I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?

also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same on all legs with non-VFD machines. ?

the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP