Improvements in and relating to the impregnation of windings of electric machines

Abstract

Abstract 465,237. Electric insulation. FRENKEL, E. W., (trading as FRENKEL, H., [Firm of]). July 20, 1936, No. 20086. Convention date, July 19, 1935. [Class 140] Windings of electric machines such as rotor windings are impregnated with a viscous to plastic insulating mass which dries with little loss of weight, consisting of an electrically insulating base e.g. metallic oxides such as zinc oxide or titanium oxide, one or more heat conducting fillers e.g. finely powdered quartz, glass or chalk and a binding agent, e.g. a varnish formed from cellulose derivatives or natural or artificial resins. Colouring agents may be added. An example describes a composition consisting of zinc oxide, chalk, powdered quartz, lead oxide and copalwoodoil varnish. The windings are first dried to remove moisture then brushed with or immersed in the composition, if necessary using pressure or vacuum, and finally dried at temperatures between 90 and 200‹ C.

Inventors

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