Alternator Testing - Westerbeke 7.6 EGTD 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. ·
f1DRED
t14PURPLE
ALTEBIATOR
TROUBLESHOOTING
A
WARNING:
A failed altemator
t:a11
become very
hot. Do not touch until the alternator has 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 tbe engine make certain
that everyone Is clear of moving parts! Keep away from
sheaves and belts during test procedures.
A
WARNING:
Multimeters and DC Cln:ults:
tlC_aoJI.ACJ:JIJHIItsJDJLtliiJJJiliXttd_loJJSfher in.madne
applications. Always disconnect shore power cords,
iss/ate DC and AC converters and shut down generators
before pedonning DC testing. No AC
tests
should be
made without proper knowledge of AC cirt:lllts.
Testing the Alternator
1. Start the
Engine.
2. After a few minutes of running measure the starting bat-
tery voltage
at
the battery tennin.als using
a
multi-meter
set on DC volts.
The voltage should be increasing toward
14 volts. If
it is,
the alternator is working. Thm to Step 4.
TESnNG THE STARTING
. BATTERY· 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. Tum 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 cin:uit, never shut
off
the engine
battery
switch when the engine
Is
running!
b. ,If a battery selector switch is in the charging circuit,
ensure that it is on the correct setting.
c.. Thm 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.
TESTIN&lHE
STARI'IIG
BATJERY
ENGINE OFF
am
0
.MULTIMETER
COM
:STARTING BATIERY
l..,..,.lWESTERBEKE
.f
E~qines
& Generators
29