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Motor Unbalance Current
Motor taking unbalance current with kick on the transformer
By K. Yogesh on 17 June, 2016 - 7:08 am

We have 90kW 2 pole motor which was spare for a year. Recently we have taken it for operation. During its DOR confirmation found direction is reverse (NLC; 32/35/33A). So we have changed the orientation of the winding but after that during the direction checking the no load current was imbalance (29/35/30) with the sustained starting kick on the transformer which has caused humming of the transformer. What could be the reason? we have not taken load trial as the equipment was critical.

Suggest to check winding insulation resistance and compare

Thanks & Regards
Venkat