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Description
Sandi VLF High Voltage Dielectric Test Unit provide sinusoidal AC voltage but at 0.1Hz - 0.02 Hz, compared to the 50/60Hz output of conventional AC test sets. It is still an AC voltage with sinusoidal polarity reversals every half cycle. The Sandi VLF instrument is used to provide a simple go/no-go, or pass/fail withstand test. Also, Sandi VLF instruments can be used as the voltage source for performing off-line Partial Discharge testing.
Application
Sandi VLF testing is used for any application requiring AC testing of high capacitance loads. The major application is for testing solid dielectric cable, followed by testing large rotating machinery, and occasionally for testing large insulators, arrestors, and the like. Even if a utility doesn’t adopt Sandi VLF for widespread cable testing, one of the best reasons to use VLF is to check installation quality and accessories, like splices. Many failures are due to damage during installation, improper workmanship, and/or insulation damage caused by excessive voltage fault locating - thumping. At the very least, every newly installed or repaired cable should be Sandi VLF tested before re-energizing.
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Cable Insulation Instrument
