In the meantime, however, I wanted to mention that I have now uploaded a PDF file that contains the slides from my talk, titled “Recent Developments in Permanent Magnet Gear Systems & Machines” – click the aforementioned link to download it.

The primary purpose of any gearing system is to convert between speed and torque. Typically using a rotating input power source, we want to either increase or decrease the speed in the output shaft, via a converse decrease or increase in torque – and vice versa. Typical examples of such systems are automobiles [where we want to convert the high speed of the rotary crank shaft in the internal combustion engine to a relatively high torque at the wheels] and wind turbines [where we want to convert the high torque but relatively slow movement of the turbine blades, into the high speed required by typical generators]. This conversion between speed and torque is actually a form of power conversion from one part of the system to another.

A key drawback of using mechanical systems for such conversion is that there is friction, wear and tear. Only a few gear teeth mesh at any one time, the rated torque values are by necessity lower than peak torque because of fatigure issues, and there is a lot of lubrication and maintenance required. In addition, failures of such devices tend to be catastrophic – when a mechanical gearbox fails – it fails!

Enter the magnetic gearing system. With no contact between elements, there is no friction to cause wear and tear. Multiple magnetic poles are engaged and thus the systems are highly efficient at converting power. Input and output shafts can be isolated too, which presents additional options for the mechanical designer.

Going a step further – fully integrating magnetic gears with electrical machines such as motors and generators, results in superior, best-in-class torque densities for any electromechanical / electromagnetic power conversion system. This result makes magnetic gearing a very promising technology for a variety of devices, including the possibility of highly compact, high powered traction motors for in-wheel drives for vehicles. Torque densities of up to 140 kNm / m^3 have been achieved, with the ability to produce up to 35 kW of power in a single in-wheel traction motor.

My presentation in Florida covered the recent developments in this area, including low gear ration and high gear ration systems, the history of research into magnetic gears, as well as some potential applications. These are early days for such systems, but I think it’s only a matter of time before they are widely deployed.

You can download a copy of the paper from here.

The research was conducted at IBM’S Zurich Research Labs in Switzerland, in conjunction with Fujifilm. What’s interesting is that just as hard disk drive media has gone from longitudinal recording, where the data bits are stored lengthwise, to perpendicular, where the bits are stored perpendicular to the surface – the same concept has been applied here to magnetic tape. The result in both cases is a significant increase in areal density of storage. Thinner tape can also be used with this technique, which means more tape can be stored on a spool. the particles used are made from barium ferrite – more commonly seen in everyday ceramic ferrite magnets.

However, the new tape technology created a problem:

Increasing the density of data that can be stored on a tape makes it more difficult to reliably read information. This is already a problem because of electromagnetic interference and because the heads themselves will retain a certain amount of residual magnetism from readings. To overcome this, the IBM group developed new signal processing algorithms that simultaneously process data and predict the effect that electromagnetic noise will have on subsequent readings.

Since tape backups are still a mainstay of any self-respecting IT department these days, this new development will hopefully make their lives easier. And let’s face it – if your IT department is happy – YOU’RE happy, and vice-versa, if you know what I mean….

The folks at IBM say that it might be as long as five years before the tape material is ready for prime time, but even so, this new development may well extend the lifespan of this data storage technology for many years to come.

The device is actually an upgrade to an existing electromagnet, and uses a special coil design called a Bitter solenoid, in order to generate the intense magnetic field. This design, first invented by Prof. Francis Bitter while working at MIT prior to World War Two, consists of stacks of copper plates, instead of wire coils, in order to carry the massive currents that are required for the electromagnet. The working inner bore of the new magnet is approximately 32 mm [1.25 inches] in diameter.

The increment from 35 T to 36 T came from creating a new arrangement of the copper plates in the Bitter solenoid. The researchers at the NHMFL plan to apply this new arrangement and upgrade the rest of the electromagnets at the lab, in order to increase the overall magnetic output of each. As an added bonus, according to laboratory:

[t]his cost-neutral modification means a higher magnetic field can be created using the same amount of power, 20 megawatts. By comparison, the magnet at the Grenoble High Magnetic Field Laboratory achieves its 35 tesla using 22.5 megawatts of power.

Frog levitating in a 16 T resistive electromagnet (image courtesy of High Field Magnet Laboratory, Radboud University Nijmegen 2005)

To put this into context, 20 megawatts of electricity is enough electricity to power around 6,000-7,000 average American homes. A 2.5 MW saving in electricity [equivalent to the power produced by a commercial scale wind turbine these days], for the same magnetic output, is therefore pretty significant.  During a visit to the NHMFL a few years ago, I was told that the laboratory is required to give plenty of notice to the local municipality in Tallahassee before switching on their electromagnets, because of the massive current draw on the local grid that they cause.

