The detection and suppression of unbalanced magnetic pull in wound rotor induction motors using pole-specific search coils and auxiliary windings

Dorrell, David G.; Salah, Ahmad A.; Kayani, Obaid

doi:10.1109/ecce.2015.7309699

Cited by 11 publications

(17 citation statements)

References 24 publications

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“…, ( M is the magnetising inductance and ( QR is the airgap leakage inductance. Changing the current fed model in (7) into voltage fed in (8).…”

Section: Static Eccentricitymentioning

confidence: 99%

“…Static eccentricity is caused by the stator core ovality or incorrect positioning of the rotor and the stator at the assembling stage [6]. A small degree of static eccentricity could exist even in newly manufactured machines due to manufacturing and assembly tolerance [ 7 ]. For dynamic eccentricity, the rotor rotates at the centre of the stator bore axis but not on its own axis.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of unbalanced magnetic pull in induction machines through empirical method

Chuan

Shek

2018

IET Electric Power Applications

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Unbalanced Magnetic Pull (UMP) is an important factor to study to improve the reliability of induction machines. UMP occurred in a machine when the existence of rotor eccentricity which causes an uneven distribution of magnetic flux in the airgap. In this study, a UMP damping coefficient is introduced to explain the UMP damping effect from the counteracting flux produced by a parallel connected cage rotor. An empirical method is proposed to calculate the UMP using the damping coefficient and an analytical model. Using the proposed method, a 4-pole and 8-pole squirrel cage induction machine with static eccentricity are investigated, which uses inputs from both Finite Element Analysis and experimental work. Then, the UMP calculation for a dynamic eccentricity with the extracted parameters is done to verify the empirical method. A slip control method is described which uses a UMP/Torque ratio to find the operating slip with the lowest UMP. Comparisons between results with and without slip control are made on both induction machines. It shows that great reduction of UMP can be achieved when the machine is lightly loaded.

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“…, ( M is the magnetising inductance and ( QR is the airgap leakage inductance. Changing the current fed model in (7) into voltage fed in (8).…”

Section: Static Eccentricitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation of unbalanced magnetic pull in induction machines through empirical method

Chuan

Shek

2018

IET Electric Power Applications

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“…However, it is relevant to cage induction machines in terms of commercial system development. In renewable energy, particularly wind turbines, wound rotor induction generators are used and they do not produce the same sideband currents as shown in [25], and [26].…”

Section: A Stator Current Monitoringmentioning

confidence: 99%

Monitoring and damping unbalanced magnetic pull due to eccentricity fault in induction machines: A review

Salah

Guo

Dorrell

2017

2017 20th International Conference on Electrical Machines and Systems (ICEMS)

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Condition monitoring can diagnose the inception of fault mechanisms in induction motors, thus avoiding failure and expensive repairs. Therefore, there is a strong need to develop an efficient condition monitoring. The main target is to achieve a relatively low cost and/or non-invasive system which is still powerful in terms of monitoring for online detection of developing faults. The presented paper addresses rotor eccentricity faults and studies conventional monitoring techniques for induction motors. In order to reduce the unbalanced magnetic pull (UMP) in case of an eccentric rotor, the eccentricitygenerated additional airgap flux waves should be reduced. The radial forces in an induction motor are calculated, and the characteristics of unbalanced magnetic pull are described. Index Terms-condition monitoring, eccentric rotor, induction machines, unbalanced magnetic pull (UMP). Bent rotor Bearing wear Misalignment Detections Methods Stato1• current Axial flux Vibration Torq uc, speed Axial flux Stator current Stator current Vibration Stator current Vibration Axial flux

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“…A simple method in [28] and [44] using pole-specific search coils was introduced and theory was developed to illustrate that rotor eccentricity leads to the generation of airgap flux waves with pole-pairs that are Pm±1. The method was tested using search coils in a four pole wound rotor machine and it was found to successfully indicate the presence of rotor eccentricity.…”

Section: Flux Monitoringmentioning

confidence: 99%

Monitoring and Damping UMP Due Eccentricity Fault in Induction Machines: A Review

Salah

Dorrel

Guo

2016

2016 International Conference of Asian Union of Magnetics Societies (ICAUMS)

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Three-phase induction machines are reliable and widely used in industrial plants. Efficient condition monitoring can diagnose the inception of fault mechanisms in induction motors thus avoiding failure and expensive repairs. Therefore, there is a strong need to develop a more efficient condition monitoring. The main target is to achieve a relatively low cost and/or non-invasive system which is still powerful in terms of monitoring for online detection of developing faults. In order to reduce the unbalanced magnetic pull (UMP) in case of an eccentric rotor, the eccentricity-generated additional airgap flux waves should be reduced. The present paper addresses rotor eccentricity faults and studies conventional monitoring techniques for induction motors. The radial forces in an induction motor are calculated. In addition, the characteristics of UMP in induction machines are stated.

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The detection and suppression of unbalanced magnetic pull in wound rotor induction motors using pole-specific search coils and auxiliary windings

Cited by 11 publications

References 24 publications

Calculation of unbalanced magnetic pull in induction machines through empirical method

Calculation of unbalanced magnetic pull in induction machines through empirical method

Monitoring and damping unbalanced magnetic pull due to eccentricity fault in induction machines: A review

Monitoring and Damping UMP Due Eccentricity Fault in Induction Machines: A Review

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