Buick LeSabre 1965 Service Manual page 587

ELECTRICAL SYSTEMS
GENERATOR-CHARGING SYSTEM 1 0 - 1 7
BRUSH HOLDER
ASSEMBLY
LEAD ATTACHING NUTS
Figure 10-16—Internal Leads
maximum. The field relay con-
nects and disconnects the voltage
regulator and generator f i e l d
directly to the battery. The in-
dicator lamp lights at about 1/2
brightness when the i g n i t i o n
switch is turned on; when the
engine is started, the indicator
light goes out. If the indicator
light ever comes on with the
engine running, trouble in the
charging system is indicated.
10-17 OPERATION OF
CHARGING SYSTEM
Before the generator will put out
any current, the rotor field must
be energized. The rotor poles
have practically no residual mag-
netism, so u n l e s s current is
"F" TERMINAL
NO. 2 TERMINAL
NO. 3 TERMINAL
NO. 4 TERMINAL
VOLTAGE
REGULATOR
JUNCTION
BLOCK
BATTERY
RESISTANCE WIRE
SWITCH
INDICATOR
LAMP
DELCOTRON
REGULATOR
Figure 10-18—Del cotron Generator Wiring
Figure 10-17—Regulator
supplied to the field from the
battery, there can be no output
from the generator.
When the ignition switch is turned
on, current flows immediately
through the field to ground inside
the generator. Before the engine
is started, the path of the field
current is f r o m the junction
block, to the "BAT" terminal of
the ignition switch, through the
switch to both the "IGN" and
the "ACC" terminal. From the
"IGN" terminal, current flows
through the generator indicator
light in the instrument cluster
(causing it to light), to the " 4 "
terminal of the regulator. See
Figure 10-22.
The indicator light circuit allows
only about 1/4 ampere to flow,
which is not sufficient to initially
energize the field. Therefore, a
parallel circuit is necessary; this
circuit allows about 3/4 ampere
to flow from the "ACC" terminal,
through the large cowl connector,
through a 10 ohm resistance wire
to the " 4 " terminal of the regu-
lator. The combined current of
about one ampere flows through
the lower contacts of the voltage
closed by t h e
" F " terminal of
" terminal
regulator (held
spring), out the
the regulator, in the " F
of t h e generator, through the
brush and slip ring to ground. See
Figure 10-19.
When the engine is started, the
stator windings immediately put-
out a voltage. This voltage is
conducted from one phase of the
stator, out the "R" terminal of
the generator, in the " 2 " ter-
minal of the regulator, through
the field relay windings to ground.
Even a low voltage at the field
relay is sufficient to overcome
the spring tension of the arma-
ture, thereby closing the field
relay contacts.
The instant the field relay closes,
the field current is supplied di-
rectly from the battery instead
of through the ignition switch and
resistance wire. The field cur-
rent then comes from the battery,
into the " 3 " terminal of the re-
gulator through the field relay,
and on through the field as before.
This allows the same voltage to
be present at the " 4 " terminal
as at the ignition switch, there-
by causing c u r r e n t to stop