Merc-O-Tronics 98 - ARMATURE GROUND TEST; Armature Ground Test Procedure

sM&L &rcX
LED
rc GrcUND
(FRAE)
RED TEST
LEAO
TO TERMINAL
Figure l8
"see
your
manufacturer's
service
manuar
for
the
particular
motor
specification
-relative
to
piston
movement
with
timing
of
magneto."
Set
this
first.
Again,
be
certain
that
the
breaker
points
are
mnking
perfect
contact.
Refer
to
"High
Resistance
Test
in
primary
Circuit,,,
preceding.
After
wiring
hoolmp
is
made,
as
shown in
illustration preceding,
turn
selector
switch
to
position
No.2r
"Distributor
Resistancet',
and readscale
No.2.
Rotate
magneto
or distributor
in the
advance
direction.
It
x/ill be noted,
when
points
are
closed, that
the
meter
pointer
hand
will
be
in the
,rg6,i
block.
The
moment
that
the
breaker
points
start to
open,
the
meter
pointer
hand
will move
into
the
high
resistance
band.
In this
m:urner,
the
timing
can be
set in
relation
to
movement
of
the
piston.
on
magnetos,
such as
Fairbanks-Morse
or Kiekhaefer
type,
connect
the
small
red
test
lead
to the
exposed
primary
ground
terminal
and
the
black
lead
to
the
frame
or
ground.
See Fig. 18.
ARMATURE
GROUND
TEST
Figure
l9
T\rrn
selector
switch
to
position
No.
3,
.,Coil
Continuity,,.
Attach
small
black
test lead
to armature
shaft,
as
shown in ilustration
above,
and
use
small red
test
lead
to
probe
the
commutator
copper
divisions.
If the
pointer
hand
moves
across the
meter to
the right,
as ttre
divisions
are
contacted,
the
armafure
is
grounded
and must
be replaced
or
com-
mutator
must be
cut
down
and
mica
must
be undercut.
Meter
pointer
hand
should
not
move
during
this
test.
t7