Choke Test Procedure - Lincoln Electric Fleet 650 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 either of the Chokes are open, shorted (turn to turn) or grounded.
MATERIALS NEEDED
Volt/Ohmmeter
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the Fleet 650 machine.
2. Perform the Case Cover Removal Procedure.
3. Perform the Chopper Module Capacitor Discharge Procedure.
4. Locate the two choke assemblies and perform the following test on each choke assembly. See
Figure F.24. See Wiring Diagram.
5. Open: No weld output. Using a volt/ohmmeter, test the resistance from the B3/B6-Choke lead to
the negative output terminal. See Figures F.24 and F.25. See Wiring Diagram. Typical resistance is
less than one ohm.
6. Turn To Turn Short: Reduced inductance, arc instability, excessive heating of the choke. Check for
any physical signs of arcing within the choke assembly. See Wiring Diagram.
7. Choke Coil Grounded: Reduced inductance, alternate weld current path. Electrically isolate the
choke coil by disconnecting the leads B3-Choke and B6-Choke from the chopper board and the
heavy choke lead from the negative output terminal. Using a digital volt/ohmmeter, check the
resistance from choke coil to chassis ground. Resistance should be at least 500,000 ohms. See
Wiring Diagram.
8. If any of the tests fail, the choke may be faulty.
9. If faulty, perform the Choke Removal And Replacement Procedure.
10. Connect any previously disconnected leads. See Wiring Diagram.
11. Perform the Case Cover Replacement Procedure.
Fleet™ 650 Service Manual
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