Review of the developments in processing and joining of electrical steel sheets for the stator core of electric motors

The electrical steel sheets are the preferred choice for the stator cores used in electric machines. They are commonly termed as Fe-Si alloys or silicon steel. There are two prominent categories of electrical steel involving: Cold Rolled Grain Oriented (CRGO) and Cold Rolled Non-Grain Oriented (CRNO) steel. The stator components commonly consist of stacked thin sheets of 0.5 mm thickness (CRNO) which are coated. These staked sheets are processed using several techniques depending on the user’s requirements. Though there are several techniques suggested for the development of stator cores, it is recommended to adhere to only those techniques which are less disastrous for the cores from the view of energy saving. This paper reviews the current start of the art in the processing and joining of the CRNO grade thin electrical steel sheets for stator core including the impact of different manufacturing processes used for transforming the raw sheets into the final core structures. It also includes the findings from several studies ­performed by researchers across the world for the processing of electrical steel sheets along with their end results. It also presents the alternative manufacturing techniques (separation joining, etc.) suggested for stator cores and their effects on the physical and magnetic performance of electrical steel sheets. The article also systematically covers several techniques, diagnostic methods, and effective processing alternatives for the electrical steel sheets.