Very Low Frequency AC Testers 0.10 Hz. – 0.01 Hz. – 0.01 Hz. sinusoidal

vlf series - HVI

AC Withstand & Diagnostic Test High uF Loads

VLF Series: The Original HVI Patented VLF Product Line - Since 1998


VLF Technology – Why? The lower the frequency of an AC voltage applied to a capacitive load, like a power cable or generator, the lower the AC charging current required. To field test high uF loads with AC voltage requires the use of VLF AC technology instead of conventional 50/60 Hz. supplies.  Amps = 2µƒCV. 60 Hz:0.1 Hz. = 600:1 = 600x less current.


VLF Series: The original line of HVI patented VLF products, rated from 30 kVac – 200 kVac, was developed and released in 1998 and quickly revolutionized cable testing worldwide. The HVI VLF line was the first portable and affordable 0.1 Hz. design and was constructed like conventional hipots the world was familiar with: oil filled HV tanks and analog designed controls. Economical, easy to use, rugged, reliable, and portable, this design quickly captured the bulk of the world market with thousands sold to over 100 countries. Many models are available to test medium and high voltage power cables up to 200 kVac. The VLF Series is manual in control and operation making it easy to use and service but is limited in its data logging capabilities.

VLF E Series Solid State Automatic Design Featuring the HVI E-Link Software


VLF-E Series: The E Series line of VLF products is the latest generation of solid state power supply designed VLF testers. Ratings available from 34 kVac – 65 kVac, and offer complete programmable and automatic operation, strong Xbee wireless communications and extensive data logging, and the leading user interface software package available, the  E- Link Software.


E-Link VLF & TD Operating Software


E-Link Software: The most recently create and most comprehensive, yet easy to setup and use,  software package for the control, monitoring, data collecting, and data reporting for cable testing performed using the VLF E Series of Very Low Frequency AC generators and the TD-65E Tan Delta measurement instrument. This package from HVI makes all the difference in the field, when reliable, dependable, and easy to use operation, data logging and reporting are needed. The E-Link is far more powerful in its abilities, reliable, and flexible in use than all others.

0 - 200 kVac VLF. Since 2004. With PD & TD Diagnostics


Since 2004, HVI has delivered its 200 kVac VLF model, in its two piece configuration and in several van, truck, and trailer design configurations, with generators and Tan Delta & Partial Discharge Diagnostic accessories.

A Few More Photos of the VLF-200CMF in Action.


Various Van & Truck Mounting Options