3412 INDUSTRIAL ENGINES Caterpillar

Alternators And Regulators

Usage:

9G9538 Alternator (24V 50A)

NOTE: Load the battery with a carbon pile (4C4911 Battery Load Tester) to get the maximum alternator output.

Polarity ... Negative Ground

Rotation ... Either Direction

Minimum full load current at 5000 rpm ... 45A

Minimum full load current at 1500 rpm ... 14.5A

Output voltage ... 27.5 ± 1.0V

(1) Shaft nut torque ... 102 ± 7 N·m (75 ± 5 lb ft)

(2) Regulator.

Voltage setting ... No adjustment

Permissible voltage range ... 26.5 to 28.5V

(3) Torque for positive terminal nut ... 14 ± 1 N·m (10 ± .7 lb ft)

(4) Torque for ground terminal nut ... 2.25 ± 0.25 N·m (20 ± 2 lb in)

3T1888 Alternator (24V 50A)

NOTE: Load the battery with a carbon pile (4C4911 Battery Load Tester) to get the maximum alternator output.

Polarity ... Negative Ground

Rotation ... Either Direction

Speed for testing (rpm) ... 5000

Output voltage ... 27.5 ± 1.0V

Output (cold) ... 54A

(1) Torque for the pulley nut ... 102 ± 7 N·m (76 ± 5 lb ft)

(2) Torque for the output terminal nut ... 13.5 ± 1.3 N·m (10 ± 1 lb ft)

7N0129 Regulator (Mounted inside regulator)

Voltage setting range ... 27.5 ± 1.0V

Adjust voltage setting to ... 28V

NOTE: There are two types of adjustment: One type of adjustment is made by removing a pipe plug and turning the adjusting screw one or two notches in a clockwise direction to increase the voltage setting. The second type of adjustment is similar except, remove the end cover to expose the potentiometer for adjustment.

Then increase speed to get a maximum output of ... 50A