SECTION 3 - CHASSIS & SCISSOR ARMS
3121166 – JLG Lift – 3-33
NOTE: Reference Figure 3-29., Drive Motor Components for
part names and locations when servicing the Drive
Motor.
Periodic maintenance consisting of inspections of motors,
batteries and wiring circuitry is recommended.
ALWAYS WEAR EYE PROTECTION DURING ANY MAINTENANCE
OPERATION.
Drive Motor Troubleshooting
1. Turn off power to unit and disconnect main battery
power. Disconnect drive motor connections from the
Power Module.
2. Verify field continuity between the blue and orange
wires. If available, use a 4-wire ohmmeter to verify
the field resistance per the applicable motor specifi-
cation below.
3. Verify armature continuity between the red and black
wires. If available, use a 4-wire ohmmeter to verify
the field resistance per the applicable motor specifi-
cation below.
4. Using a dielectric tester, verify that there are no
shorts between the following items:
a. Field connector pins and the case of the motor.
b. Armature terminals and the case of the motor.
c. Field connector pins to the armature terminals.
5. Verify continuity in 2 pin brake connector (yellow
and brown wires). Measure the brake resistance and
verify that it is between 18 and 22 Ohms.
Drive Motor Disassembly
NOTE: Refer to Figure 3-29.
1. Remove the two Cover Plate Mounting Screws (14)
holding the Cover Plate (13) in place and remove the
cover plate from the motor.
2. Remove the Brake Cover Mounting Screws (15)
holding the Brake (11) in place and set aside. These
screws are used to manually release the brakes.
3. Remove the two Terminal Cover Mounting Screws
(16). Slide the strain relief of the Wire Harness (1)
out of the cover and remove the cover from the
motor.
4. Discard the Gasket (12) that was located under the
brake and terminal covers.
5. Remove the wire harness from the motor by discon-
necting the brake connection and armature connec-
tions. Cut the field connection close to the crimp
connection on the motor side.
6. Install the two Brake Cover Mounting Screws (15)
into the threaded holes in the brake assembly and
tighten to manually release the brake (see Figure 3-
10.).
7. Remove the three screws holding the brake assem-
bly to the motor. Carefully remove the brake assem-
bly, brake disc and reaction disc from the motor by
sliding off of the shaft.
8. Remove the screws holding the Commutator End
Head (9) in place and remove the commutator end
head from the frame and field assembly. The Arma-
ture (2) will be attached to the commutator end
head.
9. Pull back the Brush Springs (4) in the commutator
end head, pull the brush back and rest the springs
on the side of the brush. The brushes should move
freely within the holders.
10. Use an arbor press or a bearing puller to remove the
armature from the commutator end head assembly.
11. Remove the Snap Ring (7) and Bearing (8) from the
commutator end head. Discard the bearing.
Drive Motor Inspection and Service
NOTE: Refer to Figure 3-29.
1. Carefully blow out any accumulated carbon dust
and dirt from the Commutator End Head (9) and the
Frame & Field Assembly (2) using clean, oil free,
compressed air.
2. Replace Brushes (5) that are worn below their
usable length of 0.6 in (1.5 cm), show signs of
uneven wear or signs of overheating, such as discol-
ored brush shunts and brush springs. Brushes
should always be replaced in complete sets of four.
Use identical replacement parts; do not substitute
brush grades as the brushes are matched to the
motor type and application to provide the best ser-
vice. Substituting brushes of the wrong grade can
cause premature commutator failure and excessive
brush wear.
3. Make sure the Brush Box Assembly (6) is tight on
the commutator end head. Replace brush box
assemblies in the commutator end head if they are
Model
Field Resistance
@ 75°F (24°C)
Armature Resistance
@ 75°F (24°C)
1930ES 0.21 Ohms 0.037 Ohms
2030ES/2630ES/
2646ES/3246ES
0.127 Ohms 0.051 Ohms
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