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Hummer H1 (2002+). Manual - part 199

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Electrical System 12-23

05745159

ALTERNATOR OVERHAUL

Alternator Disassembly

Remove alternator.

Mark drive end frame and slip ring end frame for
assembly alignment reference.

Hold rotor shaft with allen wrench and remove nut,
washer, pulley, fan, and thin collar from rotor shaft
(Figure 12-38).

Remove four through-bolts from slip ring end frame and
drive end frame.

Remove drive end frame and thick collar from rotor shaft.

Remove three nuts from stator leads and rectifier bridge.

Remove stator from slip ring end frame.

Remove standard screws, insulated screws, and washer
from components in slip ring end frame.

Remove nut and output stud with insulator from slip ring
end frame.

10. Remove rectifier bridge, capacitor strap, regulator

connector strap, and brush holder from slip ring end
frame.

11. Unsolder and separate brush holder and regulator

connector.

12. Unsolder and separate connector strap from regulator.

Figure 12-38: Alternator Components

OUTPUT

STUD

INSULATOR

SLIP RING

END FRAME

REGULATOR

STUD

BRUSH

HOLDER

BRUSHES

INSULATED

SCREWS

CAPACITOR

STRAP

REGULATOR

CONNECTOR STRAP

RECTIFIER

BRIDGE

BEARING

SLIP RING

ROTOR

SHAFT

THICK

COLLAR

STATOR

LEAD

STATOR

DRIVE END

FRAME

THIN

COLLAR

FAN

PULLEY

4-1-00

12-24

Electrical System

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Alternator Parts

Cleaning

Use part cleaning solvents on metal parts only. The insulating
coatings on wires in the field coil and stator can be damaged by
cleaning solvents.

Clean encapsulated and exposed wire items by wiping with a
clean cloth.

Inspection and Repair

Rotor

Inspect for cracked slip rings, damaged threads, and galling or
scoring on bearing journal surfaces on shaft (Figure 12-39).

Corrosion or light scoring on the slip rings may be removed
with 400 grit emery cloth.

Test the slip rings and field coil for opens (high resistance),
shorts (very low resistance), and grounds (low resistance) to
frame and shaft. Replace the rotor if a fault is detected.

Inspect the ball bearing for free play, roughness, leaking seals,
and other damage. Replace the bearing if necessary. Seat the
new ball bearing against the rotor shoulder.

Figure 12-39: Rotor Inspection Points

Stator

Check the stator leads for continuity to ground (laminations).
Any continuity indicates a grounded stator which should be re-
placed (Figure 12-40).

Examine the stator winding for discoloration due to overheat-
ing or short to ground. Normal color is reddish brown to pur-
ple. Bare copper, dark spots, or dull black color indicates
burned spots.

Replace the stator if damaged, shorted or grounded.

Figure 12-40: Stator Inspection Points

Rectifier Bridge

Test the rectifier bridge as follows:

The bridge studs are embedded in insulation. To obtain
diode readings, the ohmmeter leads must contact the cop-
per strap.

Connect the ohmmeter leads to the grounded side and
strap as shown and take readings at each strap
(Figure 12-41).

Repeat step 1 with test leads reversed.

All three readings in steps 1 or 2 should read high
resistance in one case and low resistance in other case.

Connect ohmmeter leads on positive side and strap as
shown, and take readings at each strap (Figure 12-41).

Repeat process of step 4 with leads reversed.

All three readings in steps 4 and 5 should be the same,
with resistance high in one set and low in the other set.

If any one reading in steps 1, 2, 3, and 4 is not the same as
the other two readings, replace rectifier bridge.

BALL

BEARING

SHOULDER

SLIP RINGS

WINDINGS

SHAFT

THREADS

STATOR

LAMINATIONS

STATOR LEADS

WINDINGS

4-1-00

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Electrical System 12-25

05745159

Figure 12-41: Rectifier Bridge Check

Regulator

Figure 12-42: Regulator Inspection Points

Inspect the regulator for cracks, breaks, broken contacts, or
surface defects and replace if damaged (Figure 12-42).

Brushes and Brush Holders

Figure 12-43: Brush Holder and Brushes

Check for broken or disconnected brushes, worn brushes with
length less than 0.5 in. (12.7 mm), and broken or distorted
springs. Replace brush holder and brushes as an assembly if
necessary (Figure 12-43).

NOTE: The pin that retains the brushes temporarily can be
made from locally obtained parts. A standard paper clip can be
used.

Assemble springs and brushes in the brush holder. Compress
the springs and brushes in the holder and hold them in position
with the temporary pin (pin will be removed after assembly)
(Figure 12-43).

Drive End Frame and Bearing

Inspect the bearing for roughness, looseness in bore, inner race
free play, or damaged seals. Replace the end frame and bearing
as an assembly if damaged (Figure 12-44).

Figure 12-44: Drive End Frame Inspection

Inspect the drive end frame for cracks, breaks, or damaged
threads. Replace the assembly if casting is cracked or broken.

Repair minor through-bolt and adjusting bolt thread damage
using a tap. For more serious through-bolt thread damage, re-
place the end frame.

OHMMETER LEADS

GROUNDED SIDE

STUDS

STRAP

POSITIVE SIDE

STRAP

OHMMETER LEADS

REGULATOR

CONTACTS

SPRING

BRUSH HOLDER

BRUSH

PIN

TEMPORARY

BEARING

DRIVE END

FRAME

4-1-00

12-26

Electrical System

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Fan

Inspect the fan for distortion, cracked blades, or broken blades.
Minor bending repair is permissible. For broken or missing
blade ends, cracks or breaks, replace the fan (Figure 12-45).

Figure 12-45: Fan Inspection Points

Slip Ring End Frame and Bearing

Inspect the bearing for roughness, looseness in retainer ring,
free play, loose inner race, or damaged seals. Replace the bear-
ing if damaged or loose (Figure 12-46).

Figure 12-46: Slip Ring End Frame

Inspect the slip ring end frame for breaks, cracks, evidence of
spun ball bearing, or damaged threads. Repair minor thread
damage. Replace the end frame if otherwise damaged.

Collars

Inspect both collars for cracks, bends, or scoring. Replace ei-
ther part if damaged (Figure 12-47).

Figure 12-47: Fan Spacers

Output Stud Assembly

Inspect the output stud assembly for cracked, or broken insula-
tor, distortion, or damaged threads. Replace the stud assembly
if any part is damaged (Figure 12-48).

Figure 12-48: Output Stud Inspection

Pulley

Inspect the pulley for distortion, breaks, or sharp edges in the
belt grooves. Remove minor burrs and sharp edges with fine
tooth file. Replace the pulley if damaged (Figure 12-49).

Figure 12-49: Alternator Pulley

Capacitor Strap

Inspect the capacitor strap for breaks, cracks, distorted case, or
surface defects. Check capacitor for continuity. Replace if
damaged (Figure 12-50).

Figure 12-50: Capacitor Strap

FAN

FAN BLADE

SLIP RING

END FRAME

BEARING

THIN COLLAR

THICK COLLAR

STUD

INSULATOR

NUT

OUTPUT STUD

ASSEMBLY

PULLEY

BELT GROOVES

STRAP

CAPACITOR

4-1-00

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