Dc Electrical System (Alternator) - Westerbeke 11.5KW-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 barness, a
mounted DC circuit breaker and a battery with connecting
cables. Because of the use of integrated circuits (IC's), the
electronic voltage regulator is very compact and is mounted
internally or on the back of the alternator.
II.
GRAY=='j~~;;;:
AMP ALTERNATOR
SEE WIRING DfAGRAM
FOR WIRE CONNECTIONS .
TO OPT/ONAL ALTERNATORS.
ALTERNATOR TROUBLESHpOTING
Use this troubleshooting section to determine 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 charges 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 iso-
late the batteries so the starting battery is not discharged along
with the service battery. If the alternator
is
charging
the
start-
ing battery but not the service battery, the problem is in the
service battery's charging circuit and not with the alternator.
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.
A
WARNING:
When testing with a
multi meter:
DC and AC circuits
are
often mixed together In marine
applications. Always disconnect
a
shore power cord,
isolate DC and AC converters, and shut down the engine
before performing DC testing. No AC tests should be
made without
a
proper knowledge of AC Circuits.
1. Start the engine.
2. After the engine has run for a few minutes, measure the
starting battery voltage at the battery terminals 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.
h.If the voltage remains around 12 volts, a problem
exists with either the alternator or the charging circuit;
continue with Steps 3 through 8.
CilMiJ
MULTIMETER--->-t0
TESTING THE STARTING
BAnERY/ALTERNATOR
(ENGINE RUNNING)
COM
e
-=GROUND
STA,RTING BATTERY
3. Thrn off the engine. Inspect all wiring and connections.
Ensure that the battery tenninals 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 the engIne
is
running!
4. If a battery selector switch is in the charging circuit,
ensure that it is on the correct setting.
S. Tum on the ignition switch, but do not start the engine.
6. Check the battery voltage. If
the battery is in good
condition, the reading should be 12 to 13 volts.
TESTING THE
ALTERNATOR VOLTAGE
(IGNITION ON - ENGINE OFF)
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WESTERBEICE
Engines & Generators
62
GROUND