Investigation of Ceramic-coated Profile Conductors Regarding Insulation Strength with the Aim of Better Thermal Connection to the Laminated Core of Electrical Machines

Abstract

This work addresses an alternative approach to electrical insulation of the winding by using ceramic materials such as aluminum oxide, which in addition to good insulation strength also have relatively high thermal conductivity. This can be applied to copper by thermal spray processes, which also allow the use of profiled conductors. In the present work, the determined values for insulation strength and insulation resistance are presented depending on different layer thicknesses and manufacturing parameters, as well as the influence of posttreatments. For this purpose, a special measurement setup is used which records the corresponding data with a large number of contact points and thus takes into account weak points caused by manufacturing variations.

Development of Polymer-Ceramic Composite Materials for the Winding Insulation of Highly Utilized and Energy-Efficient Electrical Machines

“…Such wire coatings are currently of increasing interest for high-temperature applications in the aerospace sector, whereby the mechanical and electrical load capacity is still limited due to the brittleness of the ceramics [14], [15] however. In addition to Cu/Ni wires [16] - [18], development is currently also focusing on thermal spray coating with Al2O3 [19]. There are also initial approaches to electrochemical coating of lamination stacks, with thermal conductivities of the insulation of up to 2 W/(mꞏK) and temperature stability of up to 300 °C being achieved [20].…”