Dc Electrical System - Westerbeke 55A FOUR Operator's Manual

DC ELECTRICAL SYSTEM
DESCRIPTION
The charging system consists of an alternator with a mounted
voltage regulator, an engine DC wiring harness, a mounted
DC circuit breaker, and a battery and connection wires.
Because of the use of integrated circuits (IC's) the electronic
voltage regulator is very compact and is mounted internally
or on the back of the alternator.
Alternator Troubleshooting
If you suspect that the alternator is not producing enough
voltage to charge the engine's battery, check the following:
A
WARNING:
A failed alternator can become very
hot. 00 not touch until the alternator has cooled down.
o
Make certain your alternator is securely mounted.
o
Check the drive belts for proper tension.
A.
WARNING:
Before starting the engine make certain
that everyone is clear of moving parts! Keep away from
sheaves and belts during test procedures.
5. Start the engine.
6. The voltage reading for a properly operating alternator
should be between 13.5 and 14.5 volts. If your alternator
is over- or undercharging, have it repaired at a reliable
service shop.
NOTE:
Before removing the alternator for repair, use your
voltmeter to ensure that
i
2 volts DC excitation is present at
the R terminal
if
the previous test showed only battery volt-
age at the B output terminal.
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o
Inspect for loose or disconnected wires at the alternator.
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NOTE:
An isolator with a diode, a solenoid, or a battery
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selector switch is usually mounted in the circuit to isolate the
batteries so the starting battery is not discharged along with
the house batteries. If the isolator is charging the starting
battery but not the house battery, the alternator is OK and
the problem is in the battery charging circuit.
A
WARNING:
Shut off the engine battery switch or
disconnect from the battery when working on the engine
electrical system.
Checking for Proper Voltage
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TYPICAL 51 AMP
ALTERNATOR CONNECTIONS
~~~~=f10RED
If you suspect the alternator has failed perform the following
tests with the engine off:
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RED==f==~~iS-+
......
1. Using a voltmeter, connect the voltmeter red wire clip to
the output terminal B+.
2. Connect the voltmeter negative wire to any ground on the
engine .
. 3. Check the battery voltage. It should read 12 to 12 volts.
4. Check the voltage between the alternator (+) positive ter-
minal B and any engine ground. If the circuit is good, the
voltage at the alternator should be the same as the battery
(unless there's an isolator in the circuit, then the reading
would be zero).
A
CAUTION:
To avoid damage
to
the battery charging
circuit, never shut off the engine battery switch when
the engine is running!
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WESIERBEKE
I
Engines & Generators
18
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OPTIONAL 72 AMP ,
ALTERNATOR CONNECTIONS