Appliance Design - March 2009 - (Page 19)

POWER 80 percent efficiency, the issue could impede greater usage as some consider the downside of energy waste not worth the convenience factor of eliminating a power cord. While work continues to improve transfer efficiency, it is not certain how much improvement can be made to overcome the inherent difficulties caused by distance. On the other hand, in some applications the ability to charge from a distance is more important than losing a percentage of power during transfer. A soldier recharging a field radio, for example, might not care that only 50 percent of the power is actually making it to the device. Another crucial concern for broadcast technology is to ensure that the energy being broadcast does not harm either people or other electronic devices that come between the transmitter and receiver, an issue that the more direct contact technologies do not have to face. According to Schatz and others, the fields that are transmitted fall well within regulatory guidelines and emissions will not interfere with other electronic devices. Having said that, Smith says that he can foresee some cases where certain components within a device may require shielding. He anticipates that that would be no greater than the shielding that is commonly used in many electronic devices. The energy transmitted is not considered a safety hazard, according to the suppliers. Powercast, for instance, says that the RF energy that its units transmit is less than those encountered during every day life. In terms of resonant inductive coupling, Smith says that the coupled magnetic fields that are transmitted are safer than electric fields. Electric fields interact with the water in a person’s www.applianceDESIGN.com AD03094Epcos3.indd 1 b o d y, which magnetic fields do not do. The reasoning is that the H20 molecule is a polar molecule with an electrically positive end and an electrically negative end, according to Intel. A water molecule within an electric field will tend to align with the field and when the field is oscillated, the water molecule will oscillate as well. This is how a microwave oven pops popcorn. Magnetic fields, on the other hand, go relatively unnoticed by water molecules or any other molecule in a body. Despite this, Smith says that consumers will almost certainly question the safety of the technology and these questions will need to be answered. Despite these issues, the developers of broadcast wireless power transfer technologies, along with developers of the other methods, are all enthusiastic about future prospects. The cell phone industry alone, with its more than 1 billion units sold, is enticing. And, the ability to make the consumers life simpler and less cluttered might make wireless power transfer the next hot concept that captures the consumer’s attention. < For more information, email: Fulton Innovation: ecinfo@fultoninnovation.com Intel: megan.e.langer@intel.com Powercast: sday@powercastco.com Powermat: sales@powermatUSA.com WildCharge: corporate@wildcharge.com WiTricity: david.schatz@witricity.com WildCharge sells adapters with built-in contact points for specific electronic devices. The adapter for a Motorola phone replaces the phone’s original battery cover. Filter. Stabilize. Optimize. Maximize performance of electronics with EPCOS chokes and inductors. High noise suppression High resonance frequency ■ High current ratings ■ Compact size ■ ■ Call 888-768-2673 www.epcos.com/ inductors applianceDESIGN March 2009 19 1/15/09 11:48:46 AM http://www.epcos.com/inductors http://www.epcos.com/inductors http://www.appliancedesign.com

Table of Contents Feed for the Digital Edition of Appliance Design - March 2009

Appliance Design - March 2009 Contents Editorial Shipments/Forecasts News Watch Transmitting Power Wirelessly Promises to Reduce the Ever-Growing Tangle of Cords and Cables Found in the Modern Home. There Are Different Technological Approaches for Achieving this Goal, and Some Are Already on the Market. Electrochemical Capacitors Can Provide an Extra Peak-Power Boost in Battery-Operated Appliances, Allowing Product Designs to Have Smaller Battery Packs. Metallic Foams Put the Properties of Metals into Lightweight Packages. Applications for this Emerging Technology Include Gas Burners, Heat Exchangers, and Electronics Housings. Hall-Effect Switches Are Compact and Provide a High Degree of Reliability and Durability as They Virtually Eliminate Mechanical Wear, Shock, and Contact Oxidation. Blowing Agents for Polyurethane Foam Insulation Face Increased Scrutiny Due to Global Warming Concerns, but Alternatives with Lower GWP Values May Provide Solutions to Meet These Challenges. Design Marts Association Report: AHAM Advertisers' Index

Appliance Design - March 2009

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