Terminal; Field Coil; Brushes And Brush Lead Wire; Brush Spring Tension - Datsun 620 Series 1977 Service Manual

CLEANING AND
INSPECTION
Clean all disassembled parts but do
not
use
grease
dissolving solvents for
cleaning overrunning
clutch annature
assembly
magnetic
switch
assembly
and field coils
since such
a
solvent
would dissolve grease
packed
in c1u tch
mechanism and would damage coils
or
other insulators
Check them for
excessive damage
or wear
and
replace
if
necessary
TERMINAL
Check
terminal for
damage
and
wear
and replace magnetic switch
assembly if
necessary
FIELD COIL
Check field coil for insulation If
the insulation of coil is
damaged
or
worn
it
should be
replaced
Testing field coil
for
continuity
Connect the
probe
of
a
circuit
tester
or an
ohmmeter
to
field coil
positive
terminal and
positive
brush
holder
If
tester
shows
no
continuity field
circuit
or
coil is open
EE016
Fig EE I2 Testing field
coil
for continuity
TestIng
field coD for ground
Place
one
probe
of
circuit tester
onto yoke
and the other
onto
field
coil lead
positive
tenninal
If very little resistance
is
read field
coil is grounded
Engine Electrical
System
EE017
Fig
EE I3
Testing rU ld coil
for
ground
BRUSHES AND BRUSH
LEAD WIRE
Check the surface condition of
brush
contact
and
wear
of brush If
a
loose
contact is
found
it
should be
replaced
Ifbrush is
worn so
that its
length is
less than 12
mm
0 472 in
replace
Check
the
connection
of lead
clip
and lead
wire
o
@
EE 8
Check brush holders and
spring cUp
to
see
if
they
are
not deformed
or
bent and will
properly
hold brushes
against
the
commutator
If brushes
or
brush holders
are
dirty they should
be
cleaned
BRUSH
SPRING TENSION
Check brush
spring
tension
by
a
spring
scale
as
shown
in
Figure
EE 13
The
reading
should be
1
6 kg
3 5
Ib
Replace spring if tension
is lower than
I 4
kg
3 1 Ib
ARMATURE ASSEMBLY
Check external
appearance
of
armature
and
commutator
1
Inspect
commutator
If
the
sur
face of
commutator
is rough
it must
be sanded lightly with
a
No 500
emery
cloth If the
depth
of
insulating
mica is less than 0 2
mm
0 0079
in
from
commutator
surface
insulating
mica
should also be undercut
so
that
its
depth
is 0 5 to
0 8
mm
0 01 97
to
0 0315
in
The
wear
limit of
commutator
dia
meter is 2
mm
0 0787 in If the
diameter of
cammu
tator is less than
31
mm
1
220
in
replace annature
assembly
EE018
Fig EE 14
Inspecting
brush
spring
tension