Lincoln Electric IM581 SAE400 - Manual (Page 24)

E-2 TROUBLESHOOTING E-2
SAE400 WELD’N AIR
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. Rough or dirty commutator.
Brushes may be worn down to limit
of life.
Brush springs may be broken.
Field circuit may have variable resis-
tance connections or intermittent
open circuit, due to loose connec-
tions or broken wire.
Electrode or work lead connections
may be poor.
Wrong grade of brushes may be
installed on generator.
Field rheostat may be making poor
contact and overheating.
“Current Control” may not be operat-
ing properly.
“Current Control” brushholder con-
tact springs may be worn out or
missing. Contact surface may be
dirty, rough and pitted.
“Current Control” brushholder sup-
port stud and mating contact sur-
faces may be dirty or pitted and
burned.
Engine running at varying speeds.
True and clean commutator.
Replace brushes.
Replace brush springs.
Check field current with ammeter to
discover varying current. This
applies to both the main generator
and exciter.
Tighten all connections.
Use only the recommended Lincoln
brushes.
Inspect and clean rheostat.
Check for loose or missing set screw
in control handles.
Inspect. Replace needed parts.
Clean internal contact surface of
control device. Do not lubricate.
Smooth rough surfaces.
If brushholder internal contact sur-
face is pitted and burned, replace
the brushholder and support stud. If
the contact surface is dirty, clean off
the brushholder stud and internal
contact surface. Apply mixture of
three parts silicone grease and one
part zinc powder (by weight) to stud.
Set welder controls for maximum
output and weld. Then, while weld-
ing, check engine rpm. The engine
should be running at full speed. If
indicator shows a significant differ-
ence, consult your engine manual.