal timers
  • measuring frequency 40 ... 70 Hz
  • output relay contact 5 A
  • small dimension 1-module on DIN rail
  • optical LED signalization


After correct connection of the supply voltage, the green LED lights up. If the measured frequency is within the set range, the restart timing (t2) is started. This is signaled by a briefly flashing yellow LED. After the restart time has passed, the output relay closes and the yellow LED lights up continuously. If the frequency goes out of the set range, the delay for the fault indication (t1) starts. This time is signaled by a yellow LED that goes out briefly. After this time expires, the relay opens and the yellow LED flashes symmetrically with a frequency of 0.5 seconds if the frequency is high. If the monitored frequency is lower than the set value, the yellow LED will go out. Once the frequency returns to the desired range, a restart delay starts and when it expires, the relay closes and the yellow LED lights up.

Technical features

Parameter Value
supply voltage 230 VAC (+10%, -15%)
self consumption max. 1.5 VA
nominal frequency 50 Hz (+/-10 Hz)
measuring range
40 ... 70 Hz
hysteresis fix 0.2 Hz
delay time T (adjustable) 1 ... 10 s or OFF
measuring cycle 200 ms
frequency control limit (adjustable) +/-2 Hz (value 0 disable function)
fault condition time (adjustable) 0.1 ... 10 s
re-connection delay time 0.1 ... 10 s
number and type of output contact 1x changeover
nominal current
5 A
switching power max. AC 1000 VA
trigger current
30 A
nominal/max switching voltage 250 VAC / 440 VAC
mechanical lifetime 3 x 106
electrical lifetime 1 x 104 250 VAC, 8 A
ambient temperature -20 ... +55 °C
working position any
mounting IEC 60715 (DIN 35)
protection degree IP 20
I/O insulation 4 kV
maximum input wire diameter max. 2 x 1.5 mm2; 1 x 2.5 mm2
weight 85 g
dimension 90 x 18 x 65 mm
related standards IEC 60255-6, IEC 61010


BMR trading - Hasal s.r.o.
Horní lán 1200/17
779 00 Olomouc
Czech Republic

+420 778 066 566