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Seventy participants from seven different countries attended the first copper motor rotor demonstration meeting in Denver, Colorado, January 29. Dr. John Cowie, CDA vice president of strip, sheet and plate and program manager of the project, said the meeting "marked an important step toward commercialization of this exciting new technology."
A wide spectrum of industries and businesses were represented - from motor manufacturers to research and development organizations and from academicians to die casters. All were given a comprehensive overview of the project and were able to view actual rotor casting.
The U.S. Department of Energy (DOE), the Copper Development Association Inc. (CDA), and research labs, Formcast and Trex Enterprises (formerly Thermotrex), sponsored the demonstration. "DOE asked CDA to hold the event because the technology is on the verge of commercialization. We needed to maximize exposure through a large meeting," explained Cowie.
Following a welcome address from CDA president and CEO, Andy Kireta, Sr., Scott Hutchins of DOE explained the government's involvement in the program.
Dr. Dale Peters, a consultant to CDA and former manager of the copper motor rotor project, reviewed the project's history and current objectives. He detailed the project from an engineering perspective by explaining the limitations inherent in die casting copper.
| Rotor Losses | 40% |
|---|---|
| Total Losses | 23% |
| Temperature Rise | 41% |
| Efficiency | +1.6% 90.9% vs. 92.5% |
| Stator windings and iron core were modified from standard motor design to gain best possible results. | |
| The data in Figure 1 illustrates the improvements achieved when a motor is designed specifically to use copper rotors. | |
Dr. Cowie described the trials performed by the copper motor rotor team that led to the success of the project thus far. Dr. Edwin Brush, a consultant to CDA from BBF & Associates, spoke more specifically about the science of die-casting copper rotors. Darryl Van Son, also a CDA consultant, detailed the testing procedures and revealed the results of tests performed by four different manufacturers, who all found a marked increase in motor efficiency using the copper rotor. (See Figures 1 and 2.) CDA consultant and die designer, Dr. Ruedi Beck of DieTec Ruedi Beck GmbH detailed the die requirements for casting of copper, such as venting, speed of fill and pressure requirements.
Cowie said the highlight of the event was the demonstration of actual castings at Formcast. Attendees broke out into four groups to ensure a close-up look at the process. "Judging from their reactions," Cowie said, "the demonstration convinced them that casting copper rotors economically was now a reality."
| hp | kW | Poles | Al | Cu | Difference | Reduction |
|---|---|---|---|---|---|---|
| 4 | 3 | 4 | 221 | 92 | 129 | -58% |
| 5 | 3.7 | 4 | - | - | - | -38% |
| 15 | 11 | 4 | 262 | 157 | 104 | -40% |
| 25 | 19 | 4 | 410 | 292 | 118 | -40% |
| Figure 2 demonstrates the reduction in I 2R energy losses achieved by switching from aluminum to copper conductor bars. | ||||||
"The event was extremely successful," Cowie summarized. "There was a lot of interaction among the participants. Through this type of interaction, the activity of the copper motor rotor project will devolve from CDA to individual manufacturers. We're beginning to see the first of the manufacturers bringing this technology in-house."
As the project moves further toward commercialization, according to Cowie, CDA will continue to promote the copper motor rotor, but scale back on research and development, since the problem of cracking has been solved. The focus of the project will now be on demonstrations for individual factories.