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Phase Loss Trips


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If the starter trips occasionally on phase loss, determine if there is a genuine phase imbalance condition occurring intermittently, and if so, try to correct the situation.

If the problem can not be fixed, then you can desensitize the starter by increasing the setting in parameter 7.

Maximum sensitivity is at a setting of 1 and minimum sensitivity is at a setting of 10.


If the problem continues with a setting of 10, and there is no current imbalance, it is probable that there is a fault on the control pcb.


The control pcbs are identical for all EMX and EMX2 models and can be swapped between units without any reprogramming.

Swap the main control pcb between two starters and see if the problem moves.


Best regards,

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The EMX and EMX2 starters are a closed loop controlled current soft starters which utilize external ring type current transformers (CT's) for the purpose of current measurement.


In addition to the information presented by Marke, it is wise to confirm that there are no loose connections in the secondary CT cabling. Check the integrity of electronic components and solder joints on the PCB to which the CT terminal strip connects is also suggested.


It is my humble opinion that the above-mentioned checks be performed before altering the setting of function 7 or swapping PCB's.




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Good points GGOSS

I always ask those questions, but forgot to add them to the list here.

I rarely find any issues with the CT wireing etc except where there is an external earth attached.


- DO NOT connect an external earth to the CT secondaries!


Best regards,

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