Inverters are now widely used,with mature technology and ease of operation.Even without relevant technical knowledge,they can be learned quickly.However,various problems can still arise during use due to various reasons.Many inverters have built-in alarm functions that provide corresponding fault causes and solutions.Here's a simple analysis of a recent issue encountered:abnormal noise from a motor driven by an inverter.

The first reason is due to the inverter's carrier frequency.This has been extensively analyzed online. Simply put,this is caused by harmonics on the inverter's output side,generating high-frequency noise within the motor.This can be reduced or eliminated by adjusting the inverter's carrier frequency.However,the carrier frequency should not be too high,as an excessively high carrier frequency will cause the IGBT switching frequency on the output side to be too high,damaging its electrical lifespan.

The second reason is due to problems with the motor itself.Motors are electromechanical products,and faults can occur in both electrical and mechanical components.In one case, a mature machine,during commissioning,would periodically emit abnormal noise after running for more than an hour,with the noise increasing in intensity.Stopping and restarting the machine after the noise appeared did not resolve the issue.Unless the motor has cooled down,the inverter is largely ruled out as the cause.Based on the above,the problem was determined to be either with the motor itself or the support bearing housing (the shaft end connected to the motor output shaft via a coupling has a self-made bearing housing).The noise reappeared on-site,and by listening to the noise from both ends of the motor and the support bearing housing, and measuring the temperature at various points,abnormal noise was found at the motor output shaft end.This confirmed a quality problem with the bearing at the motor output end.After repair, the abnormal motor noise was resolved.

Through the above,it can be determined that the abnormal noise was caused by the inverter driving the motor.Based on the noise characteristics and specific conditions under which it occurred,a preliminary judgment was made as to whether it was an electrical or mechanical fault.Based on the preliminary judgment,the noise source was analyzed, located,and confirmed, and finally eliminated.