Impact of core sheet cutting method on parameters of induction motors

Abstract

The method of cutting motor core sheets causes a change in their magnetic properties and core losses, especially additional losses. Reducing motor losses is very important because of the fulfillment of increasingly stringent requirements set by international regulations for reducing electricity consumption. Due to fact that more and more often induction motors are supplied with high-frequency voltage, core losses are beginning to play a dominant role in the motor's loss balance. That is why accurate determination of these losses is very important and cutting has a significant impact on them. This report shows how the method of cutting sheet metal affects losses in the finished induction motor working in a wide frequency range. The paper presents the impact of various motor core fabrication technologies on its operational parameters and an approximate way of including this impact in analytical calculations at the design stage of new machine designs, as it is necessary to use sheet metal cutting technologies such as laser or electrical discharge machining (EDM) at the prototype stage. The proposed method is based on measurements of sheet parameters made on toroidal samples with appropriately selected dimensions, so that the width of the sample corresponds to the average width of the motor core elements.