Lincoln Electric 350-SA manual Trouble Cause What to do

TROUBLESHOOTING

TROUBLE	CAUSE		WHAT TO DO
A. Machine fails to hold the “heat”	1.	Rough or dirty commutator.	1.	Commutator should be turned
consistently.				or cleaned.
	2.	Brushes may be worn down to	2.	Replace brushes.
		limit.
	3.	Field circuit may have variable	3.	Check field current with ammeter
		resistance connection or		to discover varying current. This
		intermittent open circuit due to		applies to both the main
		loose connection or broken wire.		generator & the exciter.
	4.	Electrode lead or work lead	4.	Tighten all connections.
		connection may be poor.
	5.	Wrong grade of brushes may	5.	Use Lincoln brushes.
		have been installed on
		generator.
	6.	Field rheostat may be making	6.	Inspect & clean the rheostat.
		poor contact and overheating.
B. Welder starts but fails to	1.	Generator or exciter brushes	1.	Be sure that all brushes bear on
generate current.		may be loose or missing.		the commutator and have proper
				spring tension.
	2.	Exciter may not be operating.	2.	Check exciter output voltage
				with voltmeter or lamp.
	3.	Field circuit of generator or	3.	Check for open circuits in
		exciter may be open.		rheostat, field leads and field
				coils. Check rectifier bridge.
	4.	Exciter may have lost excitation.	4.	Flash fields. (1)
	5.	Series field and armature circuit	5.	Check circuit with ringer or
		may be open-circuited.		voltmeter.
C. Welding arc is loud and	1.	Current setting may be too high.	1.	Check setting and current output
spatters excessively.				with ammeter.
	2.	Polarity may be wrong.	2.	Check polarity. Try reversing
				polarity or try an electrode of the
				opposite polarity.

(1)See FLASHING THE FIELDS on following page.

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