Lincoln Electric IM904 INVERTEC STT II - Manual (Page 22)

D-1 MAINTENANCE D-1
INVERTEC STT II (CE)
WARNING
Failure to follow this capacitor
discharge procedure can result
in electric shock.
INPUT FILTER CAPACITOR
DISCHARGE PROCEDURE
1. Turn off input power or disconnect input power
lines.
2. Remove hex head screws from side and top of
machine and remove wrap-around machine cover.
3. Be careful not to make contact with the capacitor
terminals that are located in the center of the
Switch Boards.
4. Obtain a high resistance and high wattage resistor
(25-1000 ohms and 25 watts minimum). This resis-
tor is not supplied with machine. NEVER USE A
SHORTING STRAP FOR THIS PROCEDURE.
5. Locate the two capacitor terminals (large hex head
cap screws) shown in Figure
D.1.
6. Use safety glasses, electrically insulated gloves
and insulated pliers. Hold body of the resistor and
connect resistor leads across the two capacitor ter-
minals. Hold resistor in place for 10 seconds. DO
NOT TOUCH CAPACITOR TERMINALS WITH
YOUR BARE HANDS.
7. Repeat discharge procedure for capacitor on other
side of machine.
8. Check voltage across terminals of all capacitors
with a DC voltmeter. Polarity of capacitor terminals
is marked on PC board above terminals. Voltage
should be zero. If any voltage remains, repeat this
capacitor discharge procedure.
FIGURE D.1 — LOCATION OF INPUT FILTER CAPACITOR TERMINALS.