Installation manual
ALTERNATORS
TESTlNG/TROUBLESHOOTlNG
PRELIMINARY
INSPECTION
Before starting the
actual
alternator
and
voltage
regulator,
testing
the
following
checks
are
recommended.
1:
Make certiun
your
alternator
is
securely
mounted.
2.
Check
the
drive
belt
for
proper
tension.
Replace
the
belt
if it
is
worn
or
glazed.
3. Check that all
terminals,
connectors
and
plugs
are
clean
and
tight.
loose
or
corroded
connections
cause
high
resistance
and
this
could
cause
overcharging,
undercharging
or
damage
to
the
charging
system.
Badly
corroded battery
cables
could
prevent
the
battery
from
reaching a
fully
charged
condition.
4. Check the
condition
of the battery
and
charge
if
necessary.
A
low
or
discharged
battery
may
cause false
or
misleading
readings
on
Ihe
in-vessel
tests.
NOTE:
An isolator with a
diode,
a sole/wid, or a battery
selector switch
is
usually nwunted in
the
circuit
to
isolate
the batteries
so
the
starting battery is not discharged
along with the hause batteries.
If
the isolator
is
c!ul.rging
the starting battery but not the house
battery,
the
alternator
is
Ok
and
the problem
is
in
the
battery
charging
circuit.
TESTING
THE
ALTERNATOR
A
CAUTION:
Before
starting
the
engine
make
certain
that
everyone
is
clear
of
moving
parts!
Keep
away
from
sheaves
and
belts
during
test
procedures.
1. Start the engine.
2. After
Ihe
engine
has run
for
a
few
minutes,
measure the
starting battery voltage
at
Ihe
battery
terminals
using a
multimeter
set
on
DC
volts.
a.
If
Ihe
voltage
is
increasing toward
14
volts,
Ihe
alternator is
working;
omit
Steps 3 through 8 and
go
directly
to
"Checking
Ihe
Servic~
Battery".
b.
If
Ihe
voltage remains
around
12
volts,
a problem
exists
wilh
eilher
Ihe
alternator or
Ihe
charging
circuit;
continue
with
Steps 31hrough
8.
MEASURING
BATTERY
VOLTAGE
ENGINE
RUNNING
3.
111m
off the engine.
Inspect
all
wiring
and
connections.
Ensure
Ihat
the
battery
terminals
and
the engine ground
connections
are
tight
and
clean.
4.
If
a
battery
selector
switch
is
in
the charging circuit,
ensure
Ihat
it is
on
Ihe
correct
setting.
5.
111m
on
the ignition switch, but
do
not
start
the
engine.
6.
Check
the
battery
voltage.
If
Ihe
battery
is
in good
condition,
Ihe
reading
should
be
12
to
13
volts.
Testing
The
Output
Circuit
MEASURING
BATTERY
VOLTAGE
(IGNITION
ON
ENGINE
OFF)
1.
Connect the positive probe
to
the output terminal
Band
connect the negative probe
to
the gronnd terminal E
on
the
alternator.
2. Wiggle the engine wiring harness while observing the
voltmeter. The meter should indicate the approximate
battery voltage,
and
should
not
vary.
If
no
reading
is
obtained,
or
if the reading varies, check the alternator
output circuit for loose or
dirty
connections or
damaged
wiring.
3. Start the engine.
4.
Repeat the
sarne
measurement, the negative probe
to
E,
the positive probe
to
B wilh the engine running. The
voltage reading should be between
13.5
and
14.5
volts.
If
your alternator is over
or
under-charging, have it
repaired at a reliable service shop.
5. If the previous test
reads
only
battery voltage at
terminal B use the meter
to
measure the
DC
excitation
terminal. If
12
volts
is
not present at exciter terminal
R,
inspect the wiring for breaks and poor connections.
Jump
12
volts
from
a
12
volt source (such
as
the
battery)
and
operate
the
alternator.
If
voltage output
is
13-14
volts,
then
Ihe
alternator
is
OK.
"'IIY'"
WESTERBEKE
Eng!ne~
_~_
Gener~t~rs
32