ALTERNATOR/REGULATOR
SERVICE
The voltage reading
for
a
properly
operating alternator
should be between
13.5
and
14.5 volts. If your alternator
is
over- or undercharging,
have
it
repaired at a reliable service
shop, or continue
with
the
following tests.
NOTE:
Before removing the alternator for
repair,
use your
voltmeter to ensure that
12
volts
DC excitation is present
at
· the R (EXC) termitzal
if
the
previous tesi showed only battery
voltage at the
B output
terminal.
+
Output
Test
1. Disconnect
the
battery
ground
cable.
2. Disconnect
the
wire
from
terminal B
on
the
alternator
and
connect
an
ammeter between B
and
this wire.
3. Connect a voltmeter
between
terminal
B (+)and ground(-).
4. Connect to
the
P terminal.
5.
Reconnect
the
battery
ground
cable
to
the(-)
terminal.
The
voltmeter should itulicate
the
battery voltage.
6. Connect B+
to
the
R
terminal
(regulator).
7.
Start the engine.
8. Tum on 12 volt accessories equaling
the
amperage output
of the alternator, accelerate
the
engine
to
the specified
speed
(2000
to
3000
rpm)
and
measure the output cur-
rent. The output current should be close to the alterna-
tor's maximum ouput.
Output
Current
1300
rpm
2500rpm
5000
rpm
Hot
16
amp
41amp
48amp
Cold
24amp
50
amp
NOTE:
rpm is
that
of
the
alternator.
The pulley ratio
(alternator vs
cratlk
pulley)· is 1.78 to 1; all readings
are
at i 3.5 volts.
DISASSEMBLY
1.
After removing
the
three assembly through-bolts,
msert
a
screwdriver
between
the
front
bracket and stator. While
prying it, remove
the
front
bracket
and
rotor.
--
..
NOTE:
If
the
screwdriver
is
inserted too
deep,
the
stator
coil
might
be
damaged.
2.
Hold
the
rotor
in
a
vise
and
remove
the
pulley
nut.
Then
remove
the
pulley,
fan,
spacer
and
seal.
Next,
remove
the
rotor
from
the
front
bracket
and
remove
the
seal.
3.
Unsolder
the
rectifierfrom
the
stator
coil
lead
wires
and
remove
the
stator
assembly.
NOTE:
Make
sure
that
the
solder is removed
quickly
(in
less
than
five
seconds).
If
a
diode
is heated
to
more
than
150°C
(310°F),
it
might
be
damaged.
4.
Remove
the condenser
from
terminal
B.
5.
Unsolder
the
plates
B
and
L
from
the rectifier assembly.
6.
Remove
the
mounting
screw
and
B terminal
bolt
and
remove
the
electronic
voltage
regulator and
brush
holder.
The
regulator
and
brush
holder
cannot be sepearated.
7.
Remove
the rectifier
assembly.
8.
Brush
and
brush
spring
replacement:
When
only
a
brush
or
brush
spring
is
to
be
replaced,
it
can
be
replaced
without
removing
the
stator,
etc.
With
the
brush
holder
assembly
removed,
unsolder
the
pigtail
of
the
brush.
NOTE:
If
the
terminals L
and
B
of
the
rectifier
assembly
are
bent,
damage
might
result
to
the
rectifier.
Therefore,
the
plates B and L should
be
gemly
bent
at
the
center.
RECTIFIER
ASSEMBLY
REGULATOR&
BRUSH
HOLDER
Engines & Generators
74
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