SBIR Phase I: Interleaved Magnetic Motor Using Flex Circuit Coil

Period of Performance: 01/01/2012 - 12/31/2012


Phase 1 SBIR

Recipient Firm

Custom Transit, Inc.
2500 Packard St., Suite 206
Ann Arbor, MI 48104
Principal Investigator, Firm POC


This Small Business Innovation Research (SBIR) Phase I project will develop a linear, interleaved magnetic motor (LIMM). Magnetic motors are transducers, which convert electrical power into mechanical power according to the Lorentzian force function,F=B×li, where F is Force, B is magnetic flux, l is the length of wire in the gap, and i is the current. Magnetic motors are used in devices such as electric motors in hybrid vehicles, disk drives, linear actuators, and loudspeakers. The LIMM is a unique topological arrangement of the magnetic gap, which creates a long, narrow, serpentine gap. The LIMM's topology allows for the design of transducers, which increase the force, F, faster than the system adds mass, without affecting the width of the air gap. This allows for compact, high power transducers, with almost any quality factor, Q, needed for the system. In order to realize the potential of the LIMM, this Phase I project will focus on selecting an appropriate flex circuit drive coil for use in the serpentine gap. A cascaded design of experiments will be used to identify the correct flex circuit substrate and adhesive, conductor, and forming method, amongst other attributes, to create a repeatable, high-quality transducer. The broader impact/commercial potential of this project is the ability to create compact, high power, low Q transducers using ferrite, rather than neodymium, magnets. China controls 97% of the world supply forneodymium and, recently, has artificially limited supplies. China's cutback in supplies during 2010 sent market prices soaring-neodymium jumped from $41 per kilogram in April to $92 per kilogram in October. The United States has stable access to ferrite magnets. By creating a transducer that exceedscurrent performance demands while using ferrite, instead of neodymium, magnets, the LIMM will reduce our dependence on China as a source of raw material. Additionally, the efficiency gains inherent in the LIMM will also lower the power consumption of the transducer in high current applications. Forexample, a loudspeaker built from a LIMM can easily attain a sensitivity of 96 db at 1 W and 1 m. This is a 6 db increase (or 4x the acoustic power) in output power from the current state of the art loudspeaker. Due to the ease of implementation, speed to market, and performance improvement over current technologies, the first implementation of the LIMM will be in a loudspeaker.