Magnets aren’t US anymore

The permanent magnetic is a quiet, unobtrusive work horse in so many applications that it, like many things that are mechatronics related, is mind bogglingly (is that a word?) pervasive.  Magnets are the key material technology to enable high efficiency and power dense electric motors.  And electric motors are everywhere.

The particular magentic material that has enabled the CD, DVD, Hard Disk Drive, high performance speakers, magnetic resonance imaging and many other technical wonders, is Neodymium Iron Boron.  Based on General Motors research on magnet materials (in the 1980’s), scientists found a particular molecule of these materials which exhibited extremely high magnetic strength.  And, of course, one of the immediate benefits would be reducing the size of starter motors in cars by 30% and the weight of the motors by even more.  Great stuff!

But making the molecule wasn’t exactly a picnic.  Alloying was easy, but it turned out you had to cool the material down suddenly in order to get just the right molecule to form in a powder and then sinter and magnetize the result.  A whole new process had to be developed, called spin casting, to cool the material quickly enough to generate high quality raw material for NeFeB magnets.   I’m sure there are a lot more technical details, but I don’t remember much from my tour of the GM Magnequench facility in Indiana.  It’s been several years.

NeFeB alloy has been dramatically improved and as demand has increased, fortunately, the price has dropped from the extremely high levels during it’s introduction.  As prices have declined it is estimated that 16,571 tons of Neodymium were used in magnet making in 2009 and 24,635 tons will be used by the year 2014.  That’s an increase of 48% in five years.  That’s huge.

The reason for all the increase is the fact that NeFeB magnets make really efficient motors.  So the new generation of appliance motors and air conditioning compressort that include NeFeB magnetics to increase the flux of the rotor combined with electric and hybrid car motors are driving demand more more magnets.  And now some emerging technology in the wind power marketplace, direct drive generators, will require many tons of additional material.

But what about our friends at GM Magnequench?  They’re gone!  The great future, full of potential for a US manufacturing company, lost to the sale of the company and closing the manufacturing facility.  GM sold the company to New Materials Technology in Toronto which is owned by China.  But the new owners couldn’t run the US factory at a profit.  Even at $20/hour for labor.  All the manufacturing jobs, gone.

There is currently no NeFeB magnet manufacturing in the US.  Which is kind of crazy when you think of all the applications we have for the stuff.  Even worse is the fact that a lot of advanced military hardware is dependent upon the magnets for guidance motors on missiles and a host of other applications.  And according to one source China now owns 97% of the world’s Rare Earth Elements sources.    Which is why there are now hundreds of companies in China selling magnets.

On the positive side, this has lead to overall declining prices for these magnets.  But will that continue to be the case?  The Chinese government is expecting to decrease their exports of magnets by 34% next year.  This could spell trouble for many companies.

But there is hope. The USGS has reported that the Mountain Pass Mine in Southern California is one of the largest and richest deposits of Rare Earths, including Neodymium, in the world.  And Molycorp is ramping up to fill the gap with new mining and manufacturing capacity.  Go get ‘em guys! Free enterprise at work.

Big Wind Machines

Recently I had occaision to discuss the merits of wind power with a colleague.  In particular there is a controversy between horizontal axis wind turbines, the giant propeller driven systems you see in advertisements, and vertical wind, which does not have much presence in the marketplace.  The premise is that horizontal systems can take advantage of the large swept area of the propeller blades to generate a great deal of force.  I’m not sure if this is supposed to imply that large swept areas intrinsically convert more kinetic energy from the wind into electricity.  And it is easy to conclude that this is the benefit of horizontal wind turbines.

Except that there is a fundamental mechatronic system at work.  The large propeller turns at low speeds, typically around 18 rpm on average, and there is a massive gearbox that is used to increase the speed of the output to turn a generator at high speed, which is typically where generators are most efficient.  The gear increaser has the effect of also increasing the amount of torque required at the input (propeller) by the gear ratio.  So if the gear increase is 100:1, then the propeller must be size 100 times larger in swept area in order to produce the needed torque to turn the generator.

This actually gets a bit worse since the mass, and it is very substantial, of the gear box itself represnts inertia that is resisting the turning of the blades.  And there is a generator rotor at the end of the gearbox whose mass (massive mass) is now resisting the turning of the propeller by the square of the ratio.  So if the ratio is 100:1, the inertia is increased by 10,000 times.  Even magnetic drag, or the residual attraction of the rotor to the stator, will get amplified in the same fashion, making it a significant force to contend with.

Add to this situaion a list of systems losses for overall fricitional loss of the bearings and gearbox, parasitic losses for steering and blade pitch adjustments.   Efficiency losses due to long distance transmission of power, that is a by-product of the remote sites that have favorable wind conditions.  It’s a pretty difficult situation to engineer.  And they keep proposing to build them bigger and bigger, hoping that the scale effect will overcome the problems.

