12
Pulse Verification Procedure
The following procedure will verify that the high voltage pulse is properly generated by the MegaPulse tester. We
recommend that this procedure be conducted periodically to ensure proper operation of the tester.
The following items are needed to conduct this procedure:
•
High voltage oscilloscope probe (100:1)
•
Digital Oscilloscope
•
Current probe
Always ensure that the measuring instruments are rated for the voltage and frequency response involved. A digital
oscilloscope or probe with a low frequency response will result in erroneous readings that could be misread.
CAUTION
High voltage generated by the MegaPulse tester is exposed during this test. A risk of shock exists.
Exercise care when using the MegaPulse tester.
1.
Turn the rear-panel Power Switch OFF.
2.
Disconnect all high voltage cables from the output.
3.
Turn the rear-panel Power Switch ON. If residual voltage is shown on LED display:
a.
Press the red
TRIGGER
button to discharge the main capacitor into the internal resistor of the
MegaPulse unit.
4.
Set the Voltage Set Point to 500V, see section “Voltage Set Point Adjustment.”
5.
Plug the high voltage test lead (black) into the Return jack, located on the front panel.
6.
Plug the high voltage test lead (red) into the output jack, located on the front panel.
7.
Connect the ends of the test leads to the measuring instrument. See Figure 4 for an example.
8.
Set the next capturing setting on the digital oscilloscope to capture the high voltage pulse:
a.
Vertical Scale = 100V / div.
b.
Horizontal Scale = 10uS / div
c.
Trigger Level = +100V
d.
Slope transition “Low to High.”
e.
Set “High Frequency Reject” mode.
f.
Set “Single Pulse” capture mode.
9.
Press the Charge button and wait until voltage reaches 500V.
10.
Press the Trigger button to deliver the pulse (be sure not to touch the output and return leads when pressing
the trigger switch).
11.
Verify that the impulse waveform obtained complies with the tester specs in
Section 3
.
12.
Repeat steps 8 through 11 at 2000V, be sure to adjust oscilloscope settings to capture the full waveform.
13.
Select a negative pulse by pressing the polarity button, and verify the yellow REV indicator is lit.
14.
Change the capturing setting on the digital oscilloscope to capture the negative pulse:
a.
Trigger Level = -100V.
b.
Slope transition “High to Low”
15.
Charge and Trigger the pulse at 500V. `
16.
Verify that the impulse waveform obtained complies with the tester specs in
Section 3
.
*Image for reference only.
Figure 3. Waveform Measurement Setup
.
