Ims2 - Low Start Current, Will Not Start Motor

[marke]

Today I had a call from a user who had replaced an older IMS2 with a new one and it would not start the pump.

 

The current was set up for the full load current of the motor and the start current was set for 350%.

 

When the start was called, the motor attempeted to start, but did not even rotate.

The start current was about 50% of the rated FLC of the motor.

 

The wiring was exactly as per the original failed IMS2 and the programming was reportedly the same.

 

The problem was that there was a Normally Closed external trip circuit connected the programmable input on the soft starter.

The default setting for this input is to switch to the secondary parameter set and this had not been reprogrammed to the normaly closed trip function. The soft starter was starting to the settings in the secondary set which was set up for a full load current of only 8 Amps and so it drew 28 amps at start. (350% x 8A)

 

Solution : reprogram the programmable input to the correct function.