Lincoln Electric SAE-300 HE, Service Manual, Page: 46 / 84

LINCOLN ELECTRIC SAE-300® HE Service Manual
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SHUNT FIELD CIRCUIT VOLTAGE 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 determine if the Shunt Field Coils are receiving the necessary power to operate
correctly.
This test should be done if there is little or no output from the welding generator, but auxiliary output is
normal.
MATERIALS NEEDED
Volt/Ohmmeter
Wiring Diagram
TEST PROCEDURE
1. Turn off the engine on the SAE-300 HE machine.
2. Locate the 12-pin Molex connector in the wire bundle that exits the welding generator fame. See
Wiring Diagram.
3. Set the voltmeter for DC voltage and back probe pins #3 and #5, (blue and brown wires) of the 12-
pin Molex connector.
4. Set the fine current / OCV control to maximum, set the idle switch to “High” and set the
remote/local switch to local position.
5. Start the engine.
6. The voltage should read about 123 to 133 Volts DC (Voltage will be a bit higher if machine is not
warmed to normal operating temperature).
If normal DC voltage is present, perform the Shunt Field Coil Resistance and Ground Test
Procedure .
If voltage is not present, check the rheostat, the remote/local switch, the J5 and P10 Molex
connectors. Check all the wiring and terminals connecting the field bridge rectifier, the remote /
local switch, the flashing/flywheel rectifier and the J5 - P10 connectors.