Alternator Testing; Voltage Regulator - Westerbeke 8.0KW-60Hz ENDT Operator's Manual

ALTERNATORS TESTING/TROUBLESHOOTING
4#100RANGEB
TO STARTER SOLENOID
DESCRIPTION
50 AMP MITSUBISHI
ALTERNATOR
CASE GROUND
REFER TO THE WIRING
DIAGRAM IN THIS
MANUAL FOR AU
WIRING CONNECTIONS
The following infonnation applies to the standard alternators
that are supplied with WESTERBEKE'S Engines and
Generators.
ELECTRICAL CHARGING CIRCUIT
The charging system consists of an alternator with a voltage
regulator, an engine DC wiring harness, a mounted DC
circuit breaker and a battery with connecting cables. Because
of the use of integrated circuits
(I~'s),
the electronic voltage
regulator is very compact and is mounted internally or on the
back of the alternator.
It is desirable to test the charging system (alternator and
voltage regulator) using the wiring harness and electrical
loads that are
a
permanent part of the system and will then
provide the technician with an operational test of the
charging system as well as the major components of the
electrical system.
ALTERNATOR DESCRIPTION
The stator is connected to a three-phase. full-wave bridge
rectifier package which contains six diodes. The bridge
converts the AC generated in the stator to a DC output for
battery charging and accessories,
Power to the regulator and the field of the integral regulator
alternator is provided by the field diode (or diode trio)
package contained in the alternator.
These altemators produce a rated output of 50 or 51 amps.
rated output is achieved at approximately 6000 alternator
rpm at an ambient temperature of 75°P (23.8°C). The
alternators are designed
to
operate in an ambient temperature
range uf40° to£!£"F-( 4eo,1O leO°C).
VOLTAGE REGULATOR
The integral VOltage regulator is an electronic switching
device which
sens~s
the system voltage level and switches
the voltage applied to the field in order to maintain a proper
system voltage.
The regulator design utilizes all-silicon semi conductors and
thick-film assembly techniques. After the voltage
has
been
adjusted to the proper regulating valve, the entire circuit is
encapsulated to protect the circuit and the components from
possible damage due to handling or vibration.
ALTERNATOR TROUBLESHOOTING
Use this troubleshooting section 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 faulty,
have a qualified technician check it.
A
WARNING:
A working alternator runs bot. A failed
alternator can become very bot. Do not touch the
alternator until if bas cooled.
LOW BATTERY/FAULTY CIRCUIT
If the starter only moans or makes a clicking sound instead
of spinning the engine to life it is likely a low battery or a
faulty connection in. the starting circuit and not an altemator
problem.
PRELIMINARY INSPECTION
Before starting the actual alternator and voltage regulator,
testing the following checks are recommended.
1. Make certain your alternator is securely mounted.
2. Check the drive belts for proper tension. Replace the belt
if it is worn or glazed.
3. Check that all tenninals, connectors and plugs are clean
and tight Loose or
corr~ed
connections cause high
resistance and this could cause overcharging,
undercharging or damage to the charging system. Badly
corroded battery cables could prevent the battery from
reaching a fully charged condition.
4. Check the condition of the battery and charge if necessary.
A low or discharged battery may cause false or misleading
readings in the tests.
NOTE:
An isolator with a diode, a soleooid, or a battery
selector switch is usually mounted in the circuit
to
isolate
the batteries so the starting battery is oot discharged along
with
the
house batteries.
If
the isolator is charging the
starting battery but oot the house battery, the altemator is
OK
and
the problem
is
in the battery charging circuit.
Engines & Generators
32