Effects of the Slot Harmonics on the Stator Current in an Induction Motor with Bearing Fault

Xiangjin Song,Hongyu Zhu,Jilong Zhang,Jingtao Hu

doi:10.1155/2017/2640796

Abstract

Bearing faults are the most frequent faults of induction motors. The current spectrum analysis is an easy and popular method for the monitoring and detection of bearing faults. After a presentation of the existing fault models, this paper illustrates an analytical approach to evaluate the effects of the slot harmonics on the stator current in an induction motor with bearing fault. Simple and clear theoretical analysis results in some new current characteristic frequencies. Experimental tests with artificial bearing outer raceway fault are carried out by measuring stator current signals. The experimental results by spectral analysis of the stator current agree well with the theoretical inference.

Highlights

Induction motors (IMs) play a critical role in agricultural, industrial, and commercial sectors
In a rolling-element bearing, artificially produced defect is introduced by drilling a hole in the outer raceway to simulate a localized fault, which is similar to other literatures [9,10,11,12]
This section is divided into two parts: first, an overview of the experiment test rig is presented, and the proposed techniques are verified offline using stator current signals for bearing outer race fault detection

Summary

Introduction

Induction motors (IMs) play a critical role in agricultural, industrial, and commercial sectors. Vibration signals have been widely applied in IM bearing faults detection [3,4,5,6] This method is invasive and needs to install special sensor on the motor. The aforementioned models, neglected rotor and stator slotting effects which modify the valid airgap permeance. These techniques may lead to unreliable IM fault diagnosis. In view of the advantages of the aforementioned models, together with the effects of rotor and stator slotting, a more comprehensive mathematical model is proposed in this paper based on rotating wave approach where airgap flux density is determined by the product of permeance and magneto-motive force waves.

The Structure and Fault Types of a Rolling-Element Bearing

Current Characteristics Analysis Theory

Experimental Results

Conclusions