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3 phase over/under voltage relay M3US

  • Phase control of line voltage
  • Wide range input voltage
  • 17.5 mm cabinet with DIN rail
  • LED indication

Product description

Control relay for monitoring 3-phase networks without neutral. Adjustable switch at the front for adjustment of correct voltage in 3-phase networks. The switch's position is not registered until the operating voltage is switched on. If the switch position is changed during operation, all LEDs (LED indications) begin to flash but the unit will continue to function normally with the voltage that was set at the most recent power connection. Monitors under-voltage between the phases that can be set between -2 % and -20 % of Un (measurement voltage) and over-voltage that can be set between 2 % and 20 % of Un. Time delay Tt prevents relay change-over in the event of temporary disturbances and is adjustable between 0.3-30 s. Green LED (Un) indicates supply voltage OK. Yellow LED (R) indicates active relay output.



Control relay

1: Over-voltage

2: Hysteresis

3: Under-voltage

4: L1, L2, L3

5: Relay

6: Limit value with time delay for over-/under-voltage




Control relay


spinner symbol


Approvals CE, CSA, RoHS, UL
Breaking capacity 5A, 250V AC/DC
IP Class Connection IP20
IP Class Housing IP30
Lower Limit -2 - -20%
Output 2x Relay
Selection of rated voltage 208, 220, 380, 400, 415, 440, 480V
Supply voltage 3 x 208-480V AC
Temperature range bearing, from -40 °C
Temperature range bearing, to 70 °C
Temperature range from -20 °C
Temperature range to 50 °C
Time Delay On Crossing The Threshold 0,3-30s
Time Delay Start 0,5 s
Upper Limit 2 - 20%
Weight 80 g

Measurements and connections

Technical illustrations

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