Maxon Motor Australia has engineered a range of
brushless DC motors capable of operating at temperatures as high as 180°C.
A brushless DC motor can easily achieve performance specifications
of 376mNm and 1700rpm on 24V. Delivering them at 180°C continuous and 200°C
intermittent can be a little more difficult.
Maxon Motor engineers have been addressing requests
for motors that can perform in the high temperature environments of Australia,
particularly in outdoor and enclosed environments such as mining, solar
pumping, traffic control and agriculture where ambient temperatures in the
enclosure can exceed 60°C. The only modification for this requirement is to typically
use a thicker, high temperature lubrication for the ball bearings.
Most Maxon brushless DC motors are rated from -40°C to
+100°C as standard. However, for motors to operate and perform in 200°C environments,
each component must be designed with a matching thermal expansion. Extensive
finite element analysis, vigorous testing and physical inspections are
conducted on every single assembly process.
Modifications also include avoiding plastics, encapsulating
windings, selecting cable insulation for each environment, and magnets made
from carefully tested grade of Samarium-cobalt rare earth material that is
sintered and again encapsulated. The entire construction is then double pass
continuous flow laser welded, followed by multiple tests.