Page 10 - Industrial Technology EXTRA 19th July 2021

ELECTRIC MOTORS...

Thermal management tips for

miniature DC motors

Converting electrical energy into mechanical power naturally generates heat. In the

case of miniature electric motors, it is vital that temperatures are managed to avoid
component failure. To optimise performance and efficiency, this means that the motor
manufacturer has to design the right thermal management solution according to the
application requirements. Daniel Muller of Portescap, explains the thermal
management considerations your miniature motor manufacturer should make.

xcess internal temperature will
damage a motor and its components.
Even before it gets to that stage,
Ethermal management impacts
performance, not least by power conversion
efficiency. When developing a miniature motor,
it’s vital to ensure that the design and
materials used minimise losses to heat, as well
as improve the motor’s heat dissipation ability.
A coreless brush DC motor is typically
designed as a self-supporting coil rotating in
the airgap between a permanent magnet and
housing, which are both part of the stator. As
the coil temperature rises, the heat transfers
from the coil to the tube and then from the
tube to the ambient environment. As electrical
current flows through the coil, its temperature
rises, heat dissipation begins and increases to
a point where it exactly compensates the heat
generation. At this point, thermal energy
contained in the motor is constant over time.
Brushless motors use the same working
principle as brushed motors except that the

July 2021 • INDUSTRIAL TECHNOLOGY EXTRA • p10