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Home > Industry > Switchgear > Control, Display and Operate > Measuring and Monitoring Relays > Phase Monitor

EMR4-W Phase Monitor Destruction/Damage Protection for Individual System Sections

Phase Monitor EMR4-W phase monitors are used for monitoring the phase sequence and the applied voltage level, thus offering protection against destruction or damage to individual system sections. A dial allows easy setting of the required voltage for both the minimum undervoltage and maximum overvoltage within a defined window.

Both on-delayed and off-delayed functions are possible. The on-delayed setting enables short overvoltages or voltage dips to be bridged. The off-delay setting allows faults to be stored for the time set.

The delay time can be set between 0.1 s and 10 s. The relay picks up if the phase sequence and the voltage are correct. After it has dropped out, the device does not pick up again until the voltage goes over a 5 % hysteresis.


  • Phase sequence detection
  • Phase loss detection at U < 0.6 x Ue
  • LED status indication
  • The relay features a second changeover contact that is used for indication purposes
  • 2 versions for monitoring voltage U = 300-500 V AC and 350-580 V AC
  • Either on or off-delay (0.1 s 10 s).


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