What is the maximum current unbalance of a 3 phase motor?

No standard prescribes permitted unbalance in current for induction motors. IEC 892/2002 however, specifies permitted unbalance in voltage as 1% at the motor terminal. It is deduced that 1% unbalance in voltage will result in 6% to 9% unbalance in current. This is, therefore, grid caused activity. However, there are load related activities, such as parallel connected single phase loads or shunt capacitors that may also influence unbalance in current across the main contactor. In large motors, sometimes, unbalance in current can be seen if the air-gap eccentricity is seen. In such cases the PF in 3 phases will be unbalanced.