Lincoln Electric IM904 manual Maintenance, Input Filter Capacitor Discharge Procedure

D-1 MAINTENANCE D-1

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.

INVERTEC STT II (CE)