Stator Winding Insulation Systems in Current Use

This chapter reviews the state of the art in the manufacturing of random- and form-wound stator coils, and presents the known characteristics of the major commercially available form-wound coil and bar insulation systems. A review of some very recent developments is also presented. One of the interesting trends of the past decade or two has been the merging of many motor and generator manufacturers; accordingly the chapter provides an indicative list of the mergers. In addition, some major brands routinely use other manufacturers to make certain sizes of machines. The insulation systems in current use by most random-wound motor stator suppliers are usually not differentiated by trade names. Instead, most manufacturers use similar materials, although of course manufacturing processes may be different in detail. The chapter describes the main features of current random-wound stators such as magnet wire insulation, phase and ground insulation, and varnish treatment and impregnation.