David Sears, vice president of Technical Services, explains that the motor's
low-voltage feature is achieved through the design of the winding, together
with the magnetic circuit elements. "These items work in concert to
achieve high performance at low-voltage levels, well below the level of
shock hazard, which may appeal to an appliance designer," notes Mr.
In order to operate in harsh environments, Mr. Sears says that all
of the motor's seams are sealed with o-rings, and the shaft is designed
a dynamic seal. "One of the difficulties with sealing such a device
is that the shaft turns, which means that there must be a dynamic seal
at that location," he explains. "The dynamic seal is to allow
shaft rotation, but also provides a secure seal. This is how harsh liquids
are kept away from the bearing at the shaft output, and thereby, are also
kept out of the internal parts of the motor."
According to Mr. Sears,
the new motor was originally designed to drive a pump used within a power
backup system, which is why it is able to operate
under harsh conditions. "The environment in which this motorized pump
must operate places [the] assembly at risk of being splashed with corrosive
fluid. For the intended application, power losses must be kept to an absolute
minimum, while reliability needed to be at the highest possible level," he
The motor boasts 90-percent power efficiency and is fully encased
within a sealed, stainless steel housing. Mr. Sears explains that the
90-percent power efficiency is accomplished by optimizing the motor design
specific load point at which it is intended to operate. "At the target
load point, all elements of power loss have been reduced to the lowest
possible levels, including iron losses, resistive losses, windage losses,
and bearing/seal friction," he says.
In addition, the motor's magnetic
design uses high-energy sintered rare earth magnets, as well as high-grade
bearings, to maximize efficiency for
long life in battery applications.