Taylor-Dunn ET-015-00, Operation, T Roubleshooting And Replacement Parts Manual

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Maintenance, Service, and Repair
Electrical Troubleshooting
Page 8
Motor Windings
Disconnect both of the battery leads during any maintenance or
before disconnecting any electrical component or wire. Failure to do
so may cause severe bodily injury and/or property damage.
The test equipment required to fully test a motor is very expensive. The test procedure provided here
will be able to diagnose the most common motor failure modes. Most other failure modes can be
diagnosed by analyzing the symptoms of the running motor in the vehicle.
Disconnect the batteries.
Disconnect all 4 wires from the motor.
Symptoms:
NOTE: Before diagnoses of motor using symptoms,
confirm that the vehicle control system is
functioning correctly.
Vehicle runs slow or lack of power:
Most likely due to shorted armature or
field windings. This will also be
accompanied with extremely high
motor current.
Vehicle shudders or vibrates at low motor RPM:
Most likely due to open or shorted
armature windings. This may also be
accompanied with extremely high
motor current.
Intermittent running, sparking in motor:
Most likely due to worn or damaged motor
brushes. During intermittent failed
condition, will also have open armature
windings.
“Clicking” noise from motor:
Most likely due to one or more raised
commutator segments. This could be a
result of a damage due to a stalled
condition. If not accompanied with
other symptoms it may be repaired by
cutting the armature on a lathe.
Windings:
Test continuity from the motor A1 terminal to the
A2 terminal.
> Should read as a short circuit (0
Ohms).
If not 0 Ohms, then the armature winding
is open. Repair or replace the motor.
Test continuity from the motor S1 terminal to the
S2 terminal.
> Should read as a short circuit (0
Ohms).
If not 0 Ohms, then the field winding is
open. Repair or replace the motor.
Test continuity from the motor S1 terminal to the
A2 terminal.
> Should read as a open circuit.
If not open, then the windings are shorted,
Repair or replace the motor.
Test continuity from the motor A1 terminal to the
motor housing.
> Should read as a open circuit.
If not open, then the armature winding is
shorted, Repair or replace the motor.
Test continuity from the motor S1 terminal to the
motor housing.
> Should read as a open circuit.
If not open, then the field winding is
shorted, Repair or replace the motor.
These test procedures must be
performed in the order they were
written. If the test result is good,
then proceed to the next test or go
to the next section. Failure to do so
may result in incorrect test results.