| TROUBLESHOOTING |
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| Observe all Safety Guidelines detailed throughout this manual |
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| PROBLEMS | POSSIBLE CAUSE | RECOMMENDED |
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| (SYMPTOMS) | COURSE OF ACTION |
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FUNCTION PROBLEMS
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.
CAUTION
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.
SAE400 & SAE400 WELD’N AIR
