Dc Electrical System; Alternator Troubleshooting - Westerbeke 8.0KW-60Hz Service Manual

DC ELECTRICAL SYSTEM
ALTERNATOR
The charging system consists of a DC belt driven alternator
with a voltage regulator, an engine DC wiring harness, a
mounted DC circuit breaker and a battery with connecting
cables. Because of the use of integrated circuits (Ie's), the
electronic voltage regulator is very compact and is mounted
internally or on the back of the alternator.
'14 BROWN
TO TB2-4
'14 VIOlET
1. Start the engine.
2. After the engine has run for a few minutes, measure the
starting battery voltage at the battery tenninals using a
multimeter set on DC volts.
a. If the voltage is increasing toward 14 volts, the alterna-
tor is working; omit Steps 3 through 8 and go directly
to "Checking the Service Battery~' on the -next page.
b. If the voltage remains around 12 volts, a problem
exists with either the alternator or the charging circuit;
continue with Steps 3 through 8.
(gQJ
MUlTIMETER~.
--1' 1 0
COM
TO FUEL SOLENOIO,
LIFT PUMP ANO
. OISTRIBUTOR
AMP ALTERNATOR
SEE WIRING DIAGRAM
..... ....""
_~"
FOR WIRE CONNECTIONS.
GROUND
ALTERNATOR TROUBLESHOOTING
A
WARNING:
A failed alternator can become very
hot.
Do
not touch until the alternator has cooled down.
Use this troubleshooting section to detennine if a problem
exists with the charging circuit or with the alternator. If it is
determined that the alternator or voltage regulator is faulty,
have a qualified technician check it.
The alternator charging circuit chaIges the starting battery
and the service battery. An isolator with a diode, a solenoid
or a battery selector switch is usually mounted in the circuit
to isolate the batteries so the starting battery is not discharged
along with the service battery. If the alternator is charging the
starting battery but not the service battery, the problem is in
the service battery's charging circuit and not with the alterna-
tor.
Testing the Alternator
A
CAUTION:
Before starting the engine make certain
that
tweryone
Is
clear of moving partsl Keep awa¥ from
sheaves and belts during test procedures.
A
WARNING:
When testing with
a
multimeter:
DC and AC circuits are often mixed together in marine
applications. A/rIays disconnect
a
shore power cord,
fsD/ate DC and AC convertelS, and shut doWn the engine
befDte
perftmnlng DC testing. No AC
tests
should be
made without
a
proper knowledge of AC circuits.
TESTING THE STARTING
BAmRY/ALTERNATOR
(ENGINE RUNNING)
e
-=GROUND
STARTING BATTERY
3. Turn off the engine. Inspect all wiring and connections.
Ensure that the battery terminals and the engine ground
connections are tight and clean.
A
CAUTION:
To avoid damage to the battery
charging circuit, never shut off the engine battery
switch when tlie engine is running!
4. If a battery selector switch is in the charging circuit,
ensure that it is on the correct setting.
5. TUrn on the ignition switch, but do not start the engine.
6. Check the battery voltage. If the battery is in good condi-
tion, the reading should be 12 to 13 volts.
TESTING THE
ALTERNATOR VOLTAGE
~
o
_ ... k---;,MUlTIMETER
(IGNITION ON • ENGINE OFF)
~l:;~:ii~
~b:::::::::::=S~l;ART;:ING
BATTERY
Engines & Generators
- GROUND
31