SCREW 3K4724 - Caterpillar

Note: The proper drive pulley is required for the correct alternator output.
Table 2
Tools Needed    
Qty     Part Number     Description    
1     6V-7070     Digital Multimeter    
1     8T-0900     Ammeter Tool Gp    Machine Test
Put the multimeter positive (+) lead on the B+ terminal of the alternator. Put the negative (-) lead on the negative (-) terminal or frame of the alternator. Put the 8T-0900 Ammeter Tool Gp around the positive output wire of the alternator.
Turn OFF all electrical accessories. With the fuel OFF, crank the engine for 30 seconds. Wait 2 minutes to let the starting motor cool. If the system appears to operate at the specifications, crank the engine again for 30 seconds.Note: Cranking the engine for 30 seconds partially discharges the batteries in order to do a charging test. If batteries are already low in charge, skip the Step 2. Jump-start engine or charge batteries as required.
Start the engine and run at full throttle.Note: Full throttle approximates the required drive pulley speed of 5000 rpm.
Immediately check output current. When operating correctly, this initial charging current is equal to or greater than the full output current specification shown below: 8C-5535 Charging Alternator Gp ... 29A 7T-2876 Charging Alternator Gp ... 55A 9W-3043 Charging Alternator Gp ... 52A 2Y-4212 Charging Alternator Gp ... 17A 2Y-8310 Charging Alternator Gp ... 21A 3E-7295 Charging Alternator Gp ... 55A 9X-0341 Charging Alternator Gp ... 90A
The alternator output should stabilize within approximately 10 minutes at full throttle (possibly longer, depending upon battery size, condition and alternator rating). When operating correctly, the alternator output voltage is:12V System ... 14.0 0.5V24V System ... 27.5 1.0VIf the alternator is NOT performing within specifications, refer to Table 1.
The charging current during this period should taper OFF to less than approximately 10A, depending again upon battery and alternator capacities. If the charging current does NOT decrease as specified, refer to Table 1.
Illustration 1 g03227737
Charging circuit of 7T-2876 Charging Alternator Gp (1) Start switch (2) Fuel shutoff solenoid (3) 7T-1183 Resistor (4) Fuse block (5) Main relay (6) Tachometer (7) 7T-2876 Charging Alternator Gp (8) Battery (9) Diode Wire As
The K1/N1 alternators are self-excited at high speeds. For this reason, they are turned on by the battery, through the ignition or key start switch, to start the charging process at low speed. They are turned ON at any time the ignition or key start switch is either in the ON or START position. The charging circuit shown above is for the 7T-2876 Charging Alternator Gp. If there is low or no alternator output, check the circuit between the key start switch and the alternator for an open. Also check the resistor and diode (if equipped). The resistance of the resistors should be as follows: 7T-1183 Resistor for 7T-2876 Charging Alternator Gp ... 22 4ohms 6T-7864 Resistor for 9W-3043 Charging Alternator Gp ... 39 2ohms
On lift trucks, check the alternator light to make sure