Lincoln Electric IM869-D - Manual (Page 25)

E-2 TROUBLESHOOTING E-2
SAE-400
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local
Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
FUNCTION PROBLEMS
PROBLEMS
(SYMPTOMS)
POSSIBLE
CAUSE
RECOMMENDED
COURSE OF ACTION
Machine fails to hold the “heat”
constantly. 1. Rough or dirty commutator.
2. Brushes may be worn down to
limit of life.
3. Brush springs may be broken.
4. Field circuit may have variable
resistance connections or inter-
mittent open circuit, due to loose
connections or broken wire.
5. Electrode or work lead connec-
tions may be poor.
6. Wrong grade of brushes may be
installed on generator.
7. Field rheostat may be making
poor contact and overheating.
8. “Current Control” may not be
operating properly.
9. “Current Control” brushholder
contact springs may be worn out
or missing. Contact surface may
be dirty, rough and pitted.
10. “Current Control” brushholder
support stud and mating contact
surfaces may be dirty or pitted
and burned.
11. Engine running at varying
speeds.
1. True and clean commutator.
2. Replace brushes.
3. Replace brush springs.
4. Check field current with ammeter
to discover varying current. This
applies to both the main genera-
tor and exciter.
5. Tighten all connections.
6. Use only the recommended
Lincoln brushes.
7. Inspect and clean rheostat.
8. Check for loose or missing set
screw in control handles.
9. Inspect. Replace needed parts.
Clean internal contact surface of
control device. Do not lubricate.
Smooth rough surfaces.
10. If brushholder internal contact
surface is pitted and burned,
replace the brushholder and
support stud. If the contact sur-
face is dirty, clean off the brush-
holder stud and internal contact
surface. Apply mixture of three
parts silicone grease and one
part zinc powder (by weight) to
stud.
11. Set welder controls for maximum
output and weld. Then, while
welding, check engine rpm. The
engine should be running at full
speed. If indicator shows a sig-
nificant difference, consult your
engine manual.