issue: September 2003 APPLIANCE Magazine Motor Technology Quiet A.C. Gearmotors	Share  Printable format  Email this Article  Search
The V Series of a.c. gearmotors from Oriental Motor USA Corp. (Torrance, CA, U.S.) is said to offer foodservice equipment and medical device producers a quiet, reliable solution.

According to John Wong, senior engineer at Oriental Motor, the company adopted a series of comprehensive noise-reduction techniques to achieve this improved performance, including a special tooth process technology that removes machining marks of 1 to 2 microns from the surface of motor pinions.

"Improved machining techniques improved the flatness or smoothness of the pinion gear surface," explains Mr. Wong. "Additionally, after machining, the pinion surface was coated with a varnish-type material that further improved the smoothness of the surface by filling in any tool marks or scratches. When mating surfaces are smoother, they produce less audible noise."

The motors also feature an optimized quiet running design that reportedly reduces eccentricities and out-of-balance conditions. Mr. Wong says the key is a smaller diameter pinion. "A smaller diameter pinion reduces the circumferential speed (fpm) at the OD of the pinion, compared to a larger diameter pinion running at the same rotational speed (rpm)," he says. "By reducing circumferential speed, we minimize the noise generated from the gears meshing, eccentricity, and out-of-balance conditions."

The company also made manufacturing improvements in the pressing dies to further minimize any misalignment of the gears with respect to the shaft. In addition, by utilizing a more rigid gear case and a new side-panel design, any misalignment of the gears due to bending of the gear case is said to be further minimized. "Any time you can reduce misalignment, you reduce the amount of vibration and noise that is generated within the gear case, resulting in less overall noise," Mr. Wong notes.

The V Series motors feature strengthened shafts that mate to a series of long life (10,000 hr) GV gearheads, which reportedly achieve up to a three-fold increase in maximum permissible torque levels.

The motor series provides output power levels of 6, 15, 25, 40, and 60 W, depending on motor frame size, and includes induction, reversible, and electromagnetic brake motors. The a.c. motors can be supplied as single-phase 110/115 V a.c., single-phase 220/230 V a.c., and three-phase 200/220/230 V a.c. inputs. Terminal box and lead wire models are available.

Oriental Motor's V Series of a.c. gearmotors have been used in applications such as obstetrics beds, large projection screens, medical conveyor equipment, and commercial bun toasters. They have also been used in countertop continuous fryers, which are commonly used in Japanese convenience stores to fry food for ready-to-eat meals. According to the company, motor reliability is key in this application because there is no room - or time - for maintenance.