I have a 30kW motor rated 58A @ 400VAC / 3-phase used for hydraulic pump.
I am using a soft starter to start this motor and the starting current is approx 100A.
The motor is being started before the load engaged, where it is running at 16A only.
My question is since the running current before load engaged is 16A, why my starting current is as high as 100A, which is almost 6.25 times of the running current.
My understanding is that with soft starter, normally the starting current would be 3 to 3.5 times of the running current, right?
Or we should worked out the starting current based on the rated current of motor, which is 58A and NOT the running current of 16A???
So when we size which kW soft starter to be used, should we size based on the motor's rated current on the name plate OR the actual running current?
Please kindly advice, cheers!