Lincoln Electric Fleet 400 Service Manual page 12

LINCOLN ELECTRIC
Observe Safety Guidelines
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The machine will weld but the
welding arc is "COLD". The
engine runs normally and the
auxiliary power is normal.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Make sure the machine is
properly set for the electrode
and process being used. Check
electrode size, mode switch
setting and amps or voltage
setting.
2. Make sure the process does
not demand more power than
the machine can produce.
3. If the current is correct try
increasing the "ARC FORCE"
setting.
4. Check for loose or faulty
connections at the weld output
terminals and welding cable
connections.
5. Check for good connections
between the work cable and
the work piece.
6. The weld cables may be too
long or too small of a diameter
causing excessive voltage drop.
7. The weld cables should not
be coiled or wrapped around
metal racks or reels. This can
cause excessive inductance in
the weld circuit. Try welding
with a short set of adequately
sized weld cables.
Fleet™ 400 Service Manual
TROUBLESHOOTING GUIDE
RECOMMENDED
COURSE OF ACTION
1. Disconnect all external
equipment and perform a
"load" test using a resistive
load bank and accurate meters.
Adjust the load for
approximately 400 Amps at 25
Volts; check that the engine
speed holds at 1800 rpm. If not
perform engine maintenance.
If the Fleet 400 has meters,
make sure that they read the
same as the load bank meters.
If not, perform the Weld
Control Board Feedback Test
Procedure.
2. If the maximum weld output
cannot be obtained, check for
damaged conductors or loose
connections in the large current
carrying conductors of the
stator, output rectifier bridge,
chopper module board, choke,
shunt and output terminals.
See Wiring Diagram.
3. If all these connections are
good, perform the Stator
Voltage Test Procedure, the
Output Rectifier Bridge Test
Procedure and the Chopper
Module Board Resistance Test
Procedure.
4. Perform the Output Control
And Arc Force Potentiometer
Test Procedure.
5. Perform the Choke Test
Procedure.
6. Perform the Pipe/Gouge
Range Switch And Weld Mode
Switch Test Procedure.
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