The motor proves the linchpin in this textbook example of design
collaboration between customer and supplier, which has helped Truvox to
develop a cleaning machine for the 21st Century
The Truvox Orbis single-disc rotary floor cleaner is something of a
technical breakthrough in its particular field, where heavy, metal-clad
machines with complex internals have hitherto been the order of the day.
Gone is the die-cast aluminium case and in its place is a much lighter
and easier-to-clean injection moulded plastic housing of a more pleasing
and practical design. However, the single most expensive component of the
cleaner - its motor - posed another problem in this weight saving, cost
trimming exercise, and Truvox (truvox@truvox.com) challenged its existing
motor supplier, Leroy Somer, to come up with a lighter, more cost
effective yet no less powerful unit for the new Orbis. Truvox design and
development team leader, Peter Ward picks up the story.
“In the past, we have always used enclosed motors with a fan on top and a
casing around the rotor and stator. This was unnecessary, as we always
put a case around the motor anyway.” Leroy Somer’s solution was to
develop a new 1.1kW motor with an open frame - improving the cooling,
efficiency and power output while reducing the cost by one third. The
motor also had to be flat and compact to fit in with the aesthetics of
the new design.
The Orbis motor is based on a similar design to that developed for use in
lawnmowers. Thanks to the volume of production for this market, Truvox
was able to share the cost advantages of these economies of scale in the
new motor’s development and production. Leroy Somer is no stranger to
adapting standard products for individual customers and in this instance,
once the open frame construction was decided upon, the company was able
to come up with suggestions and ideas on shaft length and motor mountings
to suit the Orbis application. The two companies worked particularly
closely on the mountings, which are ‘vibration tuned’ rubber units that
minimise the transmission of vibration from the motor to the machine
body. “To optimise the mountings, we used Leroy Somer’s test facilities
to try the machine with a range of mountings,” recalls Mr Ward.
“Together, we were able to determine which rubber mountings produced the
minimum vibration.” A 3D Pro/Engineer CAD drawing of the motor was
supplied to Truvox, enabling the rest of the machine to be designed
entirely in this CAD environment around the motor.
There are three models in the Orbis range: a 187rpm machine for scrubbing
and tougher cleaning jobs; a 400rpm machine for polishing, and a
twin-speed dual purpose machine. The lower speed machine uses a four-pole
230V motor running at 1,500rpm, with a system of pulleys and belts
achieving the speed reduction at the cleaning disc. The 400rpm machine
uses a two-pole motor running at 3,000rpm, again with a pulley and belt
speed reduction unit, while the dual speed model uses a pole-change motor
with four poles that can be switched to two for the higher speed mode.