Diecast Copper Rotors Improve Motor Efficiency

摘要

Electric motors consume so much energy that a 1 percent increase in motor efficiency would save 20 billion kWh/yr. (more than 1 billion dollar in electricity) with accompanying decreases in air contamination and contribution to global warming. High electrical conductivity of copper in the rotor structure of an induction motor can achieve an 11-19 percent reduction in overall energy losses by increasing energy efficiency, however, diecasting a copper-base rotor is challenging. High pressure diecasting is the most economical process to form the squirrel cage of the induction motor rotor. However, copper-base alloys (despite their fluidity which makes them ideal for diecasting) have a high melting temperature that leads to a shorter diecasting die (tool) life and increased costs. As a result, diecast aluminum rotors have been used in most small and medium-sized integral horsepower motors even though copper is the logical material of choice.