Protection 1; Switch 2; Power; Input Rectifier 1 - Lincoln Electric INVERTEC V300-PRO SVM105-B Service Manual

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PREVENTIVE MAINTENANCE
1. Perform the following preventive maintenance
procedures 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 wrap-around cover and per-
form the input filter capacitor discharge procedure
(detail 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. See Figure D.2 for loca-
tion of these components.
• Power Switch, Driver, Protection, and Control
printed circuit boards
• Power Switch
• Main Transformer
• Input Rectifier
• Heat Sink Fins
• Input Filter Capacitors
• Output Terminals
4. Examine capacitors for leakage or oozing.
Replace if needed.
5. Examine wrap-around cover for dents or break-
age. 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. (See Figure D.2 for locations.) Meter read-
ing should be 500,000 ohms or more. If meter
reading is less than 500,000 ohms, check for
electrical components that are not properly insu-
lated from the case. Correct insulation if needed.
7. Replace machine cover and screws.
MAINTENANCE
OVERLOAD PROTECTION
The machine is electrically protected from producing
high output currents. Should the output current
exceed 340-360A, an electronic protection circuit will
reduce the current ("Fold Back") to approximately
150A. The machine will continue to produce this low
current until the protection circuit is reset. Reset
occurs when the output load is removed.
THERMAL PROTECTION
Thermostats protect the machine from excessive
operating temperatures. Excessive temperatures
may be caused by a lack of cooling air or operating
the machine beyond the duty cycle and output rat-
ing. If excessive operating temperature should
occur, the thermostat will prevent output voltage or
current. The meter will remain energized during this
time.
PC BOARD REPLACEMENT
1. Handle PC Boards by edges only.
2. Store PC Boards only in the bags that disperse
static charges.
3. Inspect PC Board for burned conductors or com-
ponents. If damage is visible, inspect the
machine wiring for grounds or shorts to avoid
damaging a new PC Board.
4. If there is no visible damage to the PC Board,
install a new PC Board and see if the problem is
fixed. If the problem is fixed by the new board,
reinstall the old board and see if the problem
reoccurs. If the problem does not reoccur, check
the wiring harness and plugs for loose connec-
tions.
V300-PRO
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