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.
To me, the message here is that innovation isn't just about coming up with the next new technology idea, but also being creative enough to see there can be novel approaches to old problems. The rare earth shortages are likely to continue for some time. This is a great example of deft engineering and being able to shift gears to another way of problem solving when something stands in your way.
The interesting thing to me about this work is that NovaTorque initially started out working with rare-Earth magnets and only tried the technology on ferrite magnets after rare-Earth pricing got out of hand. whatthat means is that in a few years, when new sources come online and the price of rare-Earth materials drops, NovaTorque can take what they've learned and begin making rare-Earth versions of their design, which could create uber-high-performance motorseven more compact and conventional rare-Earth versions.
Kristin, That is a great point. In solving a material problem in the near term you set yourself up for even more effeciencies when that material comes down in price.
I agree, Beth. This is a great story of innovation in the face of economic necessity -- a great example of the old saying, "It's not what you have, it's what you do with it."
Beth, there are enough rare earth metals are available in China. They are possessing about 85% of the total availability. If China is willing to open up their market for international customers/companies, most of the problem may get resolved.
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.
I know many folks are poking fun at the idea of a push to asteroid mining, but as our high-tech gadgets require more and more high-tech materials that are becoming more and more scarce, looking off-world for new supplies sounds like a logical next step. It also beats the heck out of our entire technical workforce generating new mobile apps for their entire career...
Interesting idea, William. This is the basis of the Alien movie series, that space travel will essentially be based on mining. That may be the case. Yet, given our gains in creating sophisticated robot technology, the mining missions may not involve humans.
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?
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.
@Rob- This reminds me of silver mines in the Cerro Gordo area of California, near Death Valley. The silver boom was the catalyst for LA's growth in the late 1800's. For awhile the ore was shipped to LA and then processed. Of course they soon realized almost all the weight they were hauling was slag, so mills were built next to the mines.
So asteroids will be mined but the valuable materials will be extracted on site, enroute to Earth, or perhaps on the moon. Maybe the output is ingots which are shaped and coated to reenter the atmostphere. True there's a risk from stray ingots landing in the wrong place, but then again 400 ton aircraft loaded with billions of BTUs of fuel fly overhead every day!
Sounds like a Burt Rutan problem-solving exercise!
That makes sense, Kenish. Make the output from the mine pure and dense so you're not transporting any waste. I understand that's how port developed. If you added alcohol to wine, you could ship a richer product at the same weight.
I suspect that transporting tons of raw materials back to earth will be a lot more costly than transporting them from under the ocean -- unforeseen difficulties are sure to play an economic role there. Still, I agree with you that our taste for high-tech will one day make asteroid mining a reality.
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.
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.
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.
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.
Is that you,mom?
Government IS the source of all our problems. Their central planning and over regulation causes constant and severe problems. They can't be ignored, and more of us need to be ranting and not just sitting on our butts complaining about those who are concerned. Mom.
The problem is human beings. If you were to be objective, you'd see that as humans are social animals, government is inevitable as some sort of hierachy is always developed. Any argument that government is the source of all our problems is therefore simply invalid.
Also, what "over-regulation"? That argument can be ignored as it's a canard. The claim is a) not supported with any examples and (b) generally created from a very narrow economic definition, generally from a specific ideological perspective, that conveniently ignores externalities not considered improtant by the claimer.
So, the fact remains that REE are rare, China happens to be the major source, and trade agreements and policies have made it more difficult for the US to apply any leverage to coerce China to export them more freely. Therefore, the only valid alternative is to develop more efficient means for using electricity that reduces the need for these rare elements.
Sorry to be so smart alec. It just comes so naturally.
I know we are social animals, but it is about liberty. Liberty is everything, and it is the nature of government to try and capture all the power it can and limit the liberty of the people, ergo the "Patriot Act." That is why the Constitution is so important. It puts limits on government and leaves the power to the states. The Fed is where the problems are.
But enough of that. About the Rare Earths. I spoke from an article I read recently, so I was referring to that. I cannot remember the source, but I accepted it. I'm easy that way. I know China is an awesome source for these, but not the only source. Right now it is the main supplier, and thus they control the market. They control the market on a lot of things, politicians included. Oops, back to politics.
What do you mean by "liberty"? It's essentially a meaningless word as it means whatever anyone wants it to mean, ranging from implying that one can do whatever one wants without any consideration as to the consequences of those behaviors to behaviors constrained by ethics and morals. So, what do you mean? The constitution is interpretable, so while the constitution puts limits on government, it provides wide latitude for action in the general welfare and the constitution itself denies unconstrained libtery because it replaced the Articles of Confederation.
Also, it's not that China is an awesome source, but that it may have a greater concentration of REEs. So, their resources are their resources and while we have trade agreements, we must still deal with the fact that what is in their control is in their control and while the US has made the conscious decision to give away our technological knowledge and allow foreign mining interests access to our resources for essentially nothing, China may not do so.
As for that article you linked to, it provides absolutely no details about its claims, such as what do they mean by "not rare", and any support as to whether they are more common than Cu. Start here: "Rare Earth Elements—Critical Resources for High Technology".
Thanks for your comments--sorry for the delayed reply. The remarks about "rare earth elements" being something of a misnomer are correct. You can find more detail in a U.S. government report at http://tinyurl.com/bqjudr8. "The more abundant REE are each similar in crustal concentration to commonplace industrial metals such as chromium, nickel, copper, zinc, molybdenum, tin, tungsten, or lead (fig. 4). Even the two least abundant REE (Tm, Lu) are nearly 200 times more common than gold..."
The issue is that the elements are typically found bound with other materials, so they require effort to extract. The dynamic going on with China is that they mine REE ores as a byproduct of another mining operation -- they're basically turning scrap into revenue. This is partly why they were able to drop prices.
As far as alternative sources go, the Mountain Pass mine actually features REEs In much higher concentrations and Chinese sources, at least for some of the main REEs. This may help the mine to be more cost competitive as they get things up and running. The bottom line is that the cost is coming down but will probably never get anywhere near as low as they were in the heyday. That said, the ability of engineers to design around the problem is part of what the and driving down demand and causing the speculators to release their inventory, hence driving down the overall cost. There are enough design options around that I think we'll be okay.
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.
The rare earths problem will take care of itself over the next few years. Now that prices have gone up -- due to China's rationing -- it is now affordable to mine rare earths here and in Australia. Soon Afghanistan will come online as well.
There is and will continue to be a high cost for neodymium and dysprosium materials because of the negative environmental impact of mining, with the escalating use of electric vehicles and wind turbines, and yes, with speculation. Mines are reopening because of the RE high cost but will they stay open if the high costs diminish? Some countries are already making their move: http://www.raremetalblog.com/2012/02/cerium-neodymium-and-dysprosium-prices-keep-tumbling-report.htm. And yes, there are certain kinds of electric machines without permanent magnets that have higher efficiency, torque density and power density with lower cost than permanent magnet electric machines.
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