Troubleshooting & repair – Lincoln Electric INVERTEC POWER WAVE 450 SVM112-B User Manual

Page 268

TROUBLESHOOTING & REPAIR

F-208

POWER WAVE 450

PRE-POWERUP SWITCH BOARD TEST PROCEDURE

FOR REPLACEMENT OF SWITCH ASSEMBLY G2402-2 (continued)

5. Press the MANUAL PROCEDURE ENTRY

Key on the Calibration and Test Overlay and
change the Power Wave to “Process 1 Setup 1
-8” mode.

6. Turn the arc start switch ON. See Arc Start

PW450 or Figure F.79.

7. Adjust the output grid load to get 400 amps at

36VDC. The oscilloscope picture should look
like Figure F.84.

*ALTERNATE TEST (without current probe)
1. Connect a transformer isolated oscilloscope

as follows:

Set oscilloscope for .2v/div and 10us/div
Probe

J21 pin 1 wire #211

Common J21 pin 5 wire #215

2. Observe a waveform similar to Figure F.84.

Equal amplitude and symmetry of the pulses is
important.

3. Check the capacitor voltages. The capacitor

voltages must be within eight volts of each
other.

4. Turn the arc start switch OFF. See Arc Start

PW450 or Figure F.79

5. Turn OFF the Power Wave and remove the

input power. Make sure the filter capacitors are
completely discharged. See Figure F.77.

PREPARE MACHINE FOR NORMAL
OPERATION.
1. Turn the power switch OFF and remove input

power to the machine.

2. The input capacitors must be discharged

before continuing.

3. Remove the capacitor voltage monitoring

leads. See Figure F.77.

4. Remove the power input cable from CR1.

5. Remove the output cables from the Power

Wave.

6. Remove the arc start switch circuit.

7. Enable the water cooler if it was enabled at the

start of this test.

FIGURE F.84 - PRIMARY CURRENT SIGNAL

0 V

10V/Div

10uS/Div