Copper in the squirrel cage for improved motor performance

The advantages to motor performance and energy efficiency or substituting copper for aluminum in the squirrel cage of the induction motor rotor are described in this paper. Performance data on motors equipped with die-cast copper rotors dynamometer tested by several motor manufacturers according to IEEE Specification 112B are presented. Overall motor losses were 14 to 23% lower in motors with copper rotors compared to the aluminum counterparts. The manufacturing technology for economical production of copper rotors by die casting has also been investigated and is summarized. Use of a nickel-base alloy high temperature die operated at elevated temperature is shown to greatly extend die life over that experienced with conventional die steels in die casting copper with its high melting temperature.