Why Is My Electric Motor Vibrating? 6 Common Causes and Fixes

Excessive vibration is one of the most common problems plant engineers face with three-phase induction motors. Left unaddressed, it loosens foundation bolts, wears couplings, destroys bearings, and can eventually lead to stator-rotor rubbing and winding failure. This guide walks through the six most common causes and how to fix them, in the order you should check them on site.

1. Is It an Electrical Vibration or a Mechanical One?

A quick on-site test narrows the field. Turn off the power and rotate the shaft by hand: if the motor already feels rough or out of balance, the cause is mechanical. If the vibration only appears once energized and drops sharply the moment power is cut, look for an electrical cause.

2. Six Common Causes and Fixes

3. How Much Vibration Is Acceptable?

For general-purpose low-voltage induction motors, the vibration velocity at the bearing housing should generally stay below 2.8 mm/s RMS per ISO 10816 (flexible mounting). If readings are consistently above 4.5 mm/s, shut the motor down and investigate rather than running it to failure.

4. Short-Term Fix and Long-Term Practice

In an emergency, tighten the base, check alignment, and listen to the bearings. But the real cure is preventive maintenance: trend vibration readings over time. In hazardous areas such as chemical plants and mines, specify a YBX3 flameproof motor, whose rigid frame and oversized bearing housings give much steadier long-term operation.

SHANGDIAN (Shanghai Electric Motor Factory) manufactures YE3/YE4/YE5 premium-efficiency low-voltage motors, each factory-tested for vibration and dynamic balance. If you are selecting a motor for pumps, fans, crushers or similar drives, contact us for selection support and on-site diagnosis.