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The manufacture of electric motors with die-cast copper rotors is one of the most exciting engineering developments led by the Copper Development Association (CDA) in recent years. While the benefits of replacing aluminum rotors with copper have been known for some time, casting copper rotors economically had been the biggest hurdle to overcome. Therefore, it was no surprise when a particularly determined owner of a small die casting business in India contacted Copper Motor Rotor Project Manager Dr. John Cowie for some guidance with his company's trials to cast copper rotors.
"About 10 years ago we learned of the advantages of copper rotors," explained Mr. Akhtar Hussain G. Ajmearwala, owner and operator of Perfect Die Cast in Gujarat, India. "But, at that time, people believed that die casting copper rotors was not possible at all." Determined to prove this belief wrong, Mr. Ajmearwala's father, the founder of Perfect Die Cast, made the company's first attempts to cast copper rotors. However, he was unsuccessful. Undaunted, the younger Mr. Ajmearwala built upon his father's research. "After years of slow trials I found your Web site, copper-motor-rotor.org. It gave us new confidence that it is possible to die cast rotors in copper," he said.
When Mr. Ajmearwala contacted Dr. Cowie earlier this year, Dr. Cowie had been overseeing CDA's trials for over three years. "When Mr. Ajmearwala starting talking about problems with oxidation and cracking, I knew how CDA could help. We were having the same problems not so long ago," Dr. Cowie explained. He said that Mr. Ajmearwala was missing three pieces to the copper motor rotor puzzle: a cover to prevent oxidation, a new high-temperature die material and an induction furnace to speed melting.
"After a few trials and with kind help of CDA, we have succeeded in our project," Mr. Ajmearwala explained.
Currently, Mr. Ajmearwala produces 1-horsepower cast copper rotors, having an outside diameter (O.D.) of 5.5" (140 mm ) and measuring 5.9" (150 mm) in length. While he's confident he will be able to cast rotors of up to 15 horsepower with the help of an induction furnace, his new challenge involves an entirely new application for die-cast copper rotors - submersible pumps. "Almost all pump manufacturers are seeking die-cast copper rotors. Therefore, rotors for submersible pumps are something we are very interested in," he explained. However, while submersible pumps are generally only 3.34" (85 mm) in diameter, they can be up to 15.7" (400 mm) in length, far longer that anything Perfect Die Cast is producing today. Nonetheless, Mr. Ajmearwala is in the process of running some tests. 0
Mr. Ajmearwala sees an expansion of his business using die-cast copper rotors, even beyond motors for pumps. "There is a big market to replace current aluminum rotors with copper in other motors for machines like looms, twisting machines and plastic molding machines. We are looking for that, too," he said. Mr. Ajmearwala can be contacted via email at perfactdiecast@hotmail.com or through writing to: Perfect Die Cast, c/o Metal Crafts, 7/1522, Dr. Ambadker Road, Surat.395003 Gujarat, INDIA. His phone number is 91-261-7410144 & 7427944.