Lincoln Electric INVERTEC POWER WAVE 450 SVM112-B Service Manual page 266

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PRE-POWERUP SWITCH BOARD TEST PROCEDURE
FOR REPLACEMENT OF SWITCH ASSEMBLY G2402-2 (continued)
460VAC RECONNECT
1. Reconfigure the machine for 460VAC operation.
2. Turn ON the variable AC supply applied to the
primary circuit. See Figure F.76.
3. Turn on the arc start switch. See Arc Start
PW450 or Figure F.79.
4. Slowly increase the voltage until filter capacitor
voltage is 25VDC. NOTE: Monitor both capaci-
tor voltages. If the two voltages are not within 5
to 8 VDC of each other STOP and check wiring
to the FET switch board assembly and also the
individual switch boards. See Figure F.77.
5. Adjust the grid load to get 5 amps output from
the Power Source.
THAN 7-8 AMPS OUTPUT FROM THE
POWER WAVE.
6. Repeat the previous Snubber Signal Test by
checking the eight test points.
OUTPUT SIGNAL TEST
1. Make certain the machine is configured for
460VAC operation.
2. Turn ON the variable AC supply applied to the
primary circuit. See Figure F.76.
3. Turn ON the arc start switch. See Arc Start
PW450 or Figure F.79.
TROUBLESHOOTING & REPAIR
FIGURE F.82 - SNUBBER SIGNAL
5V/Div
DO NOT PULL MORE
POWER WAVE 450
0 V
20uS/Div
4. Slowly increase the voltage until the filter capac-
itor voltage is 25VDC. See Figure F.77.
5. Adjust the grid load to get 5 amps output from
the Power Wave. DO NOT DRAW MORE
THAN 7-8 AMPS OUTPUT FROM THE
POWER WAVE.
6. Set the Oscilloscope for:
5 V/div.
10 uS/div.
WARNING
ALL METERS AND OSCILLOSCOPES MUST BE
ELECTRICALLY ISOLATED.
7. Connect the positive oscilloscope probe to the
Power Wave positive welding output terminal
and the negative probe to the negative welding
output terminal. The output should look like the
oscilloscope picture in Figure F.83.
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