Paragraph
1 02
Fig. 1()()-V/ew showing terminals and test hole on
Delco-Remy alternator.
within 10 amperes of rated output,
renew regulator and check field (rotor)
winding as outlined
in
paragraph
102.
If output is still not within 10 amperes
of rated output, disassemble alternator
and check field winding, diode trio, rec·
tifier bridge and stator as outlined in
paragraph
102.
If
alternator fails to start charging at
all, there may be an open circuit in wir·
ing to
No.
1
terminal of alternator.
Voltage must be present at this terminal
to provide initial excitation of field wind·
ing to
start
alternator charging.
A
quick
field check for an open excitation circuit
is to momentarily place a jumper wire
between alternator
"BAT"
terminal and
No.
1
terminal with engine running. If
alternator starts charging, when it
would not without jumper, an open ex·
citation diode (located in wiring
harness), oil pressure switch (diesel
models), or ignition switch (gasoline
models) is indicated.
102. OVERHAUL. To
disassemble the
alternator, fU"St scribe matching marks
(M-Fig.
101)
on the two frame halves
(4
and
16),
then remove the four through·
bolts. Pry frame apart with a screwdriver
42
Starter
Solenoid
Fig. 99-Connecr test
am
meter and voltmeter In circuit
Ill
''BAT''
terminal as shown
to
check output of Delco
Remy alternator. Refer
to
text.
Fig. 101-Exp/oded view of Delco-Remy alternator
with Internal mounted solid-state regulator. Note
match marks (M) on end frames.
I.
Pulley nul
2.
Wather
3.
Spacer
(oulSide
drave
end)
4.
Drive end frame
5. Grease
alinger
6. Ball
bearing
7.
Spacer
(inside dnvo
end
I
8
.
Beanng retamer
•
9.
Bridge
rectifier
10.
Otode l.rlo
11
Capaettor
12.
Stator
13.
Rotor
14.
Bru1h holdar
16.
Solid·state re��U�ator
16.
Slip ring end frame
17.
Bearing
&
aeul usy
between stator frame
(12)
and drive end
frame
(4).
Stator assembly
(12)
must re
main with slip ring end frame
(16)
when
unit is separated.
NOTE: When frames are separated,
brushes will contact rotor shaft at bearing
area.
B
r
u
s
h
e
s MUST be cleaned of lubricant
If they are to be reused.
Clamp the iron rotor
(13)
in a protected
vise only tight enough to permit loosen
ing of pulley nut
(1).
Rotor end frame
can
be separated after pulley and fan are
removed. Check bearing surface of rotor
shaft for visible wear or scoring. Ex
amine slip ring surface for scoring or
wear, and rotor winding for overheating
or
other damage. Check rotor for ground
ed, shorted or open circuits using an
ohmmeter as follows:
MASSEY -FERGUSON
Fig. 102-Removed rotor assembly showing test
points to
be
used when checking for grounds,
shorts end opens.
Fig. 103-Test points for brush holder, refer to
text.
Refer to Fig.
102
and touch the ohm
meter probes to points
(1-2)
and
(1-3);
a
reading near zero will indicate a short
circuit to ground. Touch ohmmeter
probes to the slip rings
(2-3);
reading
should be
5.3-5.9
ohms.
A
higher reading
will indicate an open circuit and a lower
reading will indicate an internal short.
If windings
are
satisfactory, mount rotor
in a lathe and check runout at slip rings
using a dial indicator. Runout should not
exceed
0.0
5
mm
(0.002
inch). Slip ring
surfaces can be trued if runout is ex
cessive or if surfaces are scored. Finish
with
400
grit or finer polishing cloth un
til scratches or machine marks
are
removed.
Before removing stator, brushes or
diode trio, refer to Fig.
103
and check for
grounds between points
A
and C and B
to C with an ohmmeter using the lowest
range scale. Then reverse the lead con
nections. If both
A
to C readings or both
B to C readings are the same, the
brushes may be grounded because of
defective insulating washer and sleeve
at the two screws. If the screw assembly
is not damaged or grounded, the
regulator is defective.
To
test the diode trio, first remove the
stator. Then remove the diode trio,
noting the insulator positions. With an