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The copper rotor induction motor is a strong alternative to the permanent magnet motor for electric vehicle traction when comparing cost, performance and reliability, say automotive industry leaders in a new video released today by the Copper Alliance.

Video Link

The video features industry experts from Remy International, Inc., Fukuta Electric & Machinery Co., and AC Propulsion, all companies that have supplied the copper rotor induction motor for electric vehicle use.

Permanent magnet motors require rare earth metals, while copper rotor induction motors do not. This is significant as prices for rare earth metals have increased more than 400 percent in the last two years as of April 2012, according to

As a result of cost increases, suppliers are now looking for alternatives to rare earth metals, says Wally Rippel, chief technology officer and co-founder of AC Propulsion, located in San Dimas, Calif.
“We’re now in a situation in which getting the rare earth materials for the permanent magnet motors is becoming increasingly difficult, both due to supply and demand,” Rippel, says in the video.

OEMS are looking for alternatives

Fukuta Electric & Machinery Co. in Taiwan has collaborated with Tesla Motors on the development of a copper rotor induction motor for Tesla’s electric Roadster.
“Right now it appears that the future trend will be for electric vehicles to rely more on copper rotor motors,” Gordon Chang, Fukuta’s founder and general manager, says in the video. “We have seen that Tesla’s copper rotor motors haven’t had any problems during the nearly four years that they have been out on the market. This is sufficient proof that this product is able to pass the so-called four-year field test.”

OEMs and others interested in learning more can contact the Copper Development Association (CDA) for connections to manufacturers who have experience building copper rotor induction motors, says Bob Weed, the CDA’s vice president OEM

“It’s a perfect opportunity for the CDA to collaborate with engineers and designers, and ultimately, their consumers, as we show how copper rotor induction motor technology will benefit the electric vehicle industry,” Weed says.

Copper Induction Motors vs. Permanent Magnet Motors for EVs

Copper induction motors have comparable torque and efficiency to permanent magnet motors, along with a rugged, durable design. There are other advantages:

• Copper rotors don’t have a drag loss due to reluctance while running and their efficiency remains high during high speed and low torque conditions. This makes them well suited for both pure electric and plug-in hybrid vehicles.

• Copper rotors provide an economic advantage over aluminum rotors. Although the raw material cost for aluminum may be less than copper, a motor with a cast copper rotor can be up to 25 percent smaller than an equivalent motor with an aluminum rotor, and so is less costly overall. The superior heat conduction of copper also contributes to cost savings.

• The use of die-cast copper rotors (a manufacturing technology that has been perfected over the last 10 years) provides an efficient, mass-production process.
Automotive Copper Facts to Consider*

• The average car produced in North America has 50–55 pounds of copper in it. In an electric car, that amount triples to 150–180 pounds.

• More than two-thirds of the copper will be found in the car’s wiring harness and electrical components.

• Copper has the highest conductivity of any metal that can be practically used for conveying electricity.

*Source: Copper Development Association

About the Copper Alliance
The Copper Alliance is a group of global copper associations led by the International Copper Association. The Copper Alliance mission is to defend and grow markets for copper, based on its superior technical performance and its contribution to a higher quality of life worldwide.

The Copper Development Association is a member of the Copper Alliance, representing North America.

About the International Copper Association

The International Copper Association increases awareness and the usage of copper by communicating the unique attributes that make this sustainable element an essential contributor to the formation of life, to advances in science and technology, and to a higher standard of living throughout the world. The ICA’s 43 members represent a majority of the world’s refined copper output and are among the largest copper producers, fabricators and wire and cable companies.

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