When neodymium-based magnets first hit the scene, they offered high flux but over a very limited temperature range. Modifications to the alloys, including the addition of dysprosium, ultimately yielded powerful, thermally robust magnets that enabled the development of motors with far greater torque density and thermal range than possible with traditional materials like aluminum nickel cobalt (AlNiCo) and ferroceramics.
Suddenly, engineers had the luxury of motors that were many times smaller and lighter than their conventional counterparts. At the same time, rare earth magnets remained cost-effective courtesy of Chinese suppliers, who soon dominated the market.
Figure 1: A speculation bubble has driven up the prices of rare earth elements in the past few years, while the cost of ferrite magnets has remained steady. (Source: NovaTorque)
In part four of this five-part design series, we look at how focusing flux in three dimensions allows ferrite-magnet motors to achieve performance and form factors competitive with rare earth designs. (Read part 1 here, part 2 here, and part 3 here.)
Everything was just dandy until around 2008, when speculators began hoarding materials, causing a supply contraction that drove up prices dramatically (see figure 1). What had been a viable industrial material became exorbitantly priced. The question changed from, "What can we do with rare earth magnets?" to "What can we do without them?"
The answer, according to NovaTorque Inc., is "plenty." They developed an axial motor design that focuses flux in three dimensions, rather than the two dimensions of conventional radial designs. The result is an economical ferrite-magnet motor that delivers torque and efficiency comparable to that of rare earth versions, in a similar frame size.
Radial air-gap permanent-magnet motors consist of a radially symmetric rotor nested in a cylindrical stator, with an air gap between the two. The rotor incorporates permanent magnets, either on the surface or the interior. The stator features electromagnets consisting of copper windings energized in a specific sequence by the drive to form alternating flux patterns. Both rotor magnets and stator windings are aligned with the z-axis of the motor, which causes the flux interaction -- and, hence, force exerted on the rotor -- to take place in two dimensions. When the windings are energized, the stator flux Φs interacts with the flux ΦR of the rotor magnets to exert a force on the rotor, causing it to turn.
The Chinese have been appropriating our technology with our full approval (remember IBM selling Lenovo their PC business?) due in large part to our policies developed to increase profits for corporations. We're our own worst enemy, the Chinese simply take advantage of our lack of foresight and greed. Also, our colleges make money catering to foreign students and I doubt that they'd not send lobbyists to Congress if there were any such attempt to send Chinese students home.
The fact is that REE in China are the property of the Chinese, and as they are their resource, they have a good argument as to controlling their export and we chose to send our technology to China because it brought a few well connected people more wealth. Perhaps we'd have more trade leverage had we not given China so much in the first place.
Maybe it's time to re-engineer our society to be far more efficient such that we don't require REE and conventional magnets can produce what we need. Oh, and reconsider our trade and business policies such that they don't benefit only a few. As far as I'm concerned this is all about sustainability.
I can't speak for Warren, but in an earlier post, I mentioned that there are about 110,000 or more Chinese students here at any given time taking our technology to China. It would be fair to send these students home until China opens up thier rare earth markets again.
Good point, ChasChas. I would imagine a craft could be build in orbit, much like the space station was. Then rockets would only be necessary to ferry passengers back and forth to the craft. Getting the payload from the craft down to earth could be tricky.
Unless the speculator can take delivery of teh materials in question, I think that he cannot 'hoard' materials, but will predict the future pirce of an item.
Now the increase in cost to us (the USA) recently may really indicate the 'real' devaluation of the Dollar vs. the Yuan.
Speculators do not stabilize prices, they create bubbles. Markets stabilize prices only when those bidding on the commodity have an actual stake in the commodity and not merely whether others will pay more for the commodity later than they did.
Sorry but RE motors are not close to many times smaller than other types. They won't be replaced by ferrite magnets but by far better tech like Telsa's and the EV-1's motors that use no RE and smaller than a similar RE motor. No?
So much hype and little substance here.
The article on UC's is far worse, just pure hype by the manufacturer. I can't wait to see his response. It should be enlightening for all of us.
Our missing link to successful space mining is that we have no space drive like all the science fiction crafts and what has been observed in "UFO's". We need something to replace the rocket to break earth's gravity before real economic feasibility is here.
Where are we at on the carbon nanotube ribbon hooked to a geosynchronous satellite?
As a user of rare-earth magnets I hear there are large quantities of the resources necessary here in the USA but for the cost of getting it out of the earth. I guess the "rare" part is the permits, etc.
China broke international agreements in withholding this material from the world. I think it is a brilliant maneuver to raise prices. Saudi Arabia, et al, do it with oil. I do it with my vast mental capacity and my stunning good looks. So, the solution is an engineering one. How can we get around China? We got around the buggy whip cartel with the automobile. We can find ways to extract it from our own soil effectively, safely, and cleanly (unless the government has another hidden agenda in agreements with China). Or we can find substitutes. Maybe there is a substance we can use like "I Can't Believe It's Not Neodymium!"
I don't know if I buy the "hoarding" excuse. Speculators tend to stabilize prices. I think dark-side politics are at play, Mr. Watson.
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