Use the following procedures to assess and correct current unbalance. Current unbalance can be due to the motor or the supply line. To determine the source, arbitrarily label the supply lines A, B, and C — and the motor leads 1, 2, and 3. Then connect A to 1, B to 2, and C to 3, operate the motor, and measure the current in each line. Next, de-energize the motor and connect A to 3, B to 1, and C to 2, operate the motor, and again measure the current in each line.
read more