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Mag Lab Reclaims World Record for Highest Field Resistive Magnet
Physicists who do research at the National High Magnetic Field Laboratory at The Florida State University got a brand new, high-tech toy for the holidays – a world-record magnet.

Engineers and technicians in late December completed testing of a 36-tesla magnet. Tesla is a measure of magnetic-field strength; the new magnet is more than 1,200 times stronger than a typical refrigerator magnet. This achievement reestablishes the Magnet Lab as the world-record holder for the highest-field "resistive" magnet, a type of electromagnet that uses electricity to generate high magnetic fields. The new magnet, actually an upgrade to an existing one, bests the previous record of 35 tesla, jointly held by the Magnet Lab and the Grenoble High Magnetic Field Laboratory in France.

"This latest world record is a credit to the ingenuity of the magnet lab's engineers," said Nathanael Fortune, chairman of the National High Magnetic Field Laboratory's User Committee and an associate professor of physics at Smith College in Massachusetts. "The Magnet Lab's competitive edge in science and technology depends on continuous enhancements to the lab's facilities, and users will be thrilled to reach higher fields without increasing the amount of electric power required to get there."

Engineers at the magnet lab are driven to push magnetic fields as high as possible: They never stop fine-tuning, tinkering and rethinking their magnet designs. This explains why the laboratory holds numerous records, 13 at last count, for strength of field and other key measures of high-magnetic-field research.

Resistive magnets are built in-house at the magnet lab using so-called Florida Bitter technology pioneered by researchers there. Circular plates of copper sheet metal are stamped with cooling holes; insulators with the same pattern are placed between the plates and stacked to make a coil. Voltage is then run across the coil and current flows to make a magnetic field in the center. Because of the limits of available materials (both to conduct current and to minimize stress on the coils), engineers were stuck at 35 tesla for about four years.

But Magnet Lab engineers discovered that by adjusting the stacking pattern of the bitter plates, they could increase the magnetic field without increasing stress on the coils. This 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.

The 36-tesla magnet, which has a 32-millimeter (1.25-inch) experimental space, will be used primarily for physics and materials science research.

Jingping Chen, manager of the resistive magnet program at the Magnet Lab, said the upgrade of the magnet is just a start, and that major upgrades are planned for many of the resistive magnets at the laboratory.

"We believe this magnet has the potential to reach even higher fields," Chen said. "We plan to upgrade our other 35-tesla magnet this year as well. And our wider-bore, 31-tesla magnets will be upgraded to around 33 tesla, which will be a new record in the 50-millimeter (1.97-inch) category."

MEDER electronic, Inc. - 5mm Ultra-Miniature Surface Mount Reed Sensor Boasts High Performance
MEDER electronic’s MK24 series Reed Sensors achieve a minimum life expectancy of 50 million operations at 5 V, 5 mA, 100 Hz while measuring only 5 mm by 1.8 mm by 2.2 mm.  At 50 millions operations, the MK24’s base reed switch, a 4 mm KSK-1A04 unequivocally surpassed all other reed switches in its size class.  The MK24 reed sensor is a hermetically sealed switch in a robust thermoset molded package. This tiny energy saving device requires no external power to operate, cutting down on  power consumption costs making them especially well suited for low power applications while reducing space requirements.  Sensitivity ranges from 1.5 to 10 mT are available. 

This miniature sensor series is perfect in applications where size is critical, while its flat contacts provide the added benefit of effortless contact orientation during PCB assembly.  Available in 3 lead designs, the MK24 series are sold in Tape & Reel packaging and are suitable for pick and place automation.

Capable of switching up to 3 watts with individual maximum ratings of 0.5 amps and 5 volts; the MEDER MK24 series surface mount Reed Sensors have a minimum breakdown voltage of 100 VDC across the contacts. These reed sensors are RoHS compliant.

Honeywell Releases Next Generation 3-Axis Compass Chip
Honeywell has released a three-axis digital compass circuit that enables directional pointing and location features in consumer electronics including handheld devices, gaming, and personal navigation systems.

