Westerbeke 29.0 EGED 60Hz Operator's Manual page 29

ALTERNATORS TESTING/TROUBLESHOOTING
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.
Mter the engine has run for a few minutes, measure the
starting battery voltage at the battery termimJls using a
multimeter set on DC volts.
a.
If the voltage is increasing toward 14 volts, the
alternator is working.
b. If the voltage remains around 12 volts, a problem
exists with either the alternator or the charging circuit;
continue with Steps 3 through
6i.
3. Turn off the engine. Inspect all wiring and connection.s. .
Ensure that the battery terminals and the engine ground'
connections are tight and clean
4.
If a battery selector switch is in the charging circuit,ensure
that it is on the ·correct battery.
5.
Check the battery voltage. If your battery is in good
condition the reading should be 12 to 13 volts.
6. Load test the battery if there is a possible issue with
weak/faulty cell.
MEASURING
BATTERY VOLTAGE
TESTING THE OUTPUT CIRCUIT
1.
Connect the positive probe to the output terminal
B
and
connect the negative probe to ground.
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 same measurement, the negative probe to
ground,
~he
positive probe to B with 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 the voltage output
is 13-14 volts, .. then the alternator is OK.
TESTING THE OUTPUT
CIRCUIT
ENGINE RUNNING
Engines &. Generators
23