E-2

 

TROUBLESHOOTING

E-2

 

 

 

 

 

Observe all Safety Guidelines detailed throughout this manual

 

 

 

 

 

PROBLEMS

POSSIBLE

RECOMMENDED

 

(SYMPTOMS)

CAUSE

COURSE OF ACTION

 

 

 

 

FUNCTION PROBLEMS

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.

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.

SAE-400

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Lincoln Electric IM869-D manual Symptoms, Course of Action