Lincoln Electric INVERTEC IM904 - Manual (Page 23)

D-2 MAINTENANCE D-2
INVERTEC STT II (CE)
PREVENTIVE MAINTENANCE
1. Perform the following preventive maintenance pro-
cedures at least once every six months. It is good
practice to keep a preventive maintenance record;
a record tag attached to the machine works best.
2. Remove the machine wraparound cover and per-
form the input filter capacitor discharge procedure
(detailed at the beginning of this chapter).
3. Clean the inside of the machine with a low pres-
sure 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
• Input Filter Capacitors
• Output Terminals
• Lower base compartment
4. Examine capacitors for leakage or oozing. 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 correct spacings are maintained.
6. Check electrical ground continuity. Using an ohm-
meter, 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 components that are not prop-
erly insulated from the case. Correct insulation if
needed.
7. Replace machine cover and screws.