Thanks Marke, We have swapped the motor twice, swapped the CT's three times, swapped the contactor twice, swapped the cable twice, We used the similar motor's supply to run the tripping one and the motor did not trip, when we connect it back and supply another motor with a different cable from...
To answer edison123 question, there is no capacitor connected. I have a theory and I'd like to hear your opinion on it.: Could it be the interturn fault on the transformer that causes this, suppose at high starting current you could be having curculating current on the winding which result in...
Thank you all for the input. We've been working on this problem again today. First of all just to answer some of your questions, the motor is a DOL start, the current unbalance relay is set at 3Amps there is no time delay on the relay it is instantaneous and this is applicable to all three...
The system has worked ok for a very long time and there has been changes on some components on the switchboard but that was long b4 the problem started. Like I said there are three motors of the same rating and every thing is the same on all three of the except they are supplied from different...
We have three phase induction 160kW each motors driving pumps to pump water. One of the motors is tripping on current imbalance during startup. The motor is supplied from the switchboard by the transformer. We have changed the motor have changed the CT's we have changed the relay, we have...