All of the vertical wind systems I have seen so far are much smaller due to the fact that smaller rotors can turn at higher speed and power electric generators directly.  The flax axial generator is very popular in do-it-yourself designs that people are experimenting with in their back yards.

But vertical wind can also scale up.  And there are a few companies doing it.  With convertional wind power costing $2/watt, vertical systems could bring that price down very quickly and allow systems that can be installed close to the point of use or in offshore arrays where generation takes place almost 100% of the time.  Unlike the average 31% on the large land based systems.

Now that’s progress, 300% increase in energy generation at lower cost.  Hope it comes to market soon.

Car Wars?

For seventy years what was good for Detroit was good for America.  The major auto makers could sell as many cars as they could make.  And Americans were enthusiastic about the freedom offered by relatively inexpensive personal transportation.  Since Henry Ford’s introduction of the mass produced Model T and John D. Rockefeller’s agreement to provide gasoline at cheap prices, the gasoline powered automobile has dominated the landscape. Great fortunes were made.  And lost.

The steam and electric cars of the early 20th century were swept away by the low cost gasoline powered Model T.  The true cost of technology in action.

Since the first oil embargo in the 1970’s (under the Carter administration) energy costs have been fluctuating.  And how have the automaker’s responded?  With the same vehicles they have been making for decades.  American car makers have had problems with low cost, high mileage cars for a long time.

As people have progressively become more environmentally aware, the by-products of combustion have become an attribute that people would like to change in large measure.  This could come about by increased efficiency or alternative technology.  In the last few years, all the hybrid vehicles sold in the US have been imports.  The current sales rate puts imported hybrids at 300,000 vehicles a year in the US.  That’s a lot of cars we didn’t build.

The Environmental Protection Agency has been trying to get American automakers to improve vehicle efficiency for 30 years or more.  The response from Detroit has always been reluctant.  Change will be costly and take a long time.  And even when mileage target agreements were made, they never seem to be met.

In most businesses, when you stop meeting the customer’s needs, you stop selling product.   That’s exactly what has happened.  American car buying has dropped from 13 million units/year to 8 million units a year.  Big change.  Regardless if you blame it on the car companies or economic conditions, or both.  And a lot of harmful consequences to the economy since cars consume more steel, glass, carpet and just about anything you can think of, than any other sector of the economy.

Foreign manufacturers have settled into the US market and established themselves taking a share of market away from Detroit.  I didn’t hear anyone calling for reorganization of the industry during the last two decades while Japan set up shop on our soil.

So it seems a little strange to have government, which doesn’t actually know how to produce anything, dictating how the automakers need to produce cars.  One aspect that concerns me about the current plan from Washington is that it is based on projections of sales volumes ‘returning to normal’.  At sales volumes of 12 to 13 million the current plan will restore the automakers to financial health.   Does anyone believe that the American car makers can sell that many cars per year any time soon?

Electric Vehicles and Electric Motors

A friend of mine finally got delivery of a Tesla Roadster.  This prompted discussion of the drive train and the fact that Tesla has had to go from two speed transmissions which were failing to a transmissionless drive train.  The ultimate mechatronic challenge, the electric car, is also a challenger in terms of the precise  application of electric motor technology.

But it has to be said that the motor and drive solution for the electric car is not where the problem has to be solved.  Any motor can be made to run an electric car.  What is critical is how you apply it.  The starting conditions require high torque at low speed and the running conditions require low torque at high speed.  So, typically, what looks like a small 5 to 15 horsepower running requirement at full speed, becomes a 150 horsepower starting requirement depending on how quickly you would like to start.  If you want to keep up with a Corvette, it uses 450 HP to start.

And this produces a lot of confusion.  Why not use at 2 speed transmission to help the situation.  Fine, but the ones that are available can’t handle the dynamic response of the electric motor.

Can electronics help this situation?  Interestingly, yes.  There is a control algorithm generally called vector control which allows you to manage the rotor torque and stator torque separately.  By varying the phase angle between the two, like advancing and retarding the timing of a mechanical distributor cap on an internal combustion engine, you get different speed torque curves out of the motor.  COOL!  Is there any downside to this?

Yes.  You need more current to produce more torque.  That doesn’t change.  So you have to be able to supply the current, and you have to be able to manage the heat.  The heat is transitory since you only need the high current during starting, but it is best to have sophisticated software running to keep track of the RMS temperature of the motor.  Lower operating temperatures mean longer life and reduced risk of demagnetizing the motor.

So, yes, you can run an electric car with a garden variety AC motor, and with good electronics, you can make it run fairly efficiently.  With higher efficiency motors, the benefit is increased driving range from a given power source.  High efficiency motors are frequently smaller and lighter weigh, but a weight savings in the motor of 50 or even 100 pounds is not that big a factor in the driving range when the curb weight of the vehicle is 3000 pounds.

