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CHARGING SYSTEM
ENGINE ELECTRICAL16-11
11.Increase the engine speed to 2,500 r/min.
12.Read the value displayed on the voltmeter when
the current output by the alternator becomes 10 A
or less.
13.If the voltage reading conforms to the value in the
voltage regulation table, then the voltage regulator
is operating normally.
If the voltage is outside the standard value, there
is a malfunction of the voltage regulator or the
alternator (Refer to the following table).14.After the test, lower the engine speed to idle.
15.Turn the ignition switch to the "LOCK" (OFF)
position.
16.Disconnect the engine tachometer or diagnostic
tool .
17.Disconnect the negative battery cable.
18.Disconnect the ammeter and voltmeter.
19.Connect the negative battery cable.
20.Run the engine for 10 minutes at an idle.
VOLTAGE REGULATION TABLE
WAVE PATTERN CHECK USING AN
OSCILLOSCOPE
M1161001200180.
MEASUREMENT METHOD
Connect the oscilloscope special patterns pick-up to the
alternator "B" terminal.
.
STANDARD WAVEFORM
INSPECTION TERMINAL VOLTAGE REGULATOR
AMBIENT TEMPERATURE [
C
(
F)]STANDARD VALUE (V)
Te r m i n a l " S "
20 (4)14.2 15.4
20 (68) 13.9
14.9
60 (140) 13.4
14.5
80 (176) 13.1
14.2
Observation Conditions
FUNCTION SPECIAL PATTERNS
Pattern height Variable
Variable knob Adjust while viewing the wave
pattern
Pattern selector Raster
Engine revolutions Curb idle speed
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CHARGING SYSTEM
ENGINE ELECTRICAL16-12
NOTE: The voltage waveform of the alternator "B" terminal can
undulate as shown at left. This waveform is produced when the
regulator operates according to fluctuations in the alternator
load (current), and is normal for the alternator.
If the ripple height is abnormally high (approximately 2 V or
more during idling), the wires between the alternator "B" termi-
nal and the battery have broken due to fuse blowing, etc. The
alternator is usually operating properly.
.
ABNORMAL WAVEFORMS EXAMPLES
NOTE: The size of the waveform patterns can differ greatly,
depending on the adjustment of the variable knob on the oscil-
loscope.
NOTE: Identification of abnormal waveforms is easier when
there is a large output current (regulator is not operating).
(Waveforms can be observed when the headlights are illumi-
nated.)
NOTE: Check the conditions of the alternator malfunction light
(illuminated/not illuminated) also, and carry out a total check.
ABNORMAL WAVEFORMS
Example 1
PROBABLE CAUSE: Open circuit in diode
Page 990 of 1500
CHARGING SYSTEM
ENGINE ELECTRICAL16-13
Example 2
PROBABLE CAUSE: Short-circuit in diode
Example 3
PROBABLE CAUSE: Open circuit in stator coil
Example 4
PROBABLE CAUSE: Short-circuit in stator coil
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CHARGING SYSTEM
ENGINE ELECTRICAL16-17
ASSEMBLY SERVICE POINTS
.
>>A<< REGULATOR ASSEMBLY INSTALLATION
After installing the regulator assembly, insert a wire through the
hole provided on the rear bracket while pressing down on the
brush, and secure the brush.
NOTE: By inserting a wire, the brush will be secured in place,
and the installation of the rotor will be easier.
.
>>B<< ROTOR ASSEMBLY INSTALLATION
After installing the rotor, remove the wire used to secure the
brush.
INSPECTIONM1161001700099.
ROTOR CHECK
1. Check the continuity between the slip rings of the field coil. If
the resistance value is not within the standard value, replace
the rotor.
Standard value: approximately 2
5
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CHARGING SYSTEM
ENGINE ELECTRICAL16-18
2. Check the continuity between the slip ring and the core. If
there is continuity, replace the rotor.
.
STATOR CHECK
1. Check the continuity between the coil lead. If there is no
continuity, replace the stator.
2. Check the continuity between the coil and the core. If there
is continuity, replace the stator.
.
RECTIFIER CHECK
1. Check the continuity between the positive rectifier and the
stator coil lead connection terminal with a tester. If there is
continuity between the terminals, the diode is shorted, so
replace the rectifier.