The Honeywell HMC5883 chip-scale three-axis compass integrated circuit delivers up to 1 degree heading accuracy from a small 3 by 3 by 0.9 mm surface-mounted chip. The HMC5883 includes a built-in offset cancellation circuit and auto calibration software that simplify the calibration process, eliminating the need to calibrate by swinging a mobile phone in a "figure eight" pattern as with other sensor technologies. In addition, patented set/reset straps that demagnetize, or degauss sensors for each measurement make the HMC5883 immune to most large magnetic disturbances, reducing the need to recalibrate.

The HMC5883 offers the highest resolution available in a chip scale package and maintains heading accuracy in reduced magnetic field environments such as buildings and automobiles, or at high earth latitudes where the declination angle of the earth's field is difficult to sense with Hall type sensors. The HMC5883 includes three-axis Anisotropic Magnetoresistive (AMR) sensors, signal conditioning and amplification circuitry, a 12-bit analog-to-digital converter, built-in self test, and an I2C serial bus interface.

The HMC5883 has a selectable dynamic range of up to ±10 gauss, providing maximum resolution to measure earth's magnetic field of ±0.5 gauss in mobile devices, whose stray magnetic fields are typically less than ±4 gauss, and provides better than 0.05 percent non-linearity over a typical operating range for precision sensing of the earth's magnetic field. Superior resolution is maintained over the full dynamic range ensuring accuracy for a broad range of applications under demanding conditions.

"Consumer electronics can now have the accuracy of AMR sensors at the pricing of Hall-effect sensors," said Keith Nootbaar, Sr. director Honeywell Microelectronics and Precision Sensors. "Unlike Hall-effect type sensors, our 3-axis sensor accurately measures ultra-low Earth magnetic field strengths, even in higher latitudes such as northern US, Canada, and northern Europe or while in the presence of stray magnetic fields such as in buildings and automobiles. The high dynamic range of Hall type sensors may provide easy board design but at the cost of accuracy and resolution that is required for some of the precision apps that are being developed."

Honeywell's HMC5883 compass chip leverages on STMicroelectronics' manufacturing expertise and high volume capacity for LGA packages with more than 600 million motion sensors in the field and excellent acceptance from the Market," said Benedetto Vigna, Group VP and General Mgr of MEMS, Sensors and High Performance Analog Division.

The HMC5883 is supported by a complete library of software routines for heading, auto calibration and soft iron/hard iron calibration, supporting a variety of popular mobile phone operating systems. The software is common with the recently introduced STMicroelectronics LMS303DLH six-dimensional sensor with integrated 3-axis magnetic sensor and 3-axis accelerometer, providing designers with a low risk way to support multiple integrated and federated platforms.

Electro-Permanent Magnetic Clamping System from Schunk
Schunk, Inc. is expanding its workholding product range with several new lines of magnetic clamping. The new lines include a complete line of permanent and electro permanent grinding and EDM magnets, bipolar magnets for holding round bars to cut Key-Ways and Whip Stocks and Radial magnets for VTL’s to hold rings, as well as other magnets for special applications.
           
With Magnos, Schunk relies on the innovative technology of electro-permanent magnets, which require only a short pulse of electricity to activate and deactivate the magnetic field. A uniform clamping force is possible thanks to the poles’ quadratic geometry. Reliable clamping, even during rough machining, is ensured by the high holding forces of the magnets. Different pole sizes of 32, 50, 75 and 100 mm are available, enabling the holding forces to be tailored to individual requirements.

The advantage of magnetic workholding is that it enables five-sided machining with high holding forces, without any interfering clamps or distortion to the workpiece. Pole extensions that act as workpiece support allow the user to position different workpieces rapidly and precisely thus improving the productivity and capacity of the machine.

When combined with the Schunk UNILOCK quick-change pallet system, the magnetic clamping plates can be equipped with the UNILOCK clamping pins. Such flexibility in production opens the door to countless possible applications.

BEI Kimco Releases Robust, High Temperature Motor
BEI Kimco Magnetics, a company of Custom Sensors & Technologies (CST), Inc., recently met the challenging high-performance motor requirements for a Down Hole Measurement While Drilling (MWD) application. With oil companies drilling deeper than ever before to obtain increasingly valuable deposits, components within the drill tool must deliver reliable operation at the most extreme ambient temperatures. 

