New technology boosts energy efficiency of single-phase motors

-- Control Engineering, 10/26/2006

Power Efficiency Corp., a developer and manufacturer of advanced energy savings technologies for electric motors, says it has successfully completed internal tests on a new microprocessor-based technology for reducing electric power wasted by single phase alternating current induction motors. These motors, typically found in shop tools and light commercial and industrial equipment, waste electricity when lightly loaded. While the new technology attacks power waste in any lightly loaded motor, the new approach is most suitable for single-phase motors.

This approach uses a new algorithm run by software on a microprocessor to achieve energy savings claimed to be over 30%. The company believes it is a breakthrough and expects to file a provisional patent in the coming months.

"Historically, energy efficiency measures for appliances have focused on other areas, such as seals, insulation, and lighting in a refrigerator,” says Steven Strasser, Power Efficiency's Chairman and CEO. “But the compressor motor in a refrigerator uses the most electricity. We believe our digital controller may be the simplest and most cost-effective technology to reduce the energy consumed by many of the appliances."

The new technology is based on an adaptation of the company’s first product, Power Genius, which reduces energy used by larger electric motors in applications such as escalators, elevators, grinders, granulators, mixers, saws, and stamping presses.

Controllers using Power Genius allocate power in direct proportion to the motor's workload, eliminating wasted electricity. The core technology is based on patented improvements to NASA technology. The company claims energy savings are typically 20-40% in appropriate applications. The controllers also reduce heat dissipated the motor, producing significant motor life extension and downtime reduction benefits.

For the development tests, the company used a Baldor L3501 single-phase, 1/3-hp general-purpose capacitor-start motor powered by 120 V single-phase ac. According to Baldor, this model is typically used for compressors, pumps, fans, farm equipment, conveyors, material handling equipment, machine tools, and other similar applications. During the tests, technicians loaded the motor using two Magtrol Model HD-510 and Model HD-810 hysteresis dynamometers.

Under no-load conditions, the digital energy control algorithm provided over 30% energy savings. At 40% of full load, the technology still provided over 20% energy savings.

Power Efficiency Corp. plans to market the technology for small, single-phase motor primarily through sales and licensing agreements with manufacturers of refrigerators, shop tools, vending machines, and residential air conditioning, and has begun initial discussions with companies in these sectors about testing the new technology on their equipment. They expect to move soon into application-specific testing with independent verification.

"With this new technology, Power Efficiency Corp. is targeting the large market of home appliances and light commercial and industrial equipment," said Strasser. "For example, in 2005 there were more than 14.5 million residential air conditioners and 13.5 million refrigerators and freezers sold in the U.S. alone.”

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