Do not allow voltage to exceed the recommended voltage setting of the regulator .
(5) Adjust the load rheostat to obtain 28 volts. When the correct voltage is obtained, the ammeter should read
(6) If the correct output is not obtained. replace the alternator.
(7) If the correct output is obtained and the batteries are not charging correctly, check remainder of the
(8) Remove test set harness, reconnect all electrical leads, then remove tags.
(9) Install battery cables.
c. Removal and Installation.
(1) Remove battery cables and tie back to prevent flash currents.
(2) Tag correctly for position, then remove all electrical leads from alternator.
(3) Remove alternator in manner similar to that described for generator (para 3-83).
d. Cleaning, Inspection and Repair'.
(1) Clean exterior of alternator with a rag dampened in an approved cleaning solvent then dry thoroughly.
Blow all dust from brush area with low pressure compressed air.
(2) Visually inspect all mounting hardware for wear or stripped threads. Inspect alternator for cracks or breaks
in pulley, housing, or end bells. Inspect belt for wear, frayed condition, or deterioration.
(3) Repair by replacing defective hardware, belt, or alternator.
e. Belt Removal, Installation and Adjustment.
(1) Removal and installation. Remove alternator belt in manner similar to that described for generator (para 3-
in reverse order.
(2) Adjustment. Adjust generator belt as shown on figure 3-22.
3-85. Generator Regulator (For Engine Model 687C-18-ES).
a. On Equipment Test.
(1) Remove electrical leads from voltage regulator (fig. 3-71).
(2) Test voltage regulator in conjunction with generator (para 3-83) by using connections illustrated in view B.
figure 3-74. Polarize generator
by momentarily touching jumper wire
(3) Start generator and gradually increase speed until cutout relay point close. Closing voltage should be 26
(4) With generator operating at 4,000 RPM, reading on voltmeter should be 28.2 volts, and ammeter should
read 40 amperes.
(5) If requirements of (3) and (4) above are not met, regulator is defective, and must be replaced.