Effects of different cutting methods for electrical steel sheets on performance of induction motors

Abstract

In this study, by cutting electrical steel stator laminations, one of the most important components of electrical machines by different cutting methods, the effects of these cutting methods on motor efficiency are investigated. As cutting methods, wire electrical discharge machining, punching, laser and abrasive water jet methods are used. Burr formation at the cutting edge leads to short circuits during the steel packaging and causes magnetic losses in steel packages to increase. In addition, depending on the cutting methods, electrical steel lamination insulation layer is damaged as a result of residual and thermal stress formations. These negative conditions cause iron, friction and windage, stator, rotor and additional load losses occurred in the engine to decrease. In order to minimize these cases, electrical steel stator laminations are cut with the cutting parameters determined as a result of pre-cut tests and 5.5-kW induction motors are manufactured. These manufactured motors, according to IEC 60034-2-1-1B method, are subjected to no-load performance tests in addition to six different loading ratios of 25%-50%-75%-100%-115%-125% and constant 50 Hz frequency. As a result of the test measurements, losses occurred in electrical steels cut with abrasive water jet are found to be higher than the other cutting methods. In addition, in terms of the motor performance, the best results are obtained with wire electrical discharge machining cutting method.

Joining of the Laminated Electrical Steels in Motor Manufacturing: A Review

“…The following model could describe the magnetic flux density degradation because of the motivation of the mechanical stress [ 78 ], , where was the strength of the magnetic field, was the impressed mechanical stress, was the magnetic permeability of a vacuum, was the relative magnetic permeability of the material, reflected the degradation of the magnetic permeability and was the function describing the influence of the mechanical stress on the magnetizability of the material. Other papers also discussed the effects of the microstructure modified by the manufacturing process on the magnetic properties [ 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ]. Generally, the hysteresis loss decreased and excess loss increased with increasing grain size [ 81 , 82 ].…”

Experimental and Numerical Investigations and Optimisation of Grain-Oriented Silicon Steel Mechanical Cutting Process

“…Based on the results, it can be concluded that the deterioration of the magnetic properties of electrical sheets in the areas along the cut line may occur not only in the vicinity of the cut edge, but also in areas located more than 10 mm from the cut edge. For sheets with a high silicon content, deterioration may be up to 15 mm from the cut edge, while for low silicon content, it is about 10 mm [17]. In the works mentioned in Ref [3,19], it was shown that the degradation of the magnetic properties of the material depends on the width of the cut elements.…”

“…The analysis of the state of knowledge shows that the deterioration of the magnetic properties is caused, in addition to the formation of excessive burrs, as well as by the wide deformationaffected zone. The authors of the works mentioned in Ref [17,18] analysed the influence of the width of this zone on the selected magnetic properties of grain-oriented and non-grain-oriented silicon steel. Based on the results, it can be concluded that the deterioration of the magnetic properties of electrical sheets in the areas along the cut line may occur not only in the vicinity of the cut edge, but also in areas located more than 10 mm from the cut edge.…”

Correlation between Cutting Clearance, Deformation Texture, and Magnetic Loss Prediction in Non-Oriented Electrical Steels

“…Among the works on the processing of electrical steels by means of cutting, attention is given mainly to the influence of the cutting procedure (e.g., mechanical, laser, water) on magnetic behaviour [17][18][19]. Previous approaches to identify the characteristics of the cutting process play a crucial role in the optimization of the sheared edge quality investigated the links between various mechanical and geometrical properties such as the burr height, the wear of the cutting tool, and the thickness of a sheet [20,21].…”