It was in a very high field electromagnet of this type, that the famous picture of the floating frog shown here, was taken some years ago. The strong diamagnetic effect of the electromagnet, on the water molecules in the frog’s body, is enough to counter the effects of gravity.  When not levitating amphibians and other objects, researchers use these types of very strong electromagnets for physics and materials science research.

The use of algae as a potential source of fuels is nothing new within the world of renewable energy. As Siemens says:

Algae are a valuable source of raw material. For millions of years throughout the history of the world, they have transformed CO2 into valuable organic molecules. Some species specialized in the production of fatty acids and lipids. Their fossilized remains from the dawn of time are the foundation for the petroleum and natural gas extracted today. Algae continue to harbor enormous potential today as suppliers of biomass, biogas, or biodiesel. They are also easy to cultivate. They don’t need anything more than CO2 and water, and preferably wastewater at that because of the nutrients it contains.

The problem is that while it is relatively easy to grow algae, harvesting it is a real pain. Within a liter of water, only a few grams of algae grows at a time, and so the water has to be filterd and drained, which is time consuming.

The solution, according to Siemen’s Manfred Ruehrig, is to add a fine powder of magnetite – iron oxide – into the water.  The algae latch onto the magnetite and, after stirring, the algae-magnetite combination can be easily removed by using an external permanent magnet. Although this has only been done in the laboratory so far, results have been promising, and could lead to the scaling up of the process, using similar processing equipment to that used for industrial magnetic separation. The magnetite would be re-used after separating it from the algae.

According to Siemens, the process would result in less water loss, and thus it could be used for drying in drier areas.

The use of magnetic particles in this way is not dissimilar to well-establish biomagnetic separation techniques used in the medical sector, to separate blood cells, DNA and other biological entities, using combinations of chemically-active magnetic nanoparticles, and powerful magnetic fields generated by specially-shaped magnetic configurations.

The tool was developed by the magnetics engineering group at Dexter, specifically by a team led by my colleague Chris Ras, Dexter’s Product Development Manager, and with the support of the U.S. Department of Energy’s National Energy Technology Laboratory (NETL).  The tool, shown in Figure 1, is approximately 67 inches (170 cm)  long and provides over 200 watts of high density electrical power at a regulated 24 VDC, for a variety of downhole drilling, measurement and logging systems, in environments up to 250 °C (480 °F) of temperature and greater than 20,000 psi (140 kPa) of pressure.  As we drill ever-deeper into the earth,  the temperature and pressure inside the resulting wells generally increase with depth.

This type of turbine generator works by drawing energy from the drilling fluid that is pumped down under pressure from the surface, which is used to lubricate the drill bit and to remove the rock cuttings as drilling proceeds. This fluid passes through a set of turbine blades in the generator tool [shown in the cutaway schematic in Figure 2], which connects with a special permanent magnet generator that then generates power.

The new generator system can replace disposable lithium and rechargeable lithium ion batteries, which are commonly used in these systems.  Because these batteries do not operate above 200 °C (390 °F), they limiting the cycle time and depth of drilling for systems that use them.  Using the turbine generator means that in addition to oil & gas well drilling, the tool could also have applications for geothermal drilling, which can experience even more demanding conditions.

My colleague Tim Price, Dexter’s Business Development Manager for the oil & gas industry, said:

“The development of HPHT measurement and logging tools has outpaced the availability of safe and reliable HPHT power supplies. Dexter’s HPHT downhole generator was developed specifically to fill that void. We have a downhole power supply that provides regulated power from subzero surface temperatures to 250 °C (480 °F) bottom hole formation temperatures. No other single commercially-available technology can provide power over that operating range as of this date.”

Tim went on to say that:

“The need for such HPHT power supplies appears to be greater now more than ever, with the high temperature, extended reach horizontal drilling experienced in plays such as the Haynesville Shale.”

Performance data on the HPHT downhole generator products can be acquired directly from Courtney Stone, Marketing Manager at Dexter, or from me.  We are now actively looking for partners in the well drilling industry, to participate in field trials and qualification of the new HPHT downhole generator tool, in wells with formation temperatures expected to exceed 175 °C (350 °F).

Get in touch with me if that describes you or your company!

Flywheels work on the basis of imparting energy into a rapidly rotating mass, which can then be tapped for later use.  They are a well-established method of providing back up power for commercial power utilities, and more recently, they have started to see use in regenerative braking applications for vehicles, where the energy from braking is transferred into a flywheel [instead of the alternative electrical generator approach].

It is to this latter application that the Kinergy is apparently being applied.  In Figure 1 we can see a cutaway model showing the insides of the device. The blue-and-yellow components represent the magnetic gear system.

