SERVO 11.2015 29
also known as a
1230 motor —
packs 30 watts
of continuous
power. For
reference, a
common 13 mm
Maxon brushed motor is rated for
only three watts continuous power.
Figure 2 is an example of a 1230
brushless motor with a 4,800 KV
wind.
The 1230 motor has a very small
mounting face pattern that appears to
be designed for a single stage plastic
spur gear. A metal planetary gearbox
with several stages of reduction would
provide a better solution. The 13 mm
Maxon gearbox would be perfect as
there is a large number of used 13
mm Maxon gearmotors on eBay; the
gearboxes rarely have any wear, but
some customization is required.
Both the 13 mm Maxon brushed
motor and brushless 1230 motor
share the same 1.5 mm diameter
shaft. You just need to core out the
Maxon motor and use the motor
frame as a mount for the brushless
motor. Figure 3 shows the thread
mount the motor uses to interface to
the gearbox.
To remove the pinion from the
motor shaft and allow the motor shaft
and rotor to be removed from the
motor, a small torch or soldering iron
can be used to loosen permanent
Loctite. This is shown in Figure 4.
Figure 5 provides a sum of all the
motor components. To continue the
process of removing the rotor, the
rear brush assembly and cover can be
removed by inserting a small
nail or peg into the cover
hole and forcibly breaking it
out. Once the brushes are
out of the way, the rotor can
be removed by using a small
peg to hammer the pinion
side of the shaft down and
through the motor.
In Figure 6, use the
same peg enlisted to push
out the shaft and rotor to
push out the center magnet assembly.
The magnet assembly should come
out leaving only the motor can and
front thread mount as shown in
Figure 7.
The inside diameter of the motor
can is slightly less than 12 mm in
diameter, so it must be opened up
with a 12 mm drill bit. This can be
done in a metal lathe or even a drill
press. It is preferable to grip only the
thick thread mount body area. A drill
collet could be used to apply equal
force in holding the motor can.
Figure 8 demonstrates a
lathe setup.
Finally, after test-fitting
the brushless motor into the
Maxon motor body, use
permanent Loctite to secure
the brushless motor into the
body. Apply the Loctite to the
upper circumference of the
brushless motor and slide it
into the Maxon motor body.
Use the permanent Loctite to
Figure 3.
Figure 4. Figure 5.
Figure 6.
Figure 7.
Figure 8.