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Testing The Ems Soft Starters


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Although the EMS soft starter is getting very old, there are still many giving good service in industry.


To check the performance of the starter, I always begin by connecting three phase on input and three 300 Watt star connected lamps on the output, star connected with the star point isolated from other circuitry. i.e. a three wire circuit.


All three lamps should ramp up evenly to full brightness.

Using a multimeter, ensure that there is full line voltage across each lamp.

Because there is the potential for one SCR to be lazy, measure the voltage forward and reverse.


Best regards,


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Additional considerations:


  1. For Safety Reason......Each leg should be fused with fast acting fuses.
  2. For Safety Reason..... Light bulbs should be enclosed by a wire mesh screen.
    Bulbs can and will explode when least expected.
  3. Use 300-watt bulbs as Mark stated.
    If you use bulbs of lower wattage, you may not draw sufficient current to satisfy
    the Ih (Holding Current parameter) of the SCR's, and they will turn-off.
  4. Strip heater elements could be used instead of light bulbs. Just be sure that they are rated correctly for voltage and minimum wattage required.

Kind regards,

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