Alternator Testing - Westerbeke 5.5 EGCD Operator's Manual

ALTERNATOR TESTING
DESCRIPTION
The charging system consists of an alternator with a voltage
regulator, an engine DC wiring
harness,
a mounted DC cir-
cuit breaker and a battery with connecting cables. Because of
the use.of integrated circuits (IC's) the electronic voltage reg-
ulator is very compact and is mounted internally or on the
back of the alternator. ·
110 RED
B+OUTPUT
50 AMP
ALTERNATOR
To starter motor ,
114 PURPLE
TROUBLESHOOTING
A
WARNING:
A failed alternator can become very
hot. Do not touch until the alternator bas cooled down.
This troubleshooting section is 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 bad, it is
best to have a qualified technician check it out.
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 isolate the batteries so the service
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 charging circuit and not with the alternator.
A
WARNING:
Before starting the engine make certain
that everyone is clear of moving
parts!
Keep away from
sheaves and belts during
test
procedures.
A
WARNING:
Molt/meters and DC Circuits:
-. .D.C..and_jJ_C.J:Jn:u.lt$JLI'JtfJ1lmJJJJix.IHI.JD.get/ulr ln.
marine
applications. Always disconnect sllore power cords,
Isolate DC and AC converter.s and shut down generators
before perfonning DC testing.
No
AC tests should be
made without proper knowledge of AC clrt:lllts.
Testing the Alternator
1. Start the Engine.
2. After a few minutes of running measure the starting bat-
tery voltage at the battery texminals using
a
multi-meter
set on DC volts.
The voltage should be increasing toward 14
volts. If it is,
the alternator is working. Thrn to Step 4.
TESnNG THE STARTING
BArnRY ·ALTERNATOR
(ENGINE RUNNING}
3. If the starting battery voltage remains around 12 volts
after
the
engine is started and run for a few minutes, a
problem exists with
the
alternator or the charging circuit.
a. Turn off the engine. Inspect all wiring and connections.
Ensure that the battery terminals and the engine ground
connections are tight and clean.
A
CADnON:
To avoid damage to the battery
charging circuit, never shut off the engine battery
switch when the engine is mnnlng!
b. ,If a battery selector switch is.in the charging circuit,
ensure
that
it is on
the
correct setting.
c:. Thrn on the ignition switch, but do not start the engine.
d. Check the battery voltage. If your battery is in good
condition the reading should be 12 to .13 volts.
TESnNG THE STARnNG
BATTERY • ENGINE OFF
MULTtMETER
,STARTING BA11ERY
En!:Jines & Generators
29