General information:

VLF Test Sets from 30kV - 90kV with Sine Wave Output

VLF means 'Very Low Frequency' is used in AC hipot test for power cables, transformers, switchgear and other electrical apparatus.

A VLF hipot is just an AC output tester but with an output frequency of 0.1 Hz or lower rather than 50/60Hz. Although the frequency is very low, it is still an alternating current with polarity reversals every half cycle. At 0.1 Hz output, rather than 60Hz, it takes 600 times less current and power to apply an AC voltage to a capacitive load, like a long cable.

VLF (Very Low Frequency) Testers are suitable for testing power cables, transformers, switchgear, rotating machinery and other electrical apparatus.

Features:

√  Adapts microprocessor controlled, can realize voltage set-up/down, measuring and protecting automatically. Manual intervention is allowable even during the auto voltage boosting.

√   Portable, easy to move.

√   Large LCD can display waveform clearly, and test report can be printed by built-in printer.

√   The data of current, voltage, and waveform can be sampled at HV side.

√   Over voltage protection: When the output is beyond the limitation, the control unit will shut itself down within 20ms.

√   Over current protection: high & low voltage double protection, the precision value of power off protection can be setting at HV side. When the current of LV side is exceeded rated, the control unit will shut itself down within 20ms.

√   HV output protection resistor is built in the booster, not need to connect outside resistor.

√   Adapting high & low voltage closed loop negative feedback control circuit, there is no capacitive rise effect during the output.


Specifications:

√   Accuracy: 3%                                  

√   Voltage +/- peak value error: ≤3%

√   Voltage waveform distortion: ≤5%

√   Working temperature: -10ºC+40ºC
√   Working humidity: ≤85%RH