Copper motor rotors: Energy saving efficiency, now also economic feasibility

Abstract

Replacing aluminum with copper in the die cast squirrel cage conductor bars in electric induction motor rotors has enormous potential benefit in terms of improved efficiency, energy savings, reduced maintenance and reduced weight and cost. Energy savings in the US alone can eventually exceed the output of three to four new 600 megawatt generating plants. The major deterrent to that conversion has been the short tool life associated with casting molten copper. Research sponsored by the Copper Development Association has identified recommended tool materials and casting practices that significantly improve tool life. TBT Presses, Inc. has developed a vertical die casting machine with design features especially suitable for casting motor rotors, and have demonstrated capability to cast a wide range of copper motor sizes on that equipment. They now cast copper-alloy motor rotors for customer evaluation and for limited-volume production runs. THT's Sub Liquidus rheocasting process provides future opportunity for even better tool life when die casting copper alloys.

Induction motors with copper rotor: a new opportunity for increasing motor efficiency

“…Similarly, building other motor parts for similar reasons may have different costs. Analyzing the economic and operational feasibility of a specific manufacturer can lead to erroneous conclusions when installing a CURIM from other manufacturers, even if it is the same type of machine [7], [8], [21]. Thus, the analysis should be done by varying the list prices in a specific interval.…”

“…With the improvements achieved by these methods, die thousands of cycles have increased life, production costs have been reduced, and product quality [8]. Table 1 shows the average loss segregation in seven CURIMs of 11.2 kW, tested by a manufacturer, using the IEEE specification 112 standards test method B [5], [7]- [9].…”

Automotive Electric Propulsion Systems With Reduced or No Permanent Magnets: An Overview

“…Casting copper cages is a relatively new technology, and the economic case for them was put forward in [45]. They may appear to be the way forward, but alternative arrangements have been studied.…”