Alternator Testing; Battery Care - Westerbeke 7.6 kw EDT Operator's Manual

. ALTERNATORS TESTING/TROUBLESHOOTING
TESTING THE EXCITATION CIRCUIT
1. Connect the positive
(+)
multhneter probe to the
excitation tenninal R on the alternator and the negative
(-) lead to ground.
2·.
'fum
the battery switch to the on position and hote
the multhneter reading. The reading should be 1.3 to
2.5 volts (see iIlustration) ..
TESTING THE
EXCITATION
CIRCUIT
OUTPUT TERMINAL·
3. ·Ifthe reading is between .75 and 1.1 volts, the
rotor field circuit probably is shorted or grounded.
4. If the reading is between 6.0 and 7.0 volts, the rotor
field circuit probably is open.
5. If no reading is obtained, an open exists in the
alternator-excitation lead or in the excitation circuit of
the regulator. Disconnect the lead from exc ternrlnal R.
Connect the positive multhneter probe to the excitation
lead and the negative multimeter probe to ground.
If the multhneter now indicates an approximate battery
voltage, the voltage regulator is defective and must be
replaced. If no voltage is indicated, check the
excitation circuit for loose or dirty connections or
damaged wiring.
OUTPUT TERMINAL
CHECKING THE SERVICE BATTERY
Check the.voltage of the service battery. this battery should
have a voltage between 13 and 14 volts when the engine is
running. If not, there is a problem in the service battery
. charging circuit. Troubleshoot the service battery charging
circuit by checking the wiring and connections, the soleuoid,
isolator" battery switch, and the battery itself.
When the problem has been solved and before the alternator
is back in operation, take the thne to tighten and clean the
'temrinal studs. Also clean the connecting ternninaIs from the
wiring harness.
ALTERNATOR REPAIR
If tests indicate a failed alternator, it will need to be disas-
sembled and repaired. Any good alternator service shop can
do the job.
NOTE:
WESTERBEKE'S Service Mwmal
has
detailed
instmetions for the disassembly and repair of their
standard alternators.
BATTERY CARE
The minimum recommended capacity of the battery used in
the engine's 12 volt DC control circuit is 600 - 900 Cold
Cranking Amps (CCA).
Review the manufacturer's reconunendations and then
establish· a systematic maintenance schedule for your
engine's starting batteries and house batteries.
• Monitor your voltmeter for proper charging during
engine operation.
• Check the electrolyte level and specific gravity with a
hydrometer. .
• Use. only distilled water to bring electrolytes to a proper
level.
• Make certain that battery cable connections are clean and
tight to the battery posts (and to your engine).
TESTING THE
EXCITATION
CIRCUIT
ENGINE
RUNNING
EXCITER
TERMINAL
R
Engines & Generators
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