EMU-25 MCB circuit breaker tester

EMU-25 MCB circuit breaker tester

Electronic AC Current Injector up to 25A

The EMU-25 is a completely electronic unit.


The following gives more details of this testing unit:

  • Complete computer control with its corresponding software and communication board, RS-485. The program has the possibility to control up to 15 units at the same time.
  • The unit generates a digital wave-form, from a oscillating quartz and adjust this wave in 1024 point/cycle which insures the exact frequency and very low distortion.
  • The reference amplitude in d.c. and the selection by a DAC of 12 bits, allows a continued feedback, comparing the output level with the reference and activates a signal which controls the power amplifier, to insure a perfect stabilized and accurate output, even though there are variations in the load, power supply, etc.
  • The power module is compact, with forced ventilation and contains an auto power switch which gives the maximum power required in relation to the load. This achieves a very efficient output and low dissipation.
  • The transformer load coupled to the power amplifier, allows an galvanic insulation and perfect joining of this load.
  • Computer control of an external element up to 220V (ex. auxiliary contact).
  • The unit contains an output overload, thermal, and auxiliary power supply alarms as well as a connector for an d.c. measuring instrument, for easy verification.


  • Regulation 0 – 25A a.c.
  • Nominal power: 300VA.
  • Can be connected in parallel.
  • Input for external phase and/or frecuency reference.
  • Computer controlled by serial port RS-485 (adapted to RS-232)
  • Overload, overheating alarm leds.
  • Rack mounting 19″ (482 mm).
  • Accuracy: ±1%.
  • Distortion: <1%.


  • To test small circuit breakers.
  • Calibration of shunts and measurement instruments.
  • To test thermic relays which require a long duration.
  • Overheating test.
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