One of the key features of the new series of gearmotors
is its low noise threshold of 29 dB, a reduction of approximately
6 dB when compared to the company's other a.c. motors.
issue: September 2003 APPLIANCE Magazine
Quiet A.C. Gearmotors
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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
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
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.
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
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.
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.