Westerbeke 5.5 kw EDC 60 HZ Operator's Manual page 42

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.
~tart
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
alternator is working.
b.
If
the voltage remains around 12 volts, a problem
exists with either the a1termitor or the charging circuit;
continue with Steps 3 through 6,
MEASURING
BATTERY VOLTAGE
(ENGINE RUNNING)
3. Thm off the engine. lospect all wiring and connections.
Ensure that the battery tenninals and the engine ground
connections are tight and clean
4. If a battery selector switch is in the charging circuit,ensure
t\1at it is on the correct setting. .
5. Check the battery voltage. If your hattery is in good
condition the reading should be 12 to 13 volts ..
MEASURING
BATTERY VOLTAGE
ENGINE OFF)
TESTING THE
nllTDIIT
1. Connect the positive probe to the output tenninal B and
connect the negative probe to ground.
2. Wiggle the engine wiring harness while observing the
voltmeter. The rtleter should indicate the approximate
battery voltage, and shonld not vary. If no reading is
obtained, or if the reading varies, check the alternator
outpnt circuit for loose or
dirty
connections or
damaged wiring.
3. Start the engine.
4. Repeat the same measurement, the negative probe to
ground, the 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 repai):ed at a reliable service shop.
5.
If
the previous test reads ouly battery voltage at
tenninal B, use the meter to measure the DC excitation
tenninill. If 12 volts is not pre&ent at exciter tenninal R,
inspect the wiring for breaks aiJd 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 .. then the alternatoris OK
TESTING THE OUTPUT
CIRCUIT ENGINE RUNNING
#100RANGEB
TO STARTER
OUL,tNUIU
#16 VlliLET R
TO K-3 RELAY
/TERMINALR
Engines & Generators
32