My son’s 30 lb bar spinner, Glasgow Kiss (Figure 1; which he
is writing a three-part series
about here in the Combat
Zone) competed at the Franklin
Institute event last fall. It was
during one match there that
the shaft on the weapon
motor got bent. After we
returned home, I ordered a
new shaft from Hobby King
and planned to simply rebuild
the motor and reuse it for the
next event. However, when I
dismantled the motor, I found
several of the windings (or coils) had
come loose and been damaged or
cut.
This meant that this part of the
motor would have been high risk to
reuse because a short circuit on one
of those coils could burn out the
motor and perhaps the ESC as well.
I dismantled the replacement
motor — a Turnigy G160 Outrunner —
by removing the snap clip and two
washers (Figure 2) that secured the
stator to the rotor (Figure 3). The
snap clip requires a special pair of
pliers. I found the ones I use to put
the clips on the popular snap hubs
and fitted the clips on the motors.
Close examination of the stator
(Figure 4) showed that there was a
little resin securing the coils but there
were still some loose wires and many
that didn’t look very secure.
I bought some one minute epoxy
at my local Home Depot. It came with
a couple of mixing nozzles which
allow you to mix and apply the resin
at the same time. After a brief
discussion on Facebook, I warmed the
resin first to reduce its viscosity in a
cup of near boiling water (Figure 5)
and applied it to the top of each set
of windings. It flowed down into the
windings and quickly set (Figure 6). (I
wiped off any excess resin using a rag
before it set.)
Make sure no resin
gets in the bearings or on
the outer diameter of the
stator. I think that next
time I do this, I’ll use five
minute epoxy rather than one minute,
in order to give additional time to let
the resin sink in more.
Glasgow Kiss competed using the
new motor. In a tough fight, it again
suffered damage (Figure 7) when the
hit dislodged the snap clip, and
allowed the rotor to move up and hit
the coils, then bounce back and move
partially apart from the stator.
A smashed magnet in the rotor
jammed it in the partially out position.
However, it can be seen that although
the epoxy resin has been scuffed in
30 SERVO 07.2016
PARTS IS PARTS:
Coils of War ● by Pete Smith
FIGURE 1.
FIGURE 3.
FIGURE 4.
FIGURE 2.
www.servomagazine.com/index.php/magazine/article/July2016_Parts-is-Parts-Coils-of-War.
