JLG 1230ES Service Manual - Manual (Page 52)

SECTION 4 - BASE COMPONENTS
4-16 – JLG Lift – 3121222
Drive Motor Inspection and Servicing
(Reference Figure 4-5. - Drive Motor Disassembly Illustra-
tion)
1. Carefully blow out any accumulated carbon dust
and dirt from the end head and the frame and field
assembly using clean, oil free, compressed air.
2. Replace brushes (3) that are worn below their
usable length (.600 in.), show signs of uneven wear
or signs of overheating, such as discolored brush
shunts and brush springs. Brushes should always
be replaced in complete sets of four or eight. Use
identical replacement parts; do not substitute brush
grades as the brushes are matched to the motor
type and application to provide the best service.
Substituting brushes of the wrong grade can cause
premature commutator failure and excessive brush
wear.
3. Make sure the brush box assembly (5) is tight on the
commutator end head. Replace brush box assem-
blies in the commutator end head if they are physi-
cally damaged or brush holders are loose on the
brush plate.
4. Visually inspect the frame and field assembly (1) for
overheating or other signs of damage. Check all wir-
ing to insure that the insulation is in good condition.
Verify that pole screws are torqued to 250-300 in-lb
[28.2-33.9 N-m]. Verify field resistance using a suit-
able ohmmeter per the appropriate motor specifica-
tion. Verify that the field is electrically isolated from
the frame using a dielectric tester. Replace as neces-
sary.
5. Visually inspect the armature (2) assembly for signs
of overheating or physical damage. Visually inspect
the seal surface of the shaft for excessive wear.
Check for grounded circuits using a dielectric tester
by applying voltage between the commutator and
the shaft. Visually inspect the commutator for exces-
sive wear and overheating. Replace as necessary.
6. Visually inspect the brake surfaces for excessive
wear. Remove any RTV Silicone sealant that may be
present on the friction disc, cover, or commutator
end head. Replace brake assembly (11) if neces-
sary.
7. Visually inspect the wire harness (8) for frayed insu-
lation, loose terminals, or other damage. Replace as
necessary.
Figure 4-6. Drive Motor Side View Figure 4-7. Drive Motor End View (Brake End)