Current unbalance fault in multi drive lineup.
I have a 1200kw motor for coiling/uncoiling purpose. The motor is driven by a multi drive lineup in which 7no.s of ACS800(580Kva each) drives are used. The drive tripped due to current unbalance 3.Bypassed serialno.3 drive. Run the motor ,again drive tripped due to current unbalance04. Bypassed the serialno.4 drive. Again the fault current unbalance fault came. replaced both the drives with new ones. Again the drivetripped due to the same current unbalance. Changed the APBU card, RMIO card , again the same fault. Meggared the motor , cables found ok. Completely removed both the new drives from the panel & run the drive in reduced run function.Nw motor is running via 5 modules with current limited.
Checked & run the both new drives individually by 30kw motor, found both drives running ok. Taking current up to 68amps.
What is the problem, why this is happening when these drives used in multi drive lineup.
What checks I need to do.?
I can give you the same answer as the previous question: you need to contact the ABB Service of your geographic area, because the description of the failure is IMHO to complex and can not be solved with a simple suggestion in the forum.
Having no complete overview of your plant / machine, I can not give you false / incorrect suggestions.