Voltage Regulator Adjustment.

c. Installation. Refer to figure 3-27 and install the

voltage regulator as follows:

(1) Install regulator on battery box and secure

with three screws, nuts, and lock washers.

(2) Connect three wires to proper terminals on

regulator.

d. Voltage Regulator Adjustment. Slight adjust-

ments can be made at the voltage regulator to in-

crease or decrease battery charging rate.

(1) If battery is overcharging (indicated by bat-

tery using too much water) at normal setting, adjust

regulator as follows:

(2) Remove access plug (fig. 3-28) and note posi-

tion of slot in adjusting screw. The notches on the

case indicate adjustment areas. Center notch is mid-

point or normal setting. Each notch on sides of center

notch indicates a change of 0.3 volts.

(3) To decrease voltage, turn adjusting screw

counterclockwise one notch. This will decrease volt-

age 0.3 volts. Install access plug and check batters

condition during a reasonable period of operation. If

loss of water continues, repeat adjustment to further

decrease charging rate until normal operation occurs.

(4) To increase charging rate and keep batteries

charged as required, rotate adjusting screw (fig. 3-28)

counterclockwise as described above until normal

Figure 3-28. Voltage regulator adjustment.

operation is attained.

e. Testing Voltage Regulator. Test voltage regu-

lator to check voltage regulator setting as follows:

(a) 14.1 to 14.9 volts at 65F.

(1) Connect a voltmeter as shown in figure 3-29,

(b) 13.9 to 14.7 volts at 86F.

with one lead connected to regulator mounting screw

(c) 13.7 to 14.5 volts at 105F.

and other lead to No. 3 terminal on regulator.

(d) 13.5 to 14.3 volts at 125F.

(2) Operate engine at approximately 1500 rpm

(e) 13.4 to 14.2 volts at 145F.

for 15 minutes with truck lights on. Place a thermo-

(4) If voltage is not within the range for the

meter on the regulator and record temperature.

specified temperature, remove plug and adjust regu-

(3) The following readings, with regulator adjust-

lator as described in c above.

ment at midpoint, should be obtained on voltmeter

(5) If correct readings cannot be obtained, replace

for the temperature specified.

the regulator.

3-29