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Unlike other charging systems which have three wires
connected to the alternator, the CS-121 and CS-130 may be used with only two
wires connected to the alternator. The output wire to the battery positive,
and an "L" terminal wire connected to the charge indicator bulb,
or to the resistor, or to both. A basic wiring circuit is shown (Figure 3).
The charge indicator works in much the same way as on
other charging systems-the indicator lights when the switch is closed, and
then goes out when the engine is running. If the charge indicator is on with
the engine running a charging system defect is indicated. For all kinds of
defects, the indicator will glow at full brilliance. A new feature of this
regulator is that it will cause the charge indicator to be on with the
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engine running if the system voltage is too high or
too low. The regulator is temperature-compensated; that is, it's voltage
setting varies with temperature.
As in other alternators, the regulator limits the system
voltage by controlling the rotor field current. Unlike other
regulators, this regulator switches the field current on and off at a fixed
frequency of about 400 cycles per second. By varying the on-off time, the
correct average field current for proper system voltage control is obtained.
At high speeds, the on-time may be 10% and the off- time 90%. At low speeds
with high electrical loads the on-off time may be 90% and 10% respectively.
The use of the "P", "F", and
"S" terminals is optional. The "P" terminal is connected
to the stator, and may be connected externally to a tachometer or other
device. The "F" terminal is connected internally to field
positive, and may be used as |
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a fault indicator. The
"S" terminal may be connected externally to a voltage, such as
battery voltage, to sense the voltage to be controlled. For complete
circuit, reference must be made to the vehicle manufacturer's wiring
diagrams.
Where the regulator is identified with an "I"
marking on the regulator case, the circuit in Figure 3A applies. In this
circuit, both the "L" and "I" terminals serve to turn on
the regulator and allow field current to flow when the switch is closed. The
"I" terminal may be connected directly to the switch, or through a
resistor. Both are illustrated. The "I" circuit may be used with
or without the "L" circuit; that is, with or without
anything connected to the "L" circuit.
The vehicle circuit can be identified, Figure 3 or Figure
3A, by observing the terminal marking on the regulator, which will be either
an "F" (Figure 3) or "I" (Figure 3A).
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