Improvements in energy efficiency of induction motors by the use of magnetic wedges

Curiac, Radu; Li, Harry

doi:10.1109/pcicon.2011.6085890

Cited by 31 publications

(15 citation statements)

References 10 publications

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“…The benefits of using magnetic stator wedges are -the smoothing of the air-gap flux, improved efficiency and reduced temperature rise [26]. With stator wedges being made out of magnetic material they will vibrate under the effect of rotating fields causing the weakening of the stator wedge bonding.…”

Section: B Failure Mechanisms In Generatorsmentioning

confidence: 99%

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A Review of Methods to Increase the Availability of Wind Turbine Generator Systems

Shipurkar¹,

Polinder²,

Ferreira³

2016

CPSS TPEA

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Abstract-Availability is an important factor to be considered when designing wind turbine generator systems. The quest for increased availability is based on the following five design approaches -design for component reliability, active control for reliability, design for fault tolerance, prognostics, and design for maintainability. This paper reviews methods focussing on the first three, i.e. component reliability, active control, and fault tolerance. The paper further identifies some promising directions for further research.

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Section: B Failure Mechanisms In Generatorsmentioning

confidence: 99%

“…Magnetic wedges offer a number of improvements to machines resulting in increased efficiency [109], [26], [110]. However, looking at their propensity to failure in wind turbines, it may be important to look at their impact once again.…”

Section: ) Magnetic Stator Wedgesmentioning

confidence: 99%

A Review of Methods to Increase the Availability of Wind Turbine Generator Systems

Shipurkar¹,

Polinder²,

Ferreira³

2016

CPSS TPEA

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“…This leads to reduced torque ripple. The drawbacks on the other hand are an increased slot leakage flux, which leads to a decrease of the average torque values, and a decreasing robustness with increasing permeability [19].…”

Section: Magnetic Slot Wedgesmentioning

confidence: 99%

“…A general conclusion on the applicability of MWs is difficult to make. Most investigations conclude that the right choice of material property and wedge design is essential for the effect of the magnetic slot wedges [13] - [19].…”

Section: Magnetic Slot Wedgesmentioning

confidence: 99%

Torque ripple reduction in permanent magnet synchronous machines with concentrated windings and pre-wound coils

Richnow

Gerling

Stenzel³

2014

2014 17th International Conference on Electrical Machines and Systems (ICEMS)

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Ideally, improvements of the manufacturing process do not cause deteriorations of the product characteristics. Pre-wound coils for electrical machines with concentrated windings are such an improvement. The easiest way to enable the assembling of pre-wound coils is simply the absence of pole shoes. This paper discusses the absence of pole shoes based on a sample machine. The focus lies on changes of cogging, avg. nominal and peak torque and the occurring torque ripple. Furthermore, different technologies as a variation of the tooth thickness, skewing, magnetic slot wedges and plug-in connections are investigated to compensate deteriorations of torque behavior. In addition, the effects of these technologies on the manufacturing process of a stator are discussed.

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“…The properties of the wedge material strongly influence the starting behavior of the machine [ 2 ]. Investigations have shown that the material must be of low conductivity and high permeability [3].…”

mentioning

confidence: 99%

Detecting partially fallen-out magnetic slot wedges in AC machines based on electrical quantities only

Stojcic

Magnet

Joksimović

et al. 2012

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society

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The winding system of high voltage machines is usually composed of pre-formed coils. To facilitate the winding fitting process stator slots are usually wide opened. These wide opened slots are known to cause disturbances of the magnetic field distribution. Thus losses are increased and machine's efficiency is reduced. A common way to counteract this drawback is given by placing magnetic slot wedges in the slots. During operation the wedges are exposed to high magnetic and mechanical forces. As a consequence wedges can get loose and finally fall out into the air-gap. State-of-the-art missing slot wedge detection techniques deal with the drawback that the machine must be disassembled, what is usually very time consuming. In this paper a method is investigated which provides the possibility of detecting missing magnetic slot wedges based only on measurement of electrical quantities and without machine disassembling. The method is based on exploitation of machine reaction on transient voltage excitation. The resulting current response contains information on machine's magnetic state. This information is composed of several machine asymmetries including the fault (missing wedge) induced asymmetry. A specific signal processing chain provides a distinct separation of all asymmetry components and delivers a high sensitive fault indicator. Measurements for several fault cases are presented and discussed. A sensitivity analysis shows the high accuracy of the method and the ability to detect even partially missing slot wedges.

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Improvements in energy efficiency of induction motors by the use of magnetic wedges

Cited by 31 publications

References 10 publications

A Review of Methods to Increase the Availability of Wind Turbine Generator Systems

A Review of Methods to Increase the Availability of Wind Turbine Generator Systems

Torque ripple reduction in permanent magnet synchronous machines with concentrated windings and pre-wound coils

Detecting partially fallen-out magnetic slot wedges in AC machines based on electrical quantities only

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