Key to the down hole tool string design was a motor  capable of extended operation at elevated winding temperatures of up to 220°C and pressures approaching 30,000 PSI.  The motor would be used to position a sensor that would take measurements of the materials encountered during the oil exploration operations.

To meet the manufacturer’s requirements, BEI Kimco developed a High Performance Motor measuring 3.0 inches in diameter by 8.5 inches in length with a custom housing and dual shafts for gearbox and resolver mounting. High energy samarium-cobalt magnets were utilized to provide high operating efficiencies and superior corrosion resistance. The motor was also designed for operation while filled with oil to compensate for the high pressures. These tailor-made features combined to provide a highly robust solution.

“Performing drilling and logging operations at ever increasing depths is extremely expensive and our customers cannot tolerate failure of any of the components within the tool string,” said Walter Smith, BEI Kimco’s senior applications engineer/project manager for Motors.  “If the motor failed to position the sensor properly, the accuracy of the measurement would be compromised and the tool would have to be pulled up.  Time is money, so reliability at these severe temperatures was paramount to the motor’s design.”

BEI Kimco’s motors and actuators with extended temperature operation range capabilities have been used successfully in countless mission-critical applications for many high-end industrial and military applications. The ability to provide high-performance solutions tailored to the specific needs of the customer has allowed Kimco to consistently fulfill unique and challenging OEM requirements.  

Hermetic Switch Introduces New Proximity Sensors
Hermetic Switch, Inc., a designer and manufacturer of reed switches, proximity sensors and other switch technologies, has introduced two new cylindrical (tubular) proximity sensors. Hermetic’s PRX+3800 and PRX+3900 magnetic sensors deliver all the advantages of reed switch sensing technology but with smaller physical dimensions than previously available. These sensors respond to the market need for components with smaller footprints, as size reduction trends continue in the systems and devices utilizing proximity sensors. These sensors from Hermetic can be used in automation, control or detection in a broad array of applications – including safety, security, alarm, equipment, machinery, manufacturing and processing systems – in industrial, commercial, medical, corporate, government or military settings.

Specific applications vary widely and include any number of situations, including extreme environments, where reliable and potentially long-term proximity monitoring is desired but physical contact must be avoided (between the sensor and the object being sensed).

The PRX+3800 is a Form B (Single Pole Single Throw Normally Closed) reed switch contained in a temperature resistant cylindrical (tubular) housing which has a nominal size of 0.125 inch (3.18 mm) diameter and 0.750 inch (19.05 mm) length. The PRX+3900 is a Form C (Single Pole Double Throw) or change-over reed switch with similar housing and dimensions. Both sensors are based on the company’s HSR-502R reed switch technology and operate using a permanent magnet or an electromagnetic coil.

These sensors have an operating distance of 0.250 inches (6.35 mm) and are rated at 2 watts. The maximum operating temperature is 105°C while the storage temperature range is -40°C to 105°C. The sensors are insensitive to electrostatic discharge (ESD), which makes them well suited for applications where ESD is a concern. Custom wire and connector configurations are available upon request. See below for data sheets.

Pricing for the PRX+3800 and PRX+3900 is in the range of $5.00 to $7.00 each  depending on quantity.  Pricing is also affected by additional options such as custom sensitivity, custom configuration, and special wiring or connectors.

Magnetics 2010: Conference Proceedings Now Available
If you were unable to attend MAGNETICS 2010, you can still stay up-to-date on the latest magnetic applications, technologies and materials.

For only $290 you can purchase the entire conference proceedings on CD-ROM which includes:

• PDFs of the slides to more than 25 presentations; including audio and video of select sessions
• Product and services information from exhibiting companies
• Attendee Information (Name / Title / Company / City / State)

It’s the next best thing to being at the Conference! To order click here, or email Julie Williams.

