Impact of Rotor Imbalance on Electric Motor Performance

What Are the Effects of Rotor Imbalance on Motor Quality?

1)Causes of Rotor Imbalance Vibration:

•Residual imbalance from manufacturing

•Accumulation of dust due to prolonged operation

•Thermal stress causing shaft bending during operation

•Thermal displacement of rotor components leading to imbalance

•Centrifugal force from rotor components causing deformation or eccentricity

•External forces (such as belts, gears, poor direct coupling, etc.) causing shaft bending

•Poor bearing installation (precision of the shaft or locking) leading to shaft bending or internal deformation of the bearing

2)How to Control Rotor Imbalance:

•Maintain imbalance within the allowable limits

•Improve the tight fit between the shaft and core

•Address anisotropy of thermal expansion

•Design improvements

•Strengthening design or assembly improvements

•Correct shaft strength design

•Changing the type of shaft couplings and correcting direct coupling to the center

•Prevent misalignment of bearing end faces and shaft attachment parts or locking nuts

3)Causes of Abnormal Vibration and Noise in Bearings:

•Internal damage to the bearing

•Abnormal axial direction vibration of the bearing

•Axial spring constant and rotor mass composition creating an excitation system for vibration

•Poor lubrication and bearing clearance issues in cylindrical roller bearings or large diameter high-speed ball bearings

4)Bearing Replacement:

•Apply appropriate axial spring preload to accommodate bearing clearance changes

•Choose soft grease or low-temperature performance grease

•Minimize residual clearance (attention must be given to temperature rise)

5)Rotor Dynamic Balance Correction Method:

•After measuring the rotor's dynamic balance on a balancing machine, balance correction can be performed using either weight addition or weight removal methods:

•Weight Addition Method: Add a corrective weight in the opposite direction of the imbalance. Common methods include welding, soldering, riveting, screwing, or adding weights.

•Weight Removal Method: Remove a certain amount of weight in the imbalance direction. Common methods include boring, drilling, chiseling, milling, and grinding.

Choose Germana for Your Business Success!