SR 4 GENERATOR
SYSTEMS OPERATION
VOLTAGE BUILD-UP CIRCUIT
To send the gate signal to controlled rectifier (CR9)
to let voltage increase from residual magnetism, a circuit
goes:
Front spade terminal (19) of rectifier module (A2),
through wire (19) to spade terminal (9) of regulator
module (A1).
Through regulator module (A1) to spade terminal
(10).
From spade terminal (10) of regulator module (A1)
through wire (10) to spade terminal (10) of rectifier
module (A2).
From spade terminal (10) on rectifier module (A2) to
the gate terminal on controlled rectifier (CR9).
NOTE: The voltage build-up circuit in regulator
module (A1) has a normally closed relay, a diode
rectifier and a current limiting impedance in it.
When generator voltage at the relay coil is at pickup
value (60 to 70% of rated voltage), the coil causes the
relay contact to open. Another circuit in regulator
module (A1) sends the gate signal to controlled rectifier
(CR9) one time each cycle. When engine speed is
lowered, voltage at the relay coil is lower. When the
voltage is less than the drop-out voltage, the relay
contact closes. Pickup voltage is generated at an
engine rpm less than the factory setting of low idle rpm.
The relay contact will open and close rapidly at an
engine speed of approximately 800 to 900 rpm. If it is
necessary to operate the engine at a speed less than the
factory setting of low idle, either fuse (F1) must be
removed or a single pole, single-throw toggle switch
must be installed between fuse (F1) and terminal (24) in
place of wire (24). The switch rating must be 250 volts,
15 amperes. When the fuse (F1) is removed or the
switch is open, the voltage can not go up and no
damage can come to the regulator.
Regulator module (A1) is sealed in an insulation of
epoxy. Inside the epoxy module (A1) are resistors,
capacitors, rectifiers, zener diodes, transistors and
amplifiers in circuits that are fastened to terminals (1 thru
11). This component is only available as a complete
unit:
GENERATOR REGULATOR ASSEMBLY
A1
Regulator module
CR9
Controlled rectifier
F1
Fuse
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