JLG 1230ES Service And Maintenance Manual Download

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SECTION 4 - BASE COMPONENTS

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– JLG Lift –

4-11

4.8

WHEEL DRIVE ASSEMBLY - SERVICING

The component parts of the left and right drive motor
assemblies are identical. The left drive motor is run in the
reverse direction of the right motor.

for details on the traction system electrical theory of operation
see section 4.

Drive Motor Electrical Evaluation

Several basic electrical tests can be performed on the
Drive Motors. Failure of one of these evaluations is signifi-
cant and may indicate that the device is physically dam-
aged.

Make all measurements with a voltmeter set to resistance
scale (Ohms). Disconnect the Main Battery Disconnect
and all drive motor cables during this analysis.

1. Resistance < 2 Ohms Red to Black Armature

Wires.

The heavy red and black conductors are con-
nected to the motor's armature winding. The
winding is a very low impedance and should
appear to be a short-circuit for an ordinary volt-
meter (other tests can determine if the armature
is truly shorted). High resistance can signal cor-
rosion, improper crimps, damaged cabling, worn
brushes, a faulty commutator, or an open arma-
ture winding.

2. Resistance < 2 Ohms Blue to Orange Field

Wires.

The blue and orange conductors are connected
to the motor's field winding. In order to make
this measurement, it will be necessary to discon-
nect the butt-splice on the two orange wires or
use a piercing meter probe. As with the arma-
ture, the field is a very low impedance and
should appear to be a short-circuit for an ordi-
nary voltmeter. High resistance can signal corro-
sion, improper crimps, damaged connectors,
damaged cabling, or an open field winding.

3. Resistance 15-25 Ohms Yellow to Brown

Brake Wires.

The yellow and brown wires are connected to
the integral brake. Improper resistance can sig-
nal corrosion, improper crimps, damaged
cabling, or a fault solenoid.

4. Resistance > 1 mOhm Red Armature Wire to

Motor Housing.

The armature winding should be electrically iso-
lated from the motor housing. Low resistance
may be an indication of a crushed cable, a
burned cable, or a burned armature winding.
Investigate by disconnecting the drive motor
cable from the motor and re-measure resistance
(isolation).

5. Resistance > 1 mOhm Blue Field Wire to

Motor Housing.

The field winding should also be electrically iso-
lated from the motor housing. Low resistance
may be an indication of a crushed cable, a
burned cable, or a burned field winding. Investi-
gate by disconnecting the drive motor cable
from the motor and re-measure resistance (isola-
tion).

6. Resistance > 1 mOhm Red Armature Wire to

Blue Field Wire.

The armature and field windings should also be
electrically isolated from one another. Low resis-
tance may be an indication of a crushed cable, a
burned cable, damaged windings. Investigate
by disconnecting the drive motor cable from the
motor and re-measure resistance (isolation).