Compliance West MegaPulse, Инструкция по эксплуатации

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Initial Checkout Procedure
The following procedure will verify that the MegaPulse 1.2x50-16PF PV tester is working
correctly. We recommend that this procedure be conducted periodically to ensure proper
operation of the tester. A measuring instrument to monitor the output waveform is needed to
conduct this procedure. Always ensure that the measuring instrument (usually an oscilloscope
with a high-voltage probe) is rated for the voltage involved, and that the frequency response of
the instrument and probe are capable of measuring the output waveform of the MegaPulse
1.2x50-16PF PV tester. A measuring instrument or probe with a low frequency response will
result in erroneous readings that could be mis-read.
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. Connect the tester to a proper source of supply using the included 18 AWG power supply
cord.
2. Connect the red and black test leads to the EUT.
3. Connect the ends of the test leads to an appropriate measuring instrument (typically an
oscilloscope with a high-voltage probe).
NOTE: The output of the MegaPulse is a high-energy fast-rise (>10kV/uS) waveform.
Depending on the measurement setup, it is possible to see very large common-mode noise
which can be mis-interpreted as high-frequency noise on the front edge of the impulse
waveform. Figure 5 shows a test setup to measure common-mode noise. The high-voltage
oscilloscope probe, and the probe ground are both connected to one side of the MegaPulse
output. In theory, the result should be that 0 volts is measured on the oscilloscope. In
practice, because of the high-impedance of the high-voltage oscilloscope probe, the
oscilloscope will measure a substantial high-frequency transient as shown in Figure 6.
Before making measurements of the actual impulse output waveform, be sure to perform
some measurements as shown in figure 5 and take steps to minimize the measured noise as
much as possible. Some possible remedies to reduce common-mode noise are as follows:
a) Use a suitable oscilloscope and high-voltage probe.
b) Use a battery-powered oscilloscope.
c) Isolate the oscilloscope from ground.
d) Adjust the scope to limit the measurement bandwidth.
e) Perform a two-channel differential-mode measurement, where the common-mode noise
is subtracted from the impulse waveform.
If this common-mode noise is not eliminated in the test setup, the common-mode noise will
also be measured when the high-voltage impulse output is measured. The result will look
like the waveform shown in Figure 7, where the high-voltage common-mode noise is
essentially added to the differential (impulse) voltage.