Preventive Maintenance - Lincoln Electric Invertec STT II Operator's Manual

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PREVENTIVE MAINTENANCE

1. Perform the following preventive mainte-
nance procedures at least once every six
months. It is good practice to keep a pre-
ventive maintenance record; a record tag
attached to the machine works best.
2. Remove the machine wraparound cover
and perform the input filter capacitor dis-
charge procedure (detailed at the begin-
ning of this chapter).
3. Clean the inside of the machine with a
low pressure airstream. Be sure to clean
the following components thoroughly.
• Power Switch, Driver, Protection, and
Control printed circuit boards
• Power Switch
• Main Transformer
• Input Rectifier
• Heat Sink Fins
MAINTENANCE
INVERTEC STT II
• Input Filter Capacitors
• Output Terminals
• Lower base compartment
4. Examine capacitors for leakage or ooz-
ing. Replace if needed.
5. Examine wraparound cover for dents or
breakage. Repair as needed. Cover
must be kept in good condition to assure
high voltage parts are protected and cor-
rect spacings are maintained.
6. Check electrical ground continuity. Using
an ohmmeter, measure resistance
between either output stud and an
unpainted surface of the machine case.
Meter reading should be 500,000 ohms
or more. If meter reading is less than
500,000 ohms, check for electrical com-
ponents that are not properly insulated
from the case. Correct insulation if need-
ed.
7. Replace machine cover and screws.
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