Cadillac 60 Series 1963 Shop Manual page 284

ELECTRICAL SYSTEM 12-3
sink", which is insulated from the end frame. The
six diodes change the alternating current voltages
developed in the stator windings to direct current
voltage at the "BAT", or output, terminal of the
generator.
The regulator unit is mounted on the right side
of the radiator support in a waterproof case. A
double contact voltage regulator and a field relay
are the principal parts of this assembly. The
voltage regulator unit limits the voltage output.
The field relay unit connects the generator field
winding and regulator winding to the battery.
The regulator internal circuits are shown in the
wiring diagram, Fig. 12-1. When the ignition
switch is in the "On" position, the tell-tale gen-
erator lamp glows to indicate that the generator is
not charging. Current then flows from the positive
battery terminal, through the battery terminal on
the switch, through the indicator lamp and resistance
wire (which are in parallel), and on to the regu-
lator No. 4 terminal.
Within the regulator unit, current flows through
the lower set of voltage regulator contact to the
" F " terminal. Current then flows through the
generator field winding to ground. Enough current
is thus supplied to the field windings to insure
that the stator winding voltage is built up when
the engine starts.
As the generator begins to operate, voltage from
the "R" or relay terminal of the generator flows
to the regulator No. 2 terminal, causing the field
relay contacts to close. The regulator No. 4 ter-
minal is then connected directly to the battery
through the field relay contacts, which applies 12
Regulator
Resistance Wife
— \ w
20 Ohm
Battery
Stator Windings
T
Generator
•Field Windings
Fig. 12-1 Charging Circuit
volts to the ground side of the tell-tale indicator
lamp, causing the indicator lamp to go out. Gen-
erator field current flows from the battery to the
regulator No. 3 terminal and through the field relay
contacts and the voltage regulator lower contacts
to the field winding.
As the generator rpm increases, the voltage at
the "BAT" or output terminal also increases.
This impresses a higher voltage through the field
relay contacts and across the voltage regulator
shunt windings. The magnetism developed in the
windings causes the lower, or series, contacts
of the voltage regulator to separate. The field
current then flows to ground through a resistor
that reduces field current.
This reduced field current causes the generator
voltage output to decrease, thereby decreasing tke
magnetic pull of the voltage regulator shunt wind-
ing. A spring overcomes the weakened magnetism
and closes the contacts. This cycle repeats itself
many times per second to limit the generator volt-
age to the pre-set value.
As the generator speed increases even further,
the resistor connected across the contacts is not
large enough to maintain voltage control of the
contacts. However, when the voltage increases
slightly above the setting, this causes the upper
or "shorting" contacts to close. When this happens,
the generator field winding is shorted so that no
current passes through the winding.
With no current in the field winding, the generator
voltage output decreases sharply. This reduces the
magnetism in the shunt winding and allows the upper
contact points to open. With these points open, field
current again flows through the resistor and the
field winding. As the voltage increases, the con-
tacts again close. This cycle repeats many times
per second to limit the generator voltage to the
pre-set value at high generator speeds.
The voltage regulator unit operates to limit the
value of the generator voltage throughout the entire
generator speed range, protecting all electrical
units and accessories from too high a voltage,
which could damage them.
The headlight control switch, Fig. 12-2, is
located on the instrument panel at the left of the
instrument panel cluster. In addition to the head-
lights, it also controls parking lights and interior
lights.
The amber colored parking lights can be turned
on by pulling the control switch knob half-way out.
The headlights operate when the knob is pulled
all the way out. The instrument panel lights can
be turned on when the knob is in either position,
afid their intensity can be varied from bright to
off by rotating the knob to the right. The interior
lights may be turned on by rotating the headlight
control knob to the extreme left.