An evaluation of inductances of a salient pole synchronous machine under different axial eccentricity conditions

Abstract

SUMMARY Different radial eccentricities in salient pole machine are well documented in previous studies. In reality, the most probable case is the rotor eccentricity, which is not uniform down the axial length. This article determines a precise model of salient pole synchronous machine for general axial eccentricity condition. Proposed model allows calculating salient pole machine inductances with different static, dynamic, and mixed axial eccentricities in a unified technique. By taking into account machine geometry, slots effects, and type of winding connection, this model is able to consider most of the important features of a salient pole machine. A variant of modified winding unction approach has been used to calculate the inductances under axial eccentricity conditions. The effects of several rotor asymmetries on the inductances are shown, and the inductances are evaluated. The evaluated inductances are compared with those obtained from experiments. There is a good agreement between the simulated and the experimental inductances profiles. Copyright © 2012 John Wiley & Sons, Ltd.

Analysis and effect of static eccentricity fault on performance indicators of a synchronous reluctance motor

“…The WFM is mostly adopted for a healthy machines whose air gap is symmetrical or uniform [3,15]. The MWFM is largely adopted for faulty machines since it accounts for air gap eccentricity [5,17,18]. The work of [29] revealed that Modified Winding Function Theory (MWFTh) is generally accepted in analyzing rotating electrical machines which have a very small air gap.…”

“…Majority of the researchers who investigated faulty machines patronized this method. The calculations of inductances of salient-pole synchronous motor operating under eccentricity using MWFTh were done by [17,20] and [21]. Again [21] developed an analytical model that can compute the machine inductances under any kind of eccentricity.…”

A new analytical technique for analysis and detection of air-gap eccentricity fault in surface-mounted permanent-magnet machines

“…Detection of the eccentricity fault in induction machines and synchronous generators has been the subject of many papers. New machines and drives need more precise, quick, and easy fault diagnosis methods, so mechanical faults such as eccentricity fault and magnetic faults such as demagnetization fault in permanent‐magnet (PM) machines have been widely studied in order to find more accurate and simpler diagnosis methods.…”

Real‐time condition monitoring on VSD‐fed induction motors through statistical analysis and synchronous speed observation

“…The introduced approach uses standard statistical analyses like mean, variance, and information entropy, on one phase of the steady-state current signal provided by the VSD, together with sensorless synchronous speed estimation from the stator voltage supply, as inputs to an ANN for classifying the induction motor operational condition, different from reviewed literature, where a direct connection of the motor to the power supply is considered for simplicity and improved certainty of the used approach during the fault detection process. The introduced technique is able to detect distinct faults like BRB, misalignment (MAL), and unbalance (UNB) at different rotating speed, unlike previous approaches that detect just one single fault as bearings [6][7][8], rotor bars [9][10][11][12][13], and UNB [14][15][16][17][18] at a fixed rotating speed. Previous methods in reviewed literature use computationally complex signal processing techniques like WT [19][20][21][22][23], FT [24][25][26][27], and their combination with other techniques [28][29][30][31][32][33][34][35][36][37] for detecting multiple faults, which restrain them to off-line applications.…”

“…Differently, in , unbalance in induction generators is detected by using the ratio of active power to apparent power (power factor) as a condition monitoring criterion. The effects of axial eccentricities, as rotor asymmetries, on the machine inductances are studied in . The effects on rotor vibrations of design, manufacturing, and external factors, like mechanical unbalance, are presented and discussed in .…”