Output Choke Test Procedure - Lincoln Electric Classic 300 MP Service Manual

LINCOLN ELECTRIC

OUTPUT 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 Output Choke is functioning normally.
MATERIALS NEEDED
1/2" Open-End Wrench
1/2" Nutdriver
Volt/ohmmeter
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Classic 300 MP machine.
2. Perform the Case Cover Removal Procedure.
3. Locate the output choke. See Figure F.14. See Wiring Diagram.
4. Inspect the windings and connections for signs of burning or overheating.
5. Using a 1/2" open-end wrench and 1/2" nutdriver, remove the nut, washer and bolt securing the
heavy leads to the top and bottom output choke terminals. Label and disconnect leads from the
terminals. See Figure F.15. See Wiring Diagram.
6. Using a volt/ohmmeter, measure the resistance of the choke windings. Normal resistance should be
less than one ohm. See Wiring Diagram.
7. Using a volt/ohmmeter, measure the resistance from the windings to ground. Normal resistance
should be greater than 500k ohms (high resistance).
8. If any of the tests fail, the output choke may be faulty.
9. If faulty, perform the Output Choke Removal And Replacement Procedure.
10. When testing is complete, connect the previously disconnected leads to the choke terminals.
11. Perform the Case Cover Replacement Procedure.
Classic® 300 MP Service Manual
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