Choke Test Procedure - Lincoln Electric Cross Country 300 Service Manual

LINCOLN ELECTRIC
CHOKE TEST PROCEDURE
Service and repair should be performed by only Lincoln Electric factory trained personnel. Unauthorized
repairs performed on this equipment may result in danger to the technician or machine operator and will
invalidate your factory warranty. For your safety and to avoid electrical shock, please observe all safety
notes and precautions detailed throughout this manual. If for any reason you do not understand the test
procedures or are unable to perform the test/repairs safely, contact the Lincoln Electric Service Department
for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.
TEST DESCRIPTION
This test will determine if the Choke is shorted turn to turn or grounded.
MATERIALS NEEDED
7/16" Nutdriver
Volt/Ohmmeter
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Cross Country 300 machine.
2. Perform the Case Cover Removal Procedure.
3. Perform the Capacitor Discharge Procedure.
4. Locate the chopper module board. See Figure F.23. See Wiring Diagram.
5. Using a 7/16" nutdriver, remove the bolt, lock washer and flat washer securing the heavy lead to
terminal B6 of the chopper module. See Figure F.23. See Wiring Diagram.
6. Open: No weld output. Using a volt/ohmmeter, measure the resistance from the heavy lead to the
negative CV output terminal. See Figure F.24. See Wiring Diagram. Resistance should be very low
(less than one ohm). Using a volt/ohmmeter, measure the resistance from the heavy lead to the
negative CC output terminal. See Figure F.24. See Wiring Diagram. Resistance should be very low
(less than one ohm).
7. Turn To Turn Short: Reduced inductance, arc instability, excessive heating of the choke. Check for
any physical signs of arcing within the choke assembly.
8. Choke Coil Grounded: Reduced inductance, alternate weld current path. Using a volt/ohmmeter,
measure the resistance from the heavy choke lead (B6 on the chopper module board) to chassis
ground. Resistance should be at least 500,000 (500k ohms). See Wiring Diagram.
9. If any of the tests fail, the choke may be faulty.
10. If faulty, perform the Choke Removal And Replacement Procedure.
11. Using a 7/16" nutdriver, attach the bolt, lock washer and flat washer securing the heavy lead to
terminal B6 of the chopper module. See Wiring Diagram.
12. Perform the Case Cover Replacement Procedure.
Cross Country™ 300 Service Manual
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