DETROIT DIESEL 53
7.1.1 Battery-Charging Generator Regulator
Fig. 5 - Transistor Regulator with Plug-ln Connecttons
changed, or rectified, to a D.C voltage which appears
The voltage regulator illustrated in Fig. 4 is designed
at the output. or "BAT". terminal on the generator.
for negative ground battery-charging circuits only. lt
The generator then supplies currept to charge the
has Iwo exposed terminals. The voltage setting may be
battery and operate vehicle accessories.
adjusted by relocating a screw in the base of the
regulator.
As generator speed Increases. the voltage reaches the
pre-set value and the components in the regulator
The voltage regulator shown in Fig. 5 has shielded
cause transistor TR-1 to alternately "turn off and
pluq-in connections and requires a cable and plug
"turn on" the generator held voltage The regulator
assembly to connect the regulator into the battery-
thus operates to Iimit the generator output voltage to
charging circuit. This type of regulator may be used in
the pre-set value.
negative ground, positive ground and insulated
charging circuits. The voltage setting may be adjusted
In the positive ground circuit, when the switch is closed
by removing a plug in the cover and turning a slotted
and the engine is not running, the field current can be
adjusting button inside the regulator.
traced from the battery positive ground to generator
ground. and then to the regulator "POS" terminal. The
current continues through diode D-1 and transistor
Operation
TR-1 to the regulator "FLD" terminal, and then
through the field winding and held relay contacts back
When the engine starting switch is closed, the field
to the battery, thus completing the circuit Except for
relay winding is energized, which causes the relay
this primary difference, this circuit operates in the
contacts to close.
same manner as that described for the negative
ground circuit.
In the negative ground circuit with the field relay
contacts closed and the engine not running, generator
field current can be traced from the battery through
the relay contacts to the regulator "POS" terminal.
REGULATOR PRECAUTIONS
Current then continues through the back-bias diode
Never short or ground the regulator terminals; do not
(D-l) and power transistor (TR-1) to the regulator
"FLD" terminal, and then through the generator field
attempt to polarize the circuit.
winding to ground, completing the circuit back to the
Make sure all connections in the charging circuit are
battery.
tight to minimize resistance.
When the generator begins to operate. A.C. voltages
Refer to "A.C Generator Precautions" in Section 7.1.
are induced in the stator windings. These voltages are
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