Original Date: 11/03/1996
Revision Date: 01/18/2007
Information : High Performance, Direct-Drive Motor
Oak Ridge Centers for Manufacturing Technology (ORCMT) established a Cooperative Research and Development Agreement (CRADA) with Quick-Rotan, Inc., the only remaining U.S. manufacturer of sewing machine motors, to develop a small, high-efficient, direct-drive motor which could be mounted on the top of commercial sewing machines. This new motor would revolutionize the apparel industry by eliminating the large, belt-driven AC servo- motors which were mounted underneath the sewing machine.
Various obstacles were faced during the development of the new motor. To meet required specifications, ORCMT and Quick-Rotan modified an existing motor which allowed it to be integrated onto a sewing machine shaft. Next, they designed a control system which enabled the motor to stop at the needle-up position and accurately step up and down from 10,000 rpm.
The completed CRADA project produced a 1.4 hp, permanent-magnet, DC motor (approximately the size of a soda can) which can successfully drive a commercial sewing machine at speeds up to 10,000 rpm. Top speeds of previous sewing machine motors ran at 5,000 rpm. Advantages of this top-mounted, direct-drive motor include easier swapping of motor heads, less maintenance (no belts or pulleys), less heat, and more operator leg room. A direct- drive DC motor can deliver more torque with less power loss from friction or gearing, allowing a 1:1 ratio of rpm to stitches per minute to be achieved; previous motors had a lower ratio. Demonstrated at the 1994 Bobbin Show, the new motor received rave reviews and easily exceeded other motors developed by overseas competitors. The apparel industry has long sought this innovation which will lead to more cost-effective production and faster maintenance.
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