Lincoln Electric IM663 RED-D-ARC D300K 3+3 - Manual (Page 23)

E-2 TROUBLESHOOTING E-2
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 Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
PROBLEMS
(SYMPTOMS)
POSSIBLE
CAUSE
RECOMMENDED
COURSE OF ACTION
Machine fails to hold the heat con-
sistently.
Welder starts but fails to generate
current.
1. Rough or dirty commutator.
Commutator should be turned or
cleaned.
2. Brushes may be worn down to
limit. Replace brushes.
3. Field circuit may have variable
resistance connection or intermit-
tent open circuit due to loose con-
nection or broken wire. Check
field current with ammeter to dis-
cover varying current. This applies
to both the main generator and
exciter.
4. Electrode lead or work lead con-
nection may be poor. Tighten all
connections.
5. Wrong grade of brushes may
have been installed on generator.
Use proper brushes.
6. Field rheostat may be making
poor contact and overheating.
Inspect and clean the rheostat.
1. Generator or exciter brushes may
be loose or missing. Be sure that
all brushes bear on the commuta-
tor and have proper spring ten-
sion.
2. Exciter may not be operating.
Check exciter output voltage with
voltmeter or lamp.
3. Field circuit of generator or exciter
may be open.
Check for open circuits in rheo-
stat, field leads, and field coils.
Check rectifier bridge and fuses.
4. Exciter may have lost excitation.
Flash fields. (1) Check flashing
diode at 5 oʼclock brush holder in
generator.
5. Series field and armature circuit
may be open-circuited. Check cir-
cuit with ringer or voltmeter.
If all recommended possible areas of
misadjustment have been checked
and the problem persists, Contact
your local Authorized Field
Service Facility.
D300K 3+3
WELDER TROUBLESHOOTING