Compliance West MegaPulse 1.2x50-12.3PF-1, Instruction Manual

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Pressing the POLARITY switch on the front panel can change the polarity of the output
waveform. The polarity is Normal when the
NOR indicator is lit. In this case, the high voltage
will appear on the OUTPUT as a positive pulse relative to the RETURN jack. When the
polarity switch is in the Reverse position ( REV indicator is lit), the high voltage will appear on
the OUTPUT as a negative pulse relative to the RETURN jack. The polarity switch only
operates when the CHARGE LED is lit, i.e. the output is not charged.
Note that the voltage meter may indicate that some residual voltage is present on the main
storage capacitor, even when the tester is first turned ON. This is due to inherent charging of the
internal capacitors. Pressing the
TRIGGER switch will discharge the capacitors (be sure not to
touch the output and return leads when pressing the trigger switch).
Note that the peak amplitude of the measured output waveform is proportional to the voltage that
is read on the front panel of the MegaPulse, but it will always be somewhat lower. This is
because the meter on the MegaPulse is measuring the voltage on the main impulse storage
capacitor. This voltage will intentionally dissipate to some extent before reaching the output
leads. Therefore, it is important to measure the peak amplitude of the output waveform, and
adjust the output of the MegaPulse accordingly.
Determination of Passing and Failing results can prove difficult. To obtain the most accurate
results, it is generally necessary to perform multiple impulse tests on a few different test samples
(that have adequate insulation to pass the impulse test). Take note of the impulse waveshape,
amplitude, and duration. Also note how much variance there is in the waveshape from test to
test. Also (if possible), perform impulse testing on some test samples that are known to have
inadequate (or damaged) insulation. Take note of the impulse waveshape, amplitude, and
duration, when an insulation breakdown occurs.