MANUFACTURING:
Modifying NPC Drive
Motors for C mbat
● by Ray Billings
National Power Chair (or NPC) has been in business for many
years, rebuilding and selling electric
wheelchair motors and parts to
individuals and wheelchair repair
facilities throughout the country.
This depth of knowledge gives them
a lot of experience in dealing with
geared electric motor applications —
something the combat robotic
community has certainly made use
of. A quick review of the top
performers in any of the heavier
weight classes over the years will
show that a large percentage of
builders rely on these motors for
their robotic creations.
NPC ( www.npcrobotics.com)
offers a variety of motors — both
geared and ungeared — but the
focus of this article is around the
most commonly used motor: the
T- 64. The T- 64 has outstanding
torque (a single pair of these
motors can work as drive in a
340 pound super heavyweight!),
is relatively lightweight (I have
60 pounder), and
is versatile —
operating anywhere
from 12V to 36V.
Standard gear
reduction on the
T- 64 is 20:1, giving
an output of 230
RPM at 24V. There
is also an optional
14:1 gearset
(part number
NPC-G1410) that
can be used for
increased speed.
With a wide
variety of potential applications
and its simple “bolt and go”
construction, it is no wonder that
the motors have such appeal.
However, this is still a motor that
was originally designed for a
non-combat application. There are
done to make a great motor even
better.
The motor (as originally
designed for wheelchairs), has a
brake assembly built into the brush
housing. This makes sense in a
wheelchair but not in a combat
robot, so NPC sells these motors
Remove the brushes and these four small nuts, and remove the
brush housing from the motor assembly.
Here are two brush housings: one original and one modified for combat.
The size difference between the two is fairly substantial.
This is a new unmodified
NPC T- 64 motor. You can
see the plastic plate on
the end of the brush
housing that will need to
be removed.
32 SERVO 08.2010
