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Wheelchair motors spawn low-cost resolver rival

01 March, 2003

Wheelchair motors spawn low-cost resolver rival

An American company has patented a technology which, it claims, provides a low-cost alternative to resolvers for accurate positioning sensing of rotating shafts. The company, Colorado-based UQM Technologies, originally developed the technology for a range of gearless, brushless, direct-drive wheelchair motors that it manufactures.

The sensor is based on a simple ferrite magnet disk or ring used in conjunction with analogue sensing boards using linear output Hall effect sensors. "Our design not only provides an accurate method of sensing the position of a rotating shaft at a dramatically lower cost than conventional resolvers," says UQM`s director of engineering, Jon Lutz, "but its simple design and topology allows for packaging in axially restrained spaces where the use of a resolver would be difficult or impossible."

UQM chief executive William Rankin believes that the sensing technique will have a broad application in a wide variety of markets requiring accurate sensing of rotating shafts. "We intend to aggressively pursue commercialisation of this patented technology, directly with end-users, and through potential licencing arrangements," he says.