70
V. ELECTRICAL
I. Checkin/1, carbon brushes
Check
the bru,hes
and
springs for conditio11 Brushes
that are worn
or
pilled
badly,
or
those which
do
not
aligit with the
commutator
bars
should be replaced with
new ones, Discard the springs
if
they are weak
so
that
the brushes unable
to
rest on
tl1e
commutator.
I-
Carbon brush length
I
mm(in.)
Brush spring tension
gr
am
'Z.
('leanmg commutator
-
-~
Standard
value Repair
li111it
11
-
125
5 (0.020)
(0,433-0.492)
max.
495 605
Sand
off
all burrs, copper
dust
or
uny
other
foreign
particles with a fine emery
clotlt
Wip<:
it clean before
iosrnllation..
3.
Checking field coil for
continuity
Check fo,
continuity
between
U,e
brushes
connected
to
the field coil and starting
motor
cable.
lf
there is
no
continuity,
it
is a reliable indication
that
the field coil
h:is
an
open
circulL
4. Checking armature
coil
for
continuity
A shorted
or
grounded armamre would
affect
the
proper
operation
of
U,e
starting motor. The armature is tested
electricolly for ground
by
placing
one
test
prohc
oil
the
tamina
led
cort
and
the
ol..her
on
the
commutalOr
bars.
If
there
is continuily.
the
::lrmature
is
grounded
Starting magnetic switch
TI1
e s
tarlin
g
mo
to
r d
ra
\V
S a large
amount
of
current as hi
gh
as
I
OOA
when
cr;1,n
king
the
Crlg.ine.
The electromagnetic swicch
serves lhe purpose o f remot
ely
switchmg
on
and
off
t
he
s
tar
ti
ng
moror.
- -
A
~·
-"
\
':
.
/,..
.,,
.
..
\ ' . /
.,
..
,~
-
,,-<
I-
.
.........
__
.:
.
•
1'
41
"-
• I .
r'
vt
,1
.
I '
·::.1
-·
~,
Fig.
5-23
(I)
Carbon brush
(2)
Brush spring
(3)
Commutator
.,...,.
__
_..
Fig.
S-24
Checking
stator
coil
Fig.
5-25
Check
in
g a
rma
tu
re
<.:o
il
m--
m -
:~:
..
·
__
....
·1 '
(Ii
~1·
.1
1
--~~-
-
, _
__
.
Fig. 5
26
(I)
Stopp<,-r
(2) Slapper holder
(3)
Washer
(4
) Roller A
(5) Contact
s'J)ring
(6)
Flat
washer
(7) Plunger holde,-
(8)
i,-
shaft
(9)
PIU!l#f
(II)
'
I
ll)
/
... ...... (
1)
;
__
-(
Ut
i
ll
)
(I
0) Cbntact bolt
(I
1)
case
(12) Contact plate
(1
3)
Yoke
(14)
Chi\
bobbin
(l
5) Coil
oo
mp!ete
(16)
Remrn spnng
(17) Body
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