Micrometals, Inc. Acquires Arnold Powder Cores from Arnold Magnetic Technologies
Micrometals, Inc. has purchased the powder core business unit from Arnold Magnetic Technologies. The acquisition includes the manufacturing facility in Shenzhen, China along with the Hong Kong sales office. This addition will expand the Micrometals product offering of well known Iron Powder and 200C series cores to include Arnold’s extensive range of MPP (molypermalloy powder), SUPER-MSS (sendust), HI-FLUX (50/50 nickel iron), Fe-Si (iron silicon) and other alloy based powder cores.

“This addition will give Micrometals the widest selection of powder core materials and sizes in the industry,” said Micrometals’ President James R. Cox. “We plan to capitalize on the natural production synergies while emphasizing our strong engineering support and customer service.”

The full line of Arnold Powder Cores will continue to be manufactured at the factory in Shenzhen, China. The part numbers will remain unchanged, and the existing Arnold Powder Cores sales and distribution channels will stay intact to provide a seamless transition.

Avalon Commences Exploration Drilling on East Kemptville Tin-Indium Project
Avalon Rare Metals, Inc. has commenced a 2,000 meter diamond drilling program on its exploration licenses in the East Kemptville area, Yarmouth County, Nova Scotia. Ten holes are planned to test three target areas for tin-indium-copper-zinc mineralization similar to that of the past-producing East Kemptville tin deposit. Drilling commenced on January 18th and will continue for about three weeks. Avalon is also re-evaluating the potential for renewed tin-indium production at the East Kemptville mine site in a Preliminary Economic Assessment (PEA), being conducted by Wardrop Engineering.

The East Kemptville deposit is a greisen, or hydrothermal replacement zone, associated with the contact of a regional granite intrusion known as the South Mountain batholith. This contact has been traced over a strike length of at least 10 km southwest from the mine site, where it is favorable for the occurrence of additional tin-indium-copper-zinc deposits. Limited outcrop exposure in the area necessitates the use of geophysical and geochemical methods to define drill targets. Several such targets have been defined through the compilation of historical data supplemented by new surveys completed intermittently by the Company over the past 18 months.

The top priority target is known as Gardner's Meadows where a combined geophysical and geochemical anomaly company is supported by anomalous tin values reported from limited historical drilling. The anomaly was defined on the ground over an 800 meter strike length by recent induced polarization (IP) surveys, magnetics and soil surveys, using Mobile Metal Ion techniques (MMI). At least four holes will test this target. The entire work program has a budget of $500,000.
Growing demand for both tin and indium from the consumer electronics industry has resulted in strong prices and opportunities for new producers. In particular, tin is increasingly being used to replace lead in solders applied on electronic circuit boards due to lead toxicity issues. Europe, China and California have all recently passed laws requiring the use of lead-free solders in electronics, for which tin is the most economical and reliable substitute. Tin and indium are also used as an alloy in flat-screen display panels, while indium is alloyed with gallium in CIGS (Copper Indium Gallium Selenide) solar power panels, all of which are expanding markets.

Prices for tin have been quoted recently on the London Metal Exchange at over $8.00/lb compared to less than $2.00/lb when the mine ceased operations in 1992. Indium (99.99 percent purity) is currently trading at prices in excess of $500/kg in China.

Hk: A Key Magnetic Figure of Merit
By Steve Constantinides, Director of Technology • Arnold Magnetic Technologies Corp.

The quality of permanent magnets is defined by several parameters such as Br, Hci, BHmax, permeability (μ) and reversible temperature coefficients of induction and coercivity. All these are measured parameters. Engineers designing devices for use at other than room temperature or in the presence of a demagnetizing field also use a characteristic describing the quality of the intrinsic curve. This calculated value, Hk, is too little understood and alternative definitions of curve quality are appearing.

Read full article here.

Download a PDF Copy of the WINTER 2009 Issue of Magnetics Business & Technology Magazine

Feature Articles:

Initial Thoughts to Help Eliminate Some EMI Problems
Going Forward: The Delicate Supply Balance and the Growing Demand for Rare Earths
What Rare Earth Crisis?
Hk: A Key Magnetics Figure of Merit

Columns:

Guest Column: The Magnetized Tail Wags the Motorized Dog
Spontaneous Thoughts: The Disregarded Experiment

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