An epoxy powder for transformer wire insulation

An epoxy powder has been developed and successfully used to coat rectangular copper and aluminum wire for transformer application. The powder was designed as a film insulation for transformer windings using an electrostatic cloud coating process. The advantages of powder include a more environmentally acceptable process compared to solvent base coating enamels and a thinner insulation compared to other insulated wire. The coaing process also offers economic advantages as a one coat, high speed operation. A review of the coating powder characteristics and the properties of the insulated conductor is presented. This development was a cooperative effort by the Industrial Electrical Products Division of the 3M Company and the Transformer Divisions of the Westinghouse Electric Corporation.