Lincoln LT-7, Troubleshooting Manual

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TROUBLESHOOTING AND REPAIR
B-27 B-27
LT-7 TRACTOR
TEST POINTS RESISTANCE DC VOLTAGE
Lead #594 to #595 25 ohms 0 to 90VDC
Armature
Lead #559 to #561 27 ohms* 0 to 90VDC*
Armature*
Lead #546 to #547 500 to 650 ohms* 90 TO 110VDC*
Field Winding*
All leads to motor 500,000 ohms min. NONE
shell
TABLE B.4
*DENOTES OLDER UNITS WITH FIELD WINDING
TRAVEL MOTOR TEST ( continued)
TEST PROCEDURE
1. Remove the travel motor connector from
the LT7 control box.
2. Using the ohmmeter measure the motor
resistances per Table B.4. Also see
Figures B.5. and B.6*
3. If the motor resistance test is good pro-
ceed to the Motor Applied Voltage Test.
MOTOR APPLIED VOLTAGE TEST
1. *Carefully connect the 110VDC supply
(SUPPLY TURNED OFF) to pins C and D
on the travel motor connector. See Figure
B.6
2. Carefully connect the variable 0 to 90VDC
supply (SUPPLY TURNED OFF) to pins A
and B on the travel motor connector.
3. *Apply field voltage first (pins C and D) to
the motor. See Figure B.6 and Table B.4
4. Slowly apply the armature voltage on pins
A and B.(See Table B.4)
5. The motor should run and the speed
should vary with changes to the armature
voltage.
6. If the travel motor does NOT run and
change speed correctly the motor or gear
box may be faulty.
7. *To stop motor REMOVE ARMATURE
VOLTAGE FIRST. (Pins A and B)
*DENOTES OLDER UNITS WITH FIELD
WINDING