REVERSE
CURRENT
VOLTAGE
CURRENT RELAY
REGULATOR
REGULATOR
BATTERY
SERIES WINDING
SHUNT
WINDING
F
A
SHUNT
WINDING
SERIES
WINDING
R2
R1
GENERATOR
FIELD
BAT.
GEN.
ASf06033
Figure 6-33.--Dc charging circuit with a vibrating-contact regulator.
turns of fine wire and is shunted across the generator.
Dc Reverse Current Relay
The shunt winding consists of a few turns of heavy
The reverse current relay prevents the battery from
wire.
discharging through the generator when the engine is
The windings and core of the voltage regulator are
stopped or is running at slow speed. When the speed of
assembled in a frame, and a flat, steel armature with a
the generator is increased and the output voltage of the
contact point is attached to the frame by a hinge. A coil
generator becomes higher than that of the battery, the
spring (not shown) is attached between the armature
reverse current relay closes, completing the circuit from
and regulator base to hold the contact points in the
the generator to the battery. The generator powers the
closed position when the voltage regulator is not
entire electrical system and charges the battery.
working.
When the speed of the generator is decreased and
Current Regulator
the output voltage of the generator becomes lower than
the voltage of the battery, the reverse current relay
The current regulator protects the generator and
opens, which opens the circuit between the generator
charging circuit from overload by limiting current
and the battery. At this point the generator is
output to a preset value. The current regulator has a
inoperative and the battery powers the entire electrical
single winding of a few turns of heavy wire in series
system.
with the generator output. The entire output of the
The reverse current relay has two windings on a
generator passes through this winding. Except for the
single core. One consists of a few turns of heavy wire in
single winding, the construction of the current regulator
series with the charging circuit; the other consists of
is the same as the voltage regulator.
many turns of fine wire and is shunted across the
generator.
Resistors
The windings and core of the reverse current relay
Current and voltage regulators use two common
are assembled in a frame. A flat, steel armature with a
resistors mounted on the back of the regulator base;
contact point is attached to the frame by a hinge. A flat
they are referred to here as R1 and R2 (fig. 6-33). R1 is
spring holds the contact points open when the battery
connected between the regulator field terminal and
voltage is higher than the output of the generator.
ground at the regulator base. R2 is connected between
the regulator field terminal and the reverse current relay
Voltage Regulator
frame.
The voltage regulator prevents circuit voltage from
R1 is connected in series with the generator field
exceeding a preset value and maintains a constant
coils when either the voltage or the current regulator
voltage in the system. It has a series winding of many
contacts open. R2 is connected in parallel with the
6-27
