Hitachi unveils motor without 'rare earths'

Apr 11, 2012
Japanese high-tech firm Hitachi Wednesday unveiled an electric motor that does not use "rare earths", aiming to cut costs and reduce dependence on imports of the scarce minerals from China.

Japanese high-tech firm Hitachi Wednesday unveiled an electric motor that does not use "rare earths", aiming to cut costs and reduce dependence on imports of the scarce minerals from China.

The prototype 11 kilowatt motor does not use magnets containing rare earths and is expected to go into commercial production in 2014, the company said.

Hitachi started work on the project on 2008. Other Japanese firms, including automaker Toyota, have been working towards the same goal, spurred on by high prices of the minerals.

motors usually contain rare earth such as neodymium and dysprosium and are in increasing demand for the growing number of hybrid and electric vehicles.

Japan has been seeking to reduce its dependence on rare earths and to diversify sourcing to cut its reliance on China, which controls more than 90 percent of global supplies and has moved to restrict production and exports.

Japan was hit when China temporarily cut off exports in 2010 during a territorial row between Asia's two largest economies.

The United States, Japan and the European Union lodged a joint complaint with the in March, claiming China is unfairly benefiting its own industries by restricting exports of the sought-after minerals.

are used to make a wide range of high tech products, including powerful magnets, batteries, LED lights, electric cars, iPods, lasers, and missiles.

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User comments : 18

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sstritt
Apr 11, 2012
This comment has been removed by a moderator.
Fed_Up_With_Stupid
5 / 5 (3) Apr 11, 2012
I second that, what a frustrating article. Perhpas the answer is obvious to someone who is familiar with the details of how electric engines can put together but - I'm not such a person.
Sean_W
3 / 5 (2) Apr 11, 2012
The information that this is being developed is interesting and positive but yes, there is only the announcement of this fact. More content would be helpful.
Mike22
5 / 5 (3) Apr 11, 2012
The media get worse and worse, such articles missing the obvious content get more prevalent every day. Why bother?
Eikka
4.3 / 5 (6) Apr 11, 2012
This technology is probably the continuation of an earlier prototype by Hitachi: http://techon.nik.../161042/

How it works:

Coiled iron cores, which function as electromagnets when electric current is applied, rotate the permanent magnets that work as rotors and generate a turning force in the motor. In existing motors, magnetic steel sheets are used as iron cores and Nd-based magnets are used as rotors.

For the prototyped motor, amorphous metal was used for the iron cores, allowing the use of ferrite magnets as rotors. This is because the magnetic permeability of amorphous metal is ten times higher than that of magnetic steel sheets, while its energy loss is about 1/10 that of magnetic steel sheets. When the magnetic permeability of the iron cores is enhanced, a high magnetic flux density can be achieved even with a weak magnet.
Roland
3.7 / 5 (3) Apr 11, 2012
Rare earth magnets are used in the rotor of some motors. These motors are "brushless"..the rotor doesn't need current. For many years now, many motors are made with brushes that feed power to windings in the rotor via either sliprings or a commutator. So why is this article touting a technology that's been around since Tesla?
Pyle
5 / 5 (1) Apr 11, 2012
This would represent an important competitive advantage to Hitachi. You expect them to disclose their "secrets" to their competitors any earlier than necessary? No doubt all of the major automobile manufacturers will dissect the first motor they get their hands on and figure it out. Why would Hitachi provide details on something they gambled a bunch of money on to develop?
Eikka
3.7 / 5 (3) Apr 11, 2012
Put simply, a wire in a magnetic field will experience a force when a current is put through it - that's what makes the motor turn. Looping the wire around in a coil will see the same current acting multiple times in the same part of the field, so the force depends on the density of the field and the amount of current, and the number of loops in the coil.

The weaker the field, the more current and the more wire you need for the same force, and the less efficient the motor is due to electrical heating in the wire. Adding more loops in the coils also causes them to react slower to switching the current, which makes the motor slower. You can't afford to make the coils out of wire as thick as your finger either. That's why electric motors need strong rare-earth magnets to be small, light and efficient.

