The arc is unstable and or "hunting, The contact tip seizes in the gas diffuser, Troubleshooting & repair – Lincoln Electric WIRE-MATIC 255 SVM 119-A Manuel d'utilisation
Page 59: Caution
F-8
TROUBLESHOOTING & REPAIR
F-8
WIRE-MATIC 255
TROUBLESHOOTING GUIDE - Observe all Safety Guidelines detailed throughout this manual
WELDING PROBLEMS
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENTS(S)
RECOMMENDED
COURSE OF ACTION
The arc is unstable and or "hunting".
Weld bead is narrow or ropy. May
have porosity with electrode stub-
bing into plate.
The contact tip seizes in the gas dif-
fuser.
1.
Check for loose connections at
the output terminals, the choke,
the capacitor bank and all heavy
current carrying leads.
2.
Make sure that the transformer
secondary leads are securely
connected to the SCR Rectifier
Assembly.
3.
The output capacitor bank may
be faulty. Check for loose con-
nections at the capacitors. Also
check for leaky capacitors.
Replace if necessary.
WARNING: The liquid elec-
trolyte in these capacitors is
toxic. Avoid contact with any
portion of your body.
4.
The control board may be faulty.
Replace
1.
The output capacitor bank may
be faulty. Check for loose con-
nections at the capacitors. Also
check for leaky capacitors.
Replace if necessary.
WARNING: The liquid elec-
trolyte in these capacitors is
toxic. Avoid contact with any
portion of your body.
2.
The control board may be faulty.
Replace.
1.
Check for worn or melted con-
tact tip.
2.
Check for loose or faulty con-
nections on the work and elec-
trode cables.
3.
Make sure electrode polarity is
correct or welding process
being used.
4.
Check for rusty or dirty wire.
5.
Make sure machine settings
and gas are correct for process
being used.
1.
Make sure the weld procedure
and electrode polarity is correct
for the process being used.
2.
Make sure shielding gas is cor-
rect and flow is proper.
3.
Make sure the weld joint is not
"contaminated".
1.
The tip being over heated due to
excessive current and/or high
duty cycle welding.
2.
A light application of high tem-
perature antisieze lubricant
(such as Lincoln E2607
Graphite Grease) may be
applied to the contact tip
threads.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, con-
tact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed call 216-
383-2531 or 1-800-833-9353
CAUTION