GE QS2800V, QS1800V manual Figure

3.6.3Three-Phase Power Imbalance

Current imbalance should not exceed 5% of the average three-phase current. The current imbalance can be calculated as follows:

STEPS

1.Measure the current through each of the three legs.

2.Determine the average of the three currents.

3.Determine the difference between the current in each leg and the average of all three legs.

4.Take the difference with the largest value, and divide it by the average current. Multiply by 100 to obtain the current imbalance percentage.

5.If the current imbalance is greater than 5%, “roll” the leads and re-test (Figure 3.7, “Rolling” the Leads to Balance Current Draw). If “rolling” the leads does not correct the problem, the source of the imbalance must be located and corrected. For more information on current imbal- ance, refer to the motor operation manual.

Figure 3.7

“Rolling” the Leads to Balance Current Draw

3.6.4Wire Sizing

For correct power lead sizing from the power source to controls and motor, refer to the motor installation manual or local electrical codes.

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