The problem is solved here by taking a weaker non-rare magnet and using a more advanced material (amorphous, or glassy metal) to better concentrate and direct the magnetic field.
Eikka
4 / 5 (4) Apr 11, 2012
So why is this article touting a technology that's been around since Tesla? -Roland


It isn't. It's still the same kind of permanent magnet brushless motor, which are superior in efficiency and power-to-weight ratio to brushed or induction motors, and more mechanically robust. They simply figured out how to do it with weaker permanent magnets that don't need neodymium.

Applying the same concept -with- neodymium magnets would allow for even better motors.

Why would Hitachi provide details on something they gambled a bunch of money on to develop? -Pyle


To get a patent on it. If you don't publish, you get no patent - that's the rules. It would be a financial suicide because it would be a matter of months before the Chinese would reverse-engineer the motor anyways.
TimUK
not rated yet Apr 11, 2012
Could this be a variant of the magnetless switched-reluctance motor?
Vendicar_Decarian
Apr 11, 2012
This comment has been removed by a moderator.
hikenboot
not rated yet Apr 11, 2012
This would so it seems solve a main barrier for Wind power...ie the inclusion of 350 pounds of rare earths. I hope they write something a little more technical about it.
Eikka
2.7 / 5 (3) Apr 11, 2012
This would so it seems solve a main barrier for Wind power...ie the inclusion of 350 pounds of rare earths. I hope they write something a little more technical about it.


They did, in 2007/2008 when Hitachi first made the prototype as a response to China's squeeze on the rare earths market at the time.

The main technical issue here is the manufacture of amorphous metal, because it is formed by rapidly cooling the alloy so it doesn't have time to form crystals. That means it has to be manufactured in thin sheets of only a few dozen microns thick, which then have to be stacked, shaped and tooled to suit the application at hand. That is difficult because the glassy metal is extremely hard and strong as well.

It seems that the problem of making these motors is in developing methods of manufacturing large enough metal cores for the magnetics, and forming them to the required shapes.
Fed_Up_With_Stupid
not rated yet Apr 11, 2012
@Eikka, Many thanks. That makes sense to me.
axemaster
not rated yet Apr 11, 2012
Moving away from rare earth magnets in electric motors is important to the future of our economy. One of the main factors standing in the way of all electric vehicles becoming commonplace is the huge quantity of rare earths it would take to build tens of millions of powerful electric motors.

Gogo Hitachi!
Burnerjack
not rated yet Apr 11, 2012
So, how much more efficient are these over rotating field induction motors?
Eikka
1 / 5 (1) Apr 12, 2012
So, how much more efficient are these over rotating field induction motors?


The better question is, where they are more efficient. At close to the designed nominal speed, an induction motor can be very close to 100% efficient as well.

The differences crop up when you go slower or faster, because the induction cage needs a current to be induced in it to work, and as the frequency of the drive current shifts up or down that process doesn't work as well anymore. Induction motors can't be made to work efficiently over such a wide range of speeds as PM-motors.

They don't have the same sort of zero-rpm torque available, because at that point you're pushing DC through the motor, which means there is no induction happening.
antialias_physorg
5 / 5 (1) Apr 12, 2012
Moving away from rare earth magnets in electric motors is important to the future of our economy.

Alternatively we could invest in technologies that extract rare earths from common soil. The stuff isn't exactly rare (as in "hard to find").It's actually pretty ubiquitous. Mostly it's just pretty diluted. Depending on the market value this can be economically feasible.
(Much like digging for gold using an enormous amount of hardware in the amazon is economically - though not ecologically - viable)

Rare earths are useful in a number of disciplines (not just electric motors/generators) - e.g. theer are applications in lighting and lasers which require them.
DaFranker
1 / 5 (1) Apr 12, 2012
Alternatively, someone in the Gray Rush (read: Graphene Grant Spam) might get lucky and stumble upon a stack configuration that mimics the desired properties of these rare earths, with production steps easy enough to engineer into a manufacturing line.

Then we'd just be golden (no pun here, move along).
Burnerjack
not rated yet Apr 12, 2012
@Eikka: Thanks for the clarification. Makes me think an induction motor using both vector variable speed drive and possible a variable ratio transmission such as dual cone drive could maybe provide a viable answer? I have had experience with vector drives and they are quite amazing in the control capabilities, albiet with some thermal losses as the SCRs switch on and off.