Why motor bearings have ringing rings?

Three phase motor bearings play a vital role in the smooth operation of machinery, and understanding their behavior is critical for effective maintenance and performance. A common phenomenon in motor bearings is “circling,” which occurs due to the fit between the bearing, shaft, and bearing chamber. This fit is usually a clearance fit that allows a certain amount of movement between the parts.

When the motor is running, torsional forces destroy the relative static state of the bearing assembly. This damage can cause slippage between components, especially between the inner ring of the bearing and the shaft, a phenomenon known as “inner ring slippage.” Similarly, sliding occurs between the bearing outer ring and the bearing chamber, which is called “outer ring running”. Both types of sliding can significantly affect bearing performance and life.

The main reason three phase induction motor bearings run in circles is the imbalance created by these sliding actions. When the inner ring slides relative to the shaft, it causes uneven wear, causing the bearing to lose alignment. This misalignment intensifies sliding motion, creating a feedback loop that further destabilizes the bearing position. As a result, the bearings may not rotate smoothly, causing vibration and potential failure.

In addition, factors such as lubrication, load conditions and temperature can affect the degree of sliding and the overall performance of the bearing. Proper maintenance, including regular inspections and timely lubrication, can help alleviate these problems and ensure bearings operate within their design parameters.

To sum up, the ringing phenomenon in 3 phase asynchronous motor bearings is mainly caused by the clearance fit between the bearing, shaft and bearing chamber, plus the sliding caused by torque. Understanding these dynamics is critical to maintaining optimal motor performance and extending bearing life.