JLG Skytrak 6036 Service Manual page 219

c. Alternator Removal
1. Disconnect negative (–) cable (2, Fig. 10.38)
from batteries.
2. Remove screw (1, Fig. 10.28), lock washer
(2), and washer (3) from tapped hole in
alternator.
3. Remove screw (4), lock washer (5), lever (6),
and spacer (7) from tapped hole in engine.
4. While supporting the weight of the alternator
(22), remove self-locking nut (8), washer (9),
screw (10), sleeve (11), and sleeve (12); lift
the alternator from the forklift and carry it to a
clean work bench.
5. If necessary, remove hex nuts (13), washers
(14), washers (15), bracket (16), and stud
(17).
6. If necessary, remove hex nut (18), washer
(19), belt (20), and pulley (21).
d. Alternator Disassembly
1. Remove the four thru-bolts and pry alternator
apart with a screwdriver at the stator slot.
2. After disassembly, place a piece of tape over
the slip ring end frame bearing to prevent
entry of dirt and other foreign material, and
also place a piece of tape over the shaft on
the slip ring end.
3. If brushes are to be reused, clean with a soft
dry cloth.
4. To remove the drive end frame from the rotor,
place the rotor in a vise and tighten only
enough to permit removal of the shaft nut (18,
Fig. 10.28).
USE OHMMETER TO CHECK
FOR SHORTS AND OPENS
Fig. 10.29 Checking Rotor Winding
Model 6036 S/N 9B0499 and Before
e. Rotor Field Winding Checks
1. To check for opens, connect the test lamp or
ohmmeter to each slip ring (refer to Fig.
10.29). If the lamp fails to light, or if the
ohmmeter reading is high (infinite), the wind-
ing is open.
2. Connect test lamp or ohmmeter from one slip
ring to shaft. If lamp lights, or if reading is low,
the rotor winding is grounded (not illustrated).
CAPACITOR
DIODE
TRIO
RECTIFIER
BRIDGE
ATTACHING
Fig. 10.30 Inside View of 10-SI End Frame Assembly
3. Check the winding for short-circuits or exces-
sive resistance by connecting a battery and
ammeter in series with the edges of the two
slip rings. The field current ammeter reading
at 80 °F (26.7 °C) should be 4.2 to 5.0 A. A
reading above this range indicates shorted
windings; a reading below this range indicates
excessive resistance. An alternate method is
to check the resistance of the field by connect-
ing an ohmmeter to the two slip rings. If the
resistance reading is below 2.4 to 2.8 ohms,
the winding is shorted; if above this range, the
winding has excessive resistance. The
specified resistance value can be determined
by dividing the voltage by 4.2 and 5.0 A.
4. Remember that the winding resistance and
ammeter readings will vary slightly with
winding temperature changes. If the rotor is
not defective, but the alternator fails to supply
MA1121
rated output, the defect is in the diode trio, Fig.
10.30, rectifier bridge, stator, or regulator.
Section 10. Electrical System
INSULATING
WASHERS
RESISTOR (USED ON
SOME MODELS)
NUTS
(12 SI Is Similar)
MA1131
10-25