Chevrolet 10 Series 1968, Service Manual, Page: 441 / 713

ENGINE-ELECTRICAL 6Y-16
V _________ ___/
VOLTMETER
DDU
WIRING HARNESS
F ig . 14c—V oltage Tests
winding will be slightly higher than the specified
value. This is true because the specified value
is for an ohmmeter reading directly across the
slip rings.
F ig . 15c—Field Resistance Tests
F ig . 16c—C ir c u it Resistance Test
6 . Disconnect ohmmeter and reconnect the battery
ground strap.
Testing Circuit Resistance
Excessive resistance in the sensing circuit, consisting
of all field leads and the regulator, can cause an over­
charged battery.
1. Turn on switch but do not start engine.
2. Alternately connect a voltmeter as shown in Part 1
and Part 2 in Figure 16c.
3. If the two voltmeter readings total more than .3
volt, check for excessive resistance in field circuit
leads. If these leads are satisfactory, the field relay
contacts may have excessive resistance. In this case
replace the relay.
V oltage Setting Adjustment
A voltage setting not tailored to meet vehicle require­
ments can result in an undercharged or an overcharged
battery. To adjust the voltage setting, proceed as follows:
1. Connect a voltmeter to the adapter as shown in
Figure 14c, Part 1.
2. Connect an ammeter in the circuit at the “ B AT”
terminal on the generator.
3. Turn all accessories off.
4. Operate generator at approximately 3000 rpm (1500-
2000 engine rpm).
5. The generator output should be at least 10 amperes
below the rated generator output for this check.
Example: If generator rated output is 130 amps, the
regulator is limiting voltage if amperage is
120
or less.
CHEVROLET TRUCK SERVICE MANUAL