Automatic Voltage Stabilizer
are used for high power applications where a stable voltage is required, independent of line voltage variations and changes of load.

Automatic Voltage Stabilizer guarantee a high long- term stability of the output voltage stability of the output voltage. Additional available special equipment offers a balanced, separated and earth free supply system in star – connection with fully loadable neutral conductor.

and after – if fitted with optional available special equipment- a balanced separated, and earthfree supply system in star- connection with full loadable neutral conductor.

This separated system can be connected and used for every safety system, standardized and as TN- or TT- or IT-system and their variants.

If required, even input and output perturbations can be suppressed in both directions, with a directions with a perturbation attennation transformer, designed even as matching transformer and neutral magnetic coupler.

They are suitable for supplying resistive, inductive, or capacitive load, neither radio interference nor additional harmonics occur within the permissible operation range.

Automatic Voltage Stabilizer operate on a closed loop control. The output voltage is measured and compared with a high-stable reference in an electronic control unit. Whenever the output voltage deviates from the reference for more than 1% (standard), the servo drive is switched on until the output voltage has again reached the nominal value. This results in a booster voltage, to be added to or taken away from the line voltage, corresponding to the deviation.

Automatic Voltage Stabilizer consist of electrically and mechanically simple components. Painstaking material selection and careful manufacturing assure reliability, high effeciency and a long service life.

Our Automatic Voltage Stabilizer operate sometimes under extremely local and climatic conditions exact and reliable all over the world, they are used for supplying of
  • laboratories and test facilities
  • industrial electric heaters
  • data processing systems, especially in connection with our interference suppression transformers
  • radio transmission and receiving systems
  • radar systems
  • air conditioning systems
  • household appliances
  • accumulator charging equipment
  • dc-supply networks
Automatic Voltage Stabilizer are available as build-in units or as ready for connection and factory-assembled appliances in single-phase or three-phase design, even with additional special equipment; suited for input and output voltages up to 1000V 50...60 cps and loadable up to 550 KVA depending on number of phases and standard operating range +/- 10%, +/- 15%, +/- 20% .

Special equipment

On request, Automatic Voltage Stabilizer can be equipped with additional features, e.g. with
  • Matching transformers for different input and output voltages
  • Neutral electromagnetic coupler for supply systems without neutral conductor, as autotransformer circuit or as transformer with separated windings
  • Perturbation attenuation transformer resp. interference or noise suppression transformer with special characteristic for attenuation of common mode and transient perturbations
  • Application- oriented control, monitoring and signalling equipment
  • Extended or asymmetrical adjusting ranges, e.g. up to +/- 30% or up to + 10/ -30% etc.
What Automatic Voltage Stabilizer can not do:

  • Automatic Voltage Stabilizer are not able to regenerate the voltage at the end of long supply lines with to low conductor cross- section and too high systems impedance
  • A reliable stabilization is only possible, when lines and systems are so dimensioned, that the voltage drop between feeding and consumer point reaches no more than 4% of the rated voltage (DIN EN 60038 ) even with inrush or increased input current, regulating or increased input current regulating with low mains voltage.

    But, a reliable operation under limit conditions has been realized in some facilities with an intermediate circuit of increased voltage, transformed at the feeding point up to the highest admissible level for the available line system, reduced and stabilized to the rated voltage at the consumer point.
  • Automatic Voltage stabilizer are not able to regenerate frequency fluctuations or sine- wave departures of instable supply systems. For standard appliances, the absolute minimum frequency lasts 48 cps. , deviations of current or voltage waveform are transmitted in both directions without significant attenuation. Versions for ozher low frequencies on request.
  • Automatic Voltage Stabilizer are not able to eliminate short- peaks, glitches, or voltage dips. Control range, speed of synchronous servo drive, and rated frequency determine the correction time:

    Rated frequency 50 60 cps
    Correction  time 3,8 3,2 s
    Adjustment range +/- 10 15 20 10 15 20 %
    Correction speed at
    single phase 230V
    12 18 24 14 21 28 V/s
    triple phase 400V 21 31 47 25 36 50 V/s

    The correction times, listed above, apply when the voltage changes suddenly and then remains. However, a considerably shorter correction time can be expected because the control process begins previous with a voltage deviation of 1% .

For detailed information, please see our publication "Automatic Voltage Stabilizer".