Compliance West MegaPulse Capacitor A PF Series, Instruction Manual

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Section 1
An Introduction to Impulse Testing with the MegaPulse PF series tester
The impulse test is designed to simulate impulse surges which occur in everyday life due to nearby
lightning strikes, switching transients, and other high-frequency faults on the power distribution network.
Impulse testing is the fundamental method for empirical verification of the adequacy of insulation. Other
methods of ensuring adequate insulation (AC or DC Dielectric Withstand testing, measurement of over-
surface creep age, through-air clearance, or distance-through-insulation) are all extrapolated from the
results of impulse testing. The impulse test is performed to ensure that the insulation in question will be
able to function properly when subjected to similar impulse surges in the field.
Safety Precautions
The impulse withstand test can generate voltages in excess of 8000V peak at potentially lethal current
levels. Currents of as little as 5mA at 120 volts can cause death; the MegaPulse can deliver currents of
more than 296 Amps peak for very short time duration. The potential for serious injury or death exists
and personnel should be aware when they conduct this test.
Test Personnel
Personnel require special training to conduct the impulse test. They should understand electrical
fundamentals clearly, and be aware that high voltage is adept and creative at completing a path to ground.
Instructions should include a warning against any metal jewelry. Operators should not allow others in
the testing area, especially when tests are being conducted. Organization is to be stressed. The operator
should keep the area free of unused leads and equipment.
Testing Area
The area used for conducting the impulse test should be as remote as possible from normal production
line activities. Only personnel actually conducting the test should be allowed in the area, and it should be
taped or roped off to preclude casual entry by other employees. In addition, the area should be marked
"WARNING - HIGH VOLTAGE TESTING" or the equivalent to warn others of the nature of the testing
taking place.
The bench being used should be non-conductive, and any exposed metal parts should be tied together and
grounded. If a conductive surface must be used, it should be grounded. Because of sparking during an
impulse test failure, it is not safe to conduct impulse testing in combustible atmospheres.
It is imperative that a good ground be provided to the MegaPulse tester. Before connecting the
equipment, ensure that the building wiring provides a low-resistance ground. If the MegaPulse tester is
used on a high-resistance grounding circuit, dangerous high voltages may be present to the operator. In
addition, the power to the Testing Area should be provided with an easily reached shutoff switch which
can be actuated by personnel outside the Area if needed.