Chapter 5. ELECTRICAL AND COOLING SYSTEMS REPAIR INSTRUCTIONS

TM 10-3930-621-34

CHAPTER 5

ELECTRICAL AND COOLING SYSTEMS REPAIR INSTRUCTIONS

Section I. ALTERNATOR

(27) and rotor assembly (13) from the stator assembly

5-1. Description

(11) at the stator slot.

The alternator consists of two end frames, a stator and a

rotor. The rotor is mounted on a roller bearing at the

Note. Separation is made between stator assembly

retainer end. Two brushes carry current through two

frame (11) and drive end frame (27), not between stalor

rotor slip rings to a field coil mounted on the rotor. The

assembly and slip ring frame (2).

stator windings are assembled inside a laminated core

e. Separate stator assembly frame (11) from slip

and are connected to six semiconductor device diodes,

ring frame (2). The fit between these frames is not tight

which are mounted in the slip ring end frame. The

and separation may be accomplished without prying.

diodes function in changing the stator-rotor AC voltage to

f. Remove bearing (24) and retainer (1) from slip

battery usable DC voltage. A capacitor is also mounted

ring frame (2).

on the slip ring end frame and serves to protect the

g. Place a piece of tape over bearing (24) and over

diodes from high voltage input.

slip ring end of rotor shaft (13) to prevent entry of dirt and

other foreign material.

5-2. Removal

Caution: Use pressure sensitive tape. Friction

Refer to TM 10-3930-621-12 for alternator removal

tape will leave a gummy deposit on shaft, resulting in

procedures.

bearing drag and wear.

h. Place rotor assembly (13) in vise and tighten only

5-3. Disassembly

enough to hold assembly secure.

a. Refer to figure 5-1 and disassemble as follows:

Caution: Do not tighten excessively as this could

b. Remove four thru-bolts (23) from alternator

distort the rotor.

assembly.

i. Remove rotor shaft nut, lock washer, fan pulley,

c. Scribe a mark on the stator (11) and drive (27)

and spacer and separate drive end frame (27) from rotor

and slip ring (2) frames to aid in positioning parts during

shaft 113).

assembly.

d. Using a screwdriver, pry the drive end frame

KEY to, fig. 5-1:

1. Bearing retainer

16.

Semiconductor device, diode

2. Slip ring frame

17.

Terminal

3. Capacitor

18.

Terminal package, ground

4. Retaining spring

19.

Screw

5. Heat sink

20.

Flat washer

6. Terminal package, battery

21.

Nonmetallic washer

7. Brush holder with brushes

22.

Semiconductor device, diode

8. Spring

23.

Thru bolt

9. Insulator

24.

Bearing

10. Screw

25.

Bearing retainer

11. Stator assembly

26.

Gasket

12. Terminal lug

27.

Drive frame

13. Rotor assembly

28.

Bearing

14. Nut

29.

Collar

15. Lock washer

30.

Screw

5-1