Basically, its F=ma.  If you can reduce the mass of the vehicle, you reduce the battery payload required to power the car.  Aluminum space frames, like on the Prowler, have been studied by the car industry and can reduce curb weight by 400 pounds and reduce cost by 10% at the same time.  We need to bring all the mechatronic leverage to the situation that we can, if we are going to make electric cars that make sense.  Before its too late for Detroit.

Peak versus Continuous Power

Another aspect of applying electric motors to power mechanical systems is the relationship between peak power and continuous power.  In mechanical systems the forces required to start a load may have no relationship to the power required to keep the system running.  Further, the  ideal demand for mechanical power may occur at a speed that has no relationship to the electric motor speed.

AC motors operate at fixed speeds unless they are controlled by a frequency inverter.  So matching the electric motor to the demand for mechanical power requires some electrical sophistication.  The most important factor in most energy conservation applications for inverters and AC motors is creating the right control strategy to match the demand for power to the to electric motor.  (we’ve done some articles on this subject so I won’t repeat the comments here.

Interestingly, the same problem with continuous and intermittent ratings show up in a lot of situations.   In the alternative energy arena, many systems are specified based on the peak power available from the equipment.  Most of the photovoltaic systems being installed are flat panels which only reach maximum output for a couple of hours a day when the sun is perpendicular to the solar panels.  During the rest of the daylight hours the photovoltaic panels put out considerably less power.  So there’s a big “disconnect” between the cost of the technology and the value it produces.

Photovoltaic pricing is still very expensive.  Residential installations that can produce enough power to take your home off the grid currently cost about $35,000 including installation.  Most state programs and federal tax rebates will pay for about half the cost.  But even at $15 to $20 thousand dollars, it costs more than most people can afford.

In the wind energy arena, the same rating problem exists. Wind power systems are rated at their maximum output.  But that output can only be achieved a certain number of hours out of the year when the wind is blowing in the right speed range.  Not too fast, because it’s hard for the power conversion systems to function, and not too slow or the wind won’t turn the generator.

So these million dollar machines must harvest the wind enough hours to make a profit.  This means it’s all about “location, location, location”.  The game is to find a location where there is enough wind for enough hours to generate electricity and a profit.  And that’s not easy, and it’s not cheap.  Locations that are suitable, like Altamont Pass in California, are remote and hard to get to.  This make installation more expensive and losses from sending the electricity long distances, less efficient.

In general the difference in peak versus continuous rating wouldn’t bother me so much, but it’s systematic in the alternative energy community.  It suggests a bit of misrepresentation as if to create a greater perception of value, when in fact, the systems being built take 8 years before they break even.

We can do better.

Manufacturers Take Note: Tax Deductions Going Green

High energy costs, an unprecedented level of government mandates for green building, heightened demand for green construction, and improvements and better pricing for environmentally sustainable materials have many building owners, architects, and facility managers considering significant updates to save cash. Sec. 179D of the IRS Code provides a significant deduction for the cost of energy-efficient improvements to commercial property.

With an estimated 4.5 million existing commercial properties in the U.S. and with 14 percent of U.S. cities with populations of at least 50,000 having mandated green standards for new commercial buildings and dozens more poised to follow, the 179D tax deduction could help mitigate the average 3-7 percent cost difference in building green.

Source: BusinessWire

The Greening of Lean Manufacturing

McClarin Plastics has coordinated a cooperative lean certification session for their employees, customers, and suppliers. “Each segment of the supply chain must understand the others’ needs. One kink in the chain can throw off the entire process causing waste and expense as well as excessive use of energy and raw materials,” says Roger Kipp, vice president of marketing and engineering for McClarin Plastics in Hanover, PA. “This will bring everyone involved in a related supply chain together to learn how their performance affects others. The positive bottom line impact from the resulting relationships and understanding could be huge.”

According to a study commissioned by the U.S. Environmental Protection Agency, suppliers in lean supply chains which deliver a component in the right quantity at the right time, share the benefits of reduced cost and waste reduction as well as a higher quality part. Further, James P. Womack, Daniel T. Jones, and Daniel Roos report in their book, The Machine that Changed the World, that many companies can only lean their operation by 25-30% if suppliers and customer firms are not similarly leaned.

Source: ThomasNet

Green Maufacturing

In the past, we engineers were charged with considerations such as Design for Manufacturing, Design for Assembly, cost targets, production targets, margin targets, tooling considerations, lead-time and other factors. Now, the new consideration is Design for Disassembly, sometimes referred to as Design for Destruction.  Just as manufacturing or assembling is a process to be optimized, disassembly or destruction of products to be recycled is a relatively new process and needs to be optimized. Read more