The Journal of Engineering (Apr 2019)
Investigation of wire insulation for high-temperature motor windings
Abstract
There is a strong interest in the development of high-temperature electrical machines, both from academic research and industrial consumers. Conventional electrical machines cannot operate much beyond 250°C, and this limits their application in certain sectors such as oil, gas, and aerospace. The key technology for high-temperature operation is high-temperature wire insulation systems for the motor windings. This study presents an experimental study on the temperature dependence of the wire insulation resistance of a standard Class H (180°C) enamel wire, a high-temperature MAGNETEMP CA-200 wire, a photonis glass-coated wire, a mica-taped VonRoll SK650 wire, a ceramic-based CERAFIL500 wire, and a newly developed S-2 glass-fibre insulated wire. The results show that motor operation above ∼300°C for any length of time using conventional polymer-based wire is difficult. It is possible, however, to operate motors up to 600°C using inorganic insulation coatings. The new wire using the S-2 glass-fibre insulation performed very well showing good insulation resistance up to 600°C: excellent flexibility and robustness, capable of very small bend diameters, and with packing factors almost identical to the conventional copper wire.
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