Topologies of High Temperature Machines

The paper deals with machines able to operate in high temperature (HT°) environments. Most of standard machines are made with enameled wires insulated with a thin polymer layer. With the best available enameled wires, the organic nature the winding insulation limits the operating temperature to about 280°C at the hottest point. Therefore, standard machines cannot be used in the hot environments of specific applications such as deep drilling in petroleum industry, geothermal equipment or near aircraft turbines. Recent studies show that an inorganic insulation technology, made without any polymer, can push this thermal limit up to 500°C. After presenting an overview of the available HT° insulation technologies, the paper details the possible topologies of HT° machines and their limits.