Megger ADX15, User Manual

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Surge Testing Notes and Recommendations
The following notes are provided for additional insight into specific Surge testing issues and situations.
Surge Testing with Rotor Removed (typically shop testing)
„ Enable L-L EAR and set tolerance to 2% (form wound asset).
„ Enable LL-EAR and set tolerance to 3% (random wound asset).
„ Enable P-P EAR and set tolerance to 2–5%.
Surge Testing with Rotor Installed (typically field testing)
„ Enable P-P EAR and set tolerance to 10%.
„ Disable L-L EAR when testing in the field.
NOTE: L-L EAR can be used in cases where you know that the specific asset has minimal rotor influence
or standard offset by design.
False Pulse-to-Pulse EAR Failures
In some assets, the waveform will slowly migrate to the left as the voltage is increased. This slow draw to the left
is caused by rotor influence. If the voltage is increased at too fast a rate, the movement can cause the P-P EAR to
generate smooth but large changes that could exceed the P-PEAR limit threshold leading to a potential failure. To
eliminate this nuisance trip, set the Voltage Ramp Rate to a lower value in the active test configuration.
Removing Ancillary Components
When performing electrical testing on an asset (applies to all test types), all ancillary electrical components should be
removed from the circuit under test. These devices could lead to artificially lower insulation readings, and shifts and
attenuation of the surge waveforms. Such devices include but are not limited to, power factor correction capacitors,
lightning arrestors, surge capacitors, auxiliary devices being powered from the motor incoming power leads, and more.
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Surge Testing Notes and Recommendations