Testing & TroubleshootingQuestion 495 of 521
A newly connected three-phase motor runs backward. What is the standard corrective action?
a.Reverse all three line leads at the motor
b.Add a phase-shifting capacitor to one leg
c.Interchange any two of the three line leads
d.Increase the supply voltage by 10%
Explanation
Swapping any two of the three phase conductors reverses the rotation of the motor's rotating magnetic field, so the motor turns the correct way. Reversing all three (a) leaves rotation unchanged. A capacitor (b) and higher voltage (d) do not change phase sequence.
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