Behavior of Electrical Insulation Materials and of Halogenated Hydrocarbon Refrigerants at Temperatures of -100° to -200°F

Abstract

The various industries which are now constructing low-temperature refrigeration equipment and the increasingly large number of manufacturers producing air conditioning apparatus have placed a severe demand upon the electric motor manufacturer. Not only must the rotating electrical machinery be housed in hermetically-sealed chambers but it generally must be cooled efficiently with the flow of the refrigerant gas which passes through the windings and rotor of the motor. In many instances the electrical characteristics of the motor must be designed to operate with three-phase, 60 cycle alternating current and frequently at voltages ranging from 600 volts to 2300 volts. The coolant acting upon the windings of these motors will usually consist of Freon compounds and both liquid and gaseous phases will be in contact with the motor windings. The study of the low temperature behavior of the many materials used as effective electrical insulation has become a major research project in the electric motor industry.