3
Using the MegaPulse Impulse Tester
The impulse test involves high voltage and caution should be exercised when using the tester. The
RETURN
lead is referenced to building ground when properly connected. However, both the
OUTPUT
and
RETURN
leads must always be treated as Hazardous whenever the power switch of the MegaPulse is in the ON
position.
The MegaPulse PF tester is designed to bleed the high voltage away after the test has concluded. In order to
ensure that any voltage present in the equipment being tested has been completely bled away, the operator
should not unplug the equipment under test from the MegaPulse until the front panel meter reads a safe level
(40 volts or less is generally considered a safe level). Pressing the TRIGGER button before disconnecting
main power (or turning the equipment off) will ensure that the internal capacitors are discharged as much as
possible.
CAUTION
High voltage generated by the MegaPulse tester is exposed during this test. A risk of shock exists.
Exercise care when using the MegaPulse unit.
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.
Summary of Contents for MegaPulse 360
Page 1: ...Instruction Manual...
Page 2: ...i...
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Page 6: ...v...
