Alternator Testing - Westerbeke 5.5 kw EDC 60 HZ Operator's Manual

ALTERNATORS TESTING/TROUBLESHOOTING
DESCRIPTION
50 AMP MITSUBISHI
ALTERNATOR
REFER TO THE WIRING
DIAGRAM IN THIS
MANUAL FOR ALL
WIRING CONNECTIONS
The following infonnation applies to the standard alternators
that are supplied with WESmRBEKE'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 (1(:'s), the electronic voltage
regulator is very compact and is mounted internally or on the
back of the alternator.
I! is desirable to test the charging system (alternator and
voltage regulator) nsing 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 alternators produce a rated output of 50 or 51 amps.
rated output is achieved at approximately 6000 alternator
rpm
at
an ambient temperatore of 75°P (23.8°C). The
altemators are designed to operate in an ambient temperatore
nmget>f'40°to'2i2"P-(40°1:Q iQO°C).
VOLTAGE REGULATOR
The integral voltage regulator is an electronic switching
device which senSeS 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 seini conductors and
thick-fihn 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 detennine if a problem
exists with the charging circuit or with the alternator. If it is
detennined that the alternator or voltage regulator is faulty,
have a qualified technician check it
A
WARNING:
A working alternator runs hot. A failed
alternator can become very hot. Do not touch the
alternator until if has cooled.
LOW BATTERY/FAULTY CIRCUIT
If the starter only moans or makes a clicking sound iIistead
of spinuing the engine to life it is likely a low battery or a
fanlty counection in, the starting circuit and not an alternator
problem.
PRELIMINARY INSPECTION
Before starting the actual alternator and voltage regulator,
testing the following checks are recommended.
1. Make certain your altemator is securely mounted,
2. Check the drive belts for proper tension. Replace the belt
if it is wom or glazed.
3. Check that
all
tenninals, connectors and plugs are clean
and tight. Loose or corrn<;led coruiections cause high
resistance and this conld 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 iIi the tests.
NOTE: An isolator with a diode, a solenoid, or a baltery
selector switch is usually mounted in the circuit to isolate
the batteries so the starting battery is not discharged along
with the house balteries.
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.
Engines & Generators
31