Contactor Test Procedure - Lincoln Electric LN-25x Service Manual

LINCOLN ELECTRIC

CONTACTOR 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 procedure will help determine if the Contactor is functioning properly.
MATERIALS NEEDED
Volt/Ohmmeter
12 VDC External Power Supply
Wiring Diagram
TEST PROCEDURE
1. Remove the input power to the LN-25x wire feeder.
2. Perform the Wire Drive Assembly And Control Box Cover Removal Procedure.
3. Locate the contactor. See Figure F.12. See Wiring Diagram.
4. Label and disconnect the black contactor coil leads #578 and #507 from the harness. See Figure
F.13. See Wiring Diagram.
5. Using a volt/ohmmeter, measure the resistance of the contactor coil. The resistance should be
approximately 4-5 ohms. See Wiring Diagram.
6. Using a 12 VDC external power supply, carefully apply 12 VDC to the black contactor coil leads. See
Figure F.13. The contactor should activate with a loud "click".
7. With the contactor activated the resistance across the contactor's terminals should be zero ohms.
8. When the contactor is not activated the resistance across the contactor's terminals should be very
high (500,000 ohms).
9. If the contactor passes the above tests, replace any previously disconnected leads and perform the
Wire Drive Assembly And Control Box Cover Replacement Procedure.
10. If any of the tests fail, the contactor may be faulty.
11. If faulty, perform the Contactor Removal and Replacement Procedure.
LN-25x™ Service Manual
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