An induction motor driving a pump via a flexible coupling shows high vibration at 1X and 2X turning speed, accompanied by a 180-degree phase shift across the coupling. What is the definitive diagnosis?
Answers
ALoose foundation bolts (soft foot)
BRolling element bearing failure
CA bent shaft on the pump
DAngular misalignment between the motor and the pump
Correct answer: D — Angular misalignment between the motor and the pump
Misalignment typically shows up as high 1X and 2X radial/axial vibration. A 180-degree phase shift across the coupling confirms that the shafts are out of alignment, fighting each other.
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