The Ricardo Web site says that:

[t]he range of potential Kinergy applications is significant not least due to its comparatively very low projected production costs. The technology is thus ideally suited for use in road vehicles where regenerative braking and torque assist is employed as a means of improving efficiency and hence reducing fuel consumption and CO2 emissions. Such potential applications range from small, price-sensitive mass-market passenger cars to large luxury SUVs, buses and trucks. Across all of these vehicle categories, Kinergy offers the prospect of enabling effective hybridisation extending into market sectors where the use of conventional electro-chemical battery systems technology would be prohibitively expensive.

They go on to say that:

Further potential Kinergy applications also include low-cost, compact energy management and storage systems for use in industrial and construction equipment, elevators, railway rolling stock, and local electrical substations and power distribution systems.

Magnetic gears of this type are relatively new, and there are not too many commercialized applications for them as yet. The systems generally consist of three concentric sub-systems which allow for the conversion of speed into torque and vice versa, without contact between the sub-systems.  They can also be combined with electrical motors and generators to form some very interesting electrical machines.

Ricardo says in the excerpts above that they anticipate “very low projected production costs“. Magnetic gears are not cheap to build, because of the labour involved, so one would have to surmise from this statement that in relation to the system as a whole, the gear sub-system is not a major cost driver. Certainly there are some significant advantages to magnetic gears over and above mechanical gears, to make them worth considering.

Ricardo is working on the use of the Kinergy concept in a demonstrator FLYBUS vehicle based on an Optare Solo bus, as shown in Figure 2.

Figure 2. FLYBUS demonstration concept, using the Ricardo Kinergy flywheel system. Courtesy of Ricardo (2009)

I’ll be posting more on magnetic gears in the near future, and I will be presenting a review of magnetic gears and related electrical machines at the Magnetics 2010 conference in Florida, next January. In the meantime, you can read the rest of the article on Kinergy here.

Microfluidics involves the control of fluids in very small channels and containers. According to the article:

The NIST connector employs a ring magnet with a O-ring gasket on its bottom and a tube in its center set directly atop the inlet or outlet port of a microfluidic channel embedded in a glass chip. A disc magnet on the underside of the chip holds the first magnet — and its tubing — securely in place.

According to the abstract of the original paper on which the article was based, “interfacial forces in the range of 2-15 N” have been achieved.

The folks at NIST do warn that while these connectors are suitable for a range of microfluidic applications, they are not suitable for use with magnetic nanoparticles or at higher temperatures.

You can get more details on this application here.

Over the past few days, Australia’s ABC Radio National broadcast not one, but two items on rare earth metals, to both of which I heartily recommend listening.

The first item was broadcast on the Breakfast program on Friday, and lasts a little over 6 minutes.  It’s an introductory piece on the subject, but spends significant time discussing the environmental issues surrounding rare earth production in Australia. You can listen to the piece on the program’s Rare Earths Metals segment Web page or by clicking below:

ABC Radio National Breakfast: Rare Earth Metals

The second piece, first broadcast on the Background Briefing program this past Sunday morning, lasts for over 45 minutes and is an comprehensive, in-depth study of the rare earth metals, their markets and associated supply chain, environmental and political issues.There is also a pretty decent-sized portion on rare earth permanent magnets and their applications, for which, in the interests of full disclosure, I was interviewed :-)

As producer and narrator Stan Correy says:

China currently produces about 95% of the world’s rare earths, which are metals which are essential to modern living and used all around us every day. In business it’s a volatile mix, with complex political alchemy for every government, including Australia.

The program features several interviews of a variety of individuals from a number of different sectors, in addition to yours truly.

You can listen to the piece on the Background Briefing Rare Earths and China program Web page or by clicking below:

ABC Radio National Background Briefing: Rare Earths and China

Stan did a great job in explaining what can be a difficult subject to convey.  He also included a link back to Terra Magnetica – so thanks, Stan, for that!

The place? Denmark… home of wind turbines, pickled herring and Kierkegaard. Not the first place you might expect the Prius and Roadster to come together, but the Fates must have had their reasons.

Steen Joregensen’s friend had had his brand spanking new Tesla Roadster for the sum total of 14 days, with 400 miles on the clock.  Being the kind soul that he was, Steen’s friend let him take it for a spin.  As he waited at a red stop light due to construction on the highway, out of nowhere came the Toyota Prius.  Before he knew it…

[[Visit blog to check out this spoiler]]

There was a reasonable wind blowing at the time of my visit and the turbines were moving at around 15-18 RPM.  Standing directly under the blades I could certainly hear them moving, but it wasn’t as loud as I had expected, and after moving just 50-100 yards away the sound diminished significantly.

The University also has a mast close to these turbines in order to measure wind speeds at different heights above the ground, as part of their research into efficiency of production.

Here are some photos…