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Yaskawa EV Motor – New Wire Shape Eliminates Rare-Earth Magnets

Rare-Earth Neodymium Magnets - None of Which are Found in Yaskawa's New EV Motor
Rare-Earth Neodymium Magnets – None of Which are Found in Yaskawa’s New EV Motor

Some of the world’s most powerful magnets, not including electromagnets, are made from the rare-earth metals neodymium, samarium, or yttrium. As a result, rare-earth magnets are expensive, while magnets made of iron, ferrite magnets, are cheaper, but not nearly as strong.

Electric motors only function because of magnetism, and can be made up of arrangements of electromagnets and permanent magnets. By replacing ferrite magnets with neodymium magnets, an electric motor bound for an electric vehicle [EV] can be made smaller and lighter, weight being an important consideration in such an application.

In order to reduce dependency on rare-earth magnets, and therefore costs, Yaskawa Electric set out to produce an EV motor with a ferrite magnet core. The problem with the ferrite magnet, though, was strength, so Yaskawa had some work ahead of it to maximize the power output of the weaker core. First, the shape of the magnet had to be optimized to improve torque output.

Then, Yawaska made a change to the coil wiring itself. Instead of using the standard round-cross-section wiring, Yawaska switched to a rectangular-cross-sectioned wire, which stacks better on the rotor and stator. This resulted in a 30% increase in the number of windings they could put in the same space, increasing the power output over the standard round wire motor.

The resulting EV motor, about the same size as currently found in EVs and hybrids, weighs about 132 pounds and maxes out at 12,000 RPM. With a maximum power output of 80kW and 147 hp at zero rpm, the new motor fits in the range of what’s required for a small EV or hybrid vehicle.

By eliminating rare-earth magnets and combining new processing and optimization, the result is a cheaper motor, which would help to reduce costs of EVs and hybrids alike. Reducing costs would certainly help marketing these high-technology vehicles and help them gain acceptance in such a difficult market.

UPDATE: Phantom Pasting Error Eliminated [First Paragraph]

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  1. wanderfire looks like you caught a rare and elusive phantom pasting. “Italian and Indian Research – Cheap and Safe Hydrogen Production” SHOULD have said “rare-earth magnets,” but I must have accidentally cross-pasted the title of something else I was working on.
    Sorry for the confusion.
    “There is no such thing as a fool-proof system. Someone will make a better fool, tomorrow.” Caught in my own quotation again!

  2. I don’t understand this sentence.  “As a result, Italian and Indian Research – Cheap and Safe Hydrogen Production are expensive, while magnets made of iron, ferrite magnets, are cheaper, but not nearly as strong.”  What exactly are you saying is expensive?

  3. thanx for this ben-years ago hexagon cross section wires were tested for power relays.with the same improvements,you describe for square sections
    unless some improvements in ferrite magnets have also escaped my scattered attention-heat destroys iron magnetic feilds,at about 120*C
    since heat also destroys conductivity of the wireing,this needn’t be of orwelming concern,as long as cooling provisions for the motor are-more than adequate.
    Tesla developed a heat generator,that produced an induced pulse of voltage,as steam heated a iron magnet just above the threshold.As it cooled,and the magnetic feild restored,the process was repeated.While vetting this you may want to give his steel conductive band homo polar motor generator a check-200rpm,11 volts max and gobs of torque-and the first development of a conducting brush design yet to be exeeded-still used today.


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