HV Equipment

AC Test Systems


HV TECHNOLOGIES, Inc. can provide AC test systems to be used for generation of high voltage in multiple application cases to meet your factory, laboratory, and on-site testing requirements. All transformers are of the highest quality, extremely reliable, and are guaranteed for a long service lifetime. The transformers are produced according to the customer's requirements, which means that any type of input voltage can be realized and special executions for higher and lower frequencies are possible.

ACS / PSZ - Cylinder Type Transformers 

ACS/PSZ Transformer


The ACS/PSZ AC Dielectric Test Systems are specifically designed for test applications which require a stable output voltage, even if the load may change during testing. For example for heavy corona, wet tests or pollution tests to name a few. These systems are also especially useful for when the load is inductive, such as inductive voltage transformers. Depending on our customer's specific needs, it's possible to stack several transformers - allowing us to reach very high voltages while also taking up very little valuable floor space. 


  • Flexible high voltage connection options
  • Compact dimensions perfect for minimum space requirements
  • Sophisticated protection features for optimal test object and personnel protection
  • Large range of applications
  • Low acoustic noise level (ca. 65 - 75 dBA)
  • Power compensation inductance guarantees linear voltage distribution for systems with 3 or more stacked transformers and reduces the power required on the primary (LV) side of the test system
  • Option to add air-cushion base frame

PSK - Tank Type Transformers


PSK Transformer


Conventional AC test transformers are especially designed for testing objects of medium capacitance in the factory, indoor or outdoor. These systems are particularly suited for tests requiring stable voltage even if the load changes under voltage (heavy corona, wet & pollution tests) or when the load is of inductive kind (inductive voltage transformers). The system duty cycle can be freely chosen and is insured by adding radiators or forced oil cooling to the transformers. These systems are also suited for continuous duty, long duration tests.


  • Specially designed bushings for indoor or outdoor use
  • Large range of applications
  • Low acoustic noise level (ca. 65 dBA)
  • Sophisticated protection features for optimal test object and personnel protection
  • Power compensation inductance reduces the power required on the primary (LV) side of the test system
  • Possibility to use an external oil expansion vessel or protection relay

AC Controls

Several different types of control units for the AC test systems can be offered and are designed for a number of test applications. These provide a safe and easy computer-aided operation of the ACS/PSZ cylinder type or PSK tank type AC test systems.

OT 248 AC Operating System

OT248 Control



  • 19" EMC hardened desktop housing 
  • Built-in safety interlocks
  • Switch-on, switch-off of the primary circuit breaker and the high voltage contactor
  • Manual variation of the output high voltage with two speed levels
  • Automatic raise of the output high voltage to a final value with a defined speed
  • Timer for switching off the high voltage automatically after a pre-set time period
  • Remote control compensation reactors of transformer test systems
  • Tuning and actual gap distance of the HV reactor
  • Over-voltage and over-current protection 


OT 257 AC Operating System

OT257 Control


This state-of-the-art industrial PC based and desk control system is specifically designed for the needs of high voltage testing. This control system is supplied with a Windows based control software package of which the development is based on the experience of three generations of AC test system controls. The system’s hardware has an EMC hardened design for safe use also in the most electrically noisy areas. 


  • Windows control software with easy and intuitive graphic user interface
  • Comfortable desk solution
  • Ability to control: output voltage, regulating voltage and current, rise time, testing time, gap distance, history, alarms, trips, grounding, safety, status visualization, data logging, data storage, status handling, automation, system diagram visualization and online help.
  • Full manual operation mode also possible
  • Free programmable Sequence mode optimized for automated production testing. A defined test sequence can be set up by the user easily, run by the software and the results are recorded. All test sequences can be recorded and saved for later use or repetition.
  • Full visualization of test system with measuring values, switch positions, earthing system, alarms, and warnings.
  • Integration of external measuring devices over ActiveX components and adaptation of its measuring values for remote operation and presetting of measuring devices.
  • OLE interface allows data access from other applications (e.g. Excel, Word, etc.) 
  • Automatic test report generation
  • Integrated reporting tool with user-definable layout, logo insertion, etc.

DMI 511 Digital Measuring Instrument


DMI 551


The Digital Measuring Instrument DMI 551 is an instrument for measurement of AC, DC, and impulse peak voltages by means of 3 independent channels. The instrument can also be used for firing a generator or a chopping sphere gap and to trigger an oscilloscope or any other measuring device. The instrument has also implemented a flash detector to store and display the last voltage measurement and its polarity before a breakdown or flashover occurred. Typical main applications of the unit include measurements of a voltage divider output or for automated product testing where the DMI 551 is integrated into a complete control and measuring platform. 


  • AC voltage measurement by capturing rms, peak and peak/√2 values
  • DC voltage measurement and evaluation of mean value and ripple factor
  • Impulse voltage measurement by capturing peak values of lightning or switching impulses
  • Impulse current measurement by acquiring the voltage across a current shunt
  • Triggering of generator and chopping gaps and any other measuring device
  • Flash detection of AC and DC flashovers. The generator can automatically be stopped from recharging
  • Remote control to operate the unit from a computer or a laptop
  • Plotter output for recording of AC and DC voltages on an external X-Y graph recorder
  • Easy to operate: Large LCD screen, case sensitive soft keys and special function keys reduce setup time and ensure intuitive and safe handling.
  • Manual re-evaluation tool for all impulse parameters.
  • Accurate and reliable: Well established hardware and extensively tested software allows meaningful and credible measurements.
  • Customized solution: Due to the flexibility of the DMI 551 many HV measuring applications can be covered with this single device. Cost effective investments are therefore guaranteed.


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