Single Phase, Half-Wave Rectifier; Diode Rectification Method; Internal Voltage Regulation Method - Honda Motorcycle Service Manual

BATTERIESICHARGINGILIGHTING SYSTEM
Single Phase, Half-Wave Rectifiers
(Diode rectification method)
This method uses only a diode to convert alternating current
to direct current. The diode allows current to flow in one
direction only. When a single phase AC waveform flows
through the diode, the negative voltage of the waveform is
cut off and the positive voltage drops slightly. As a result, the
output consists of the positive half-cycles of the input
Single phase half wave rectification is used in models with
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small electrical loads.
waveform. The signal is said t o have been rectified beca"se
only half cycles are utilized. This is called half-wave
rectification.
The single phase half wave rectifier utilizes t w o voltage feed-
back methods.
O
DC WAVEFORM
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g
REcT"
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(Internal voltage regulation method)
The circuit illustrated at right is the most basic regulator
circuit.
The signal from the charging coil is half-wave rectified through
diode D l , which is inside the regulatorirectifier circuit, and is
then fed to the battery.
Voltage is regulated by the voltage regulation circuit and the
SCR (thyristor1
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LIGHTINGICHARGING
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As the engine rpm (revolutions per minute) increases, the
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alternator output increases and is rectified by diode D2. This
signal then goes to the zener diode (ZD).
Current flows in the normal direction of the zener diode but
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does not flow i n the reverse direction until a certain amount
of voltage is applied in the reverse direction. When this
VOLTAGE CUT OFF REGULATED VOLTAGE
voltalne is reached, the zener diode a b r u ~ t l v conducts current in
/
the recerse direction. In this way, current /s fed to the gate of SCR
which then turns ON.
When the SCR turns ON, the output from the alternator is
shorted to ground through the SCR. This explains why the
battery becomes e r & if the ground wires o f the
regulatorirectifier are broken or poorly connected.
For alternators w i t h a combined chargingilighting coil
(charging and lighting systems powerd by the same coil), the
headlight lighting system aftects battery charging. Since the
input of the lighting system is taken from the charging coil, if
the lighting coil load is unsuitable battery charging will be
unstable.To prevent this from happening,when the headlight
is off, the output from the charging coil is connected t o a
resistor equivalent to the impedance of the headlight.
Keep i n mind that if the lighting output lines are broken or
shorted, or it the switch has contact problems, the charging
system is adversely affected.
Date of Issue : March, 1995
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HONDA MOTOR CO.,LTD.