SERVO 11.2015 23
spur gear on the motor were
engaging the planet gears in the
gearbox. This overloaded the teeth,
and they deformed on both the motor
(Figure 3) and the first stage in the
gearbox until it locked up. One of the
planet gears can be seen in Figure 4
next to an undamaged tooth. I
dismantled the rest of the gearbox
but there was no further impairment.
This damage would have sent
most gearboxes into the trash can or
the spare pile, but there is a big
advantage in using the BaneBots P60
You can get replacements
for all the various parts.
The motor would go in
the trash but I already
had a replacement for it
(Figure 5), so all I
needed was four new
planet gears (less than $8
total plus shipping, saving
a lot over the $50+ for a
complete new unit).
While I was waiting
for those to arrive, I made
sure the tabs on the new
motor and the other
undamaged one were
fully formed (Figure 6) by
bending them over using
a flat bladed screwdriver
and a few taps with a
hammer. This should do
the trick, but one could
also add a bead of epoxy
adhesive around the lip of
the end plate to make
this failure really unlikely
in the future.
When the new gears
arrived, I cleaned all the
parts and reassembled it
with fresh grease (Figure
7). This is messy, but not
difficult; just note
carefully what gear goes where as you
take it apart. The motor mounting
plate was removed from the old
motor and fitted to the new motor. It
(and then the motor) and gearbox
were attached together with the four
long screws to complete the assembly.
I now had two good units (Figure 8)
to go back into Isotelus.
This is where the plans changed.
I had been testing some
HobbyKing 45A brushless ESCs
(electronic speed controllers) to see
how well they worked — both for
powering weapons but also for driving
the wheels of a 12 or 30 lb bot. I had
built a test chassis using a couple of
2848 Tacon brushless motors with
Figure 2. Damage
Figure 4. Good
and bad gears.
Figure 6. Fully formed tab.
Figure 7. Replacement planet gears.