Tripping of Feed Pump

Obviously soft starter problem.Try and by-pass the soft starter with ordinary starter and observe results for one or two days.

i had bypass the soft stater by putting a timer with 15 sec. time after getting start by same & solve the problem

These numbers are somewhat confusing. 110 kw ≈ 150 hp. A 460/3/60 motor would draw about 180A, a 230/3/60 motor about 360A. The unbalance on a new motor does make the soft starter look suspect, as Ramvinod notes. Or possibly a wiring fault such as moisture in the insulation. Some megohm testing would be in order.

This sounds like a wiring problem to me. Disconnect the wires at both end and megger them to ground. Sounds like you have a phase conductor partially shorted to ground that is sucking off current.

What are you pumping what is the mechanical conditions present?

Is soft starter in series with motor power supply from it's MCC feeder during normal running of motor? If it so ,then Soft starter is a culprit, since soft starter's current out put is not balanced as mentioned by you.

Tripping always occurs when current higher than should be. It might happen that the resistance to flow in the installation is lower that predicted. That would cause feeding more than the feed that is normal, which always increases power consumption by motor driving the pump. You have two options: one on electrical side and another on hydraulic side:

Hydraulic side: Place Orifice in the flange of the suction part of the pump. Proper size would probably be aperture 90% of the flange aperture.

Electric side: Increase level of the tripping current by 10%.

Proper way would involve flow measure vs current of motor and finding out what to do!

Good luck as it is to late for knowledge for you!

Advise is not to trust what I wrote, as I do not have any idea about your system. This problem might relate to wrong selection of trip for the range of the operation of your pump.

Is soft starter in series with motor power supply from it's MCC feeder during normal running of motor? If it so ,then Soft starter is a culprit, since soft starter's current out put is not balanced as mentioned by you.

AGAIN,

That soft starter has integral bypass contacts. At the end of ramp, i.e. 10-30 seconds later, the bypass contacts close AND THE SOFT STARTER IS NO DIFFERENT THAN A DOL STARTER. Nothing the soft starter does, or doesn't do, is going to affect the tripping 2-3 hours into it.

Good point - check one or more of the bypass contacts are not cooked.

Yet one more time... no further input from a "guest" after posting a question asking for aid and receiving responses from the community.

Me thinks in the future, I will ignore requests from guests.

Thanx to all my friends for reply

my office IP was Blocked i don't know way

i had put a new soft stater in place of old

and problem solved