Chevrolet 10 Series 1967, Service Manual

Page: 357 / 605

ENGINE-ELECTRICAL 6Y-9
The voltage at which the generator operates is deter­
mined by the regulator adjustment. The regulator voltage
setting can be adjusted externally by removing a pipe
plug in the cover (fig. 3c) and turning the adjusting arm
inside the regulator. This procedure is explained in the
following section, and permits regulator adjustments
without removing the cover.
The full transistor regulator used with the 130 amp
generator (fig. 4c) is a completely static unit composed
principally of transistors, diodes, capacitors and re ­
sistors. The rotor field current is controlled by differ­
ences in internal voltage and resistance values acting on
the transistors, diodes and resistors within the regulator.
This unit has certain differences from the other
assemblies.
1. The regulator units are not grounded in the regula­
tor. They are connected to a third lead which is
brought out of the regulator to a ground location.
2. It does not use a thermistor for automatic tempera­
ture compensation, because the quantity of current
handled by the system does not warrant the minute
corrections this unit is designed to make.
3. The regulator itself is not grounded.
4. It is used with an ammeter and a field relay in the
system.
Wiring harnesses are protected by fusible links. A
fusible link is a length of special wire, normally four
gauges sm aller than the circuit it is protecting, used
in circuits that are not normally fused such as the
ignition circuit. The same size wire with a hypalon
insulation must be used when replacing a fusible link.
The links are located in the engine compartment
wiring harnesses and each link will be identified with
its gauge size. On most models there is a 16 gauge,
red wire fusible link installed as an integral part of
the positive battery cable or located between the solenoid
battery terminal and the junction block. On tilt cab
models (TE 40-50-60, TT 40, TD-TG 50-60) this link
is a 14 gauge, red wire. School bus models have an
additional link (16 gauge, red wire) located in the battery
feed circuitry between the engine generator and forward
lamp harness connector and molded splice junction.
FIELD RELAY
REGULATOR
BATTERY
GENERATOR
PLUG
(REMOVE TO ADJUST
VOLTAGE SETTING)
"POS."
"NEG."
Fig. 4 c —V o lta g e Regulator for 130 Amp System
MAINTENANCE AND ADJUSTMENT
At regular intervals, inspect the terminals for cor­
rosion and loose connections, and the wiring for frayed
insulation. Check mounting bolts for tightness. Check
the drive belt for alignment, proper tension and wear.
Because of the higher inertia and load capacity of the
rotor used in A.C. generators, PROPER BELT TEN­
SION is more critical than on D. C. generators.
Since the Delcotron and its companion regulator are
designed for use on negative polarity systems only, the
following precautions must be observed.
Failure to
observe these precautions may result in serious damage
to the charging system.
1. When installing a battery, always make absolutely
sure the ground polarity of the battery, generator
and regulator is the same.
2. When connecting a booster battery, make certain
to connect the correct battery terminals together.
3. When connecting a charger to the battery, connect
the correct charger leads to the battery terminals.
4. Never operate the generator on an uncontrolled open
circuit. Make absolutely certain all connections in
the circuit are secure.
5. Do not short across or ground any of the terminals
on the generator or regulator.
6
. Do not attempt to polarize the generator.
7. Do not disconnect lead at generator without first
disconnecting battery ground cable.
Trouble in the A.C. charging system will usually be
indicated by one or more of the following conditions:
1. Faulty indicator lamp or ammeter operation.
2. An undercharged battery (usually evidenced by
slow cranking speeds).
3. An overcharged battery (usually evidenced by ex­
cessive battery water usage).
CHEVROLET TRUCK SERVICE M ANUAL