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Variable transformers

Electric Test Solutions

Variable transformers are used to regulate alternating voltages or currents under load between zero and the nominal value. They are suitable for the power supply to resistive, inductive or capacitive equipment.

Ruhstrat® variable transformers are developed, manufactured and tested in accordance with relevant EC directives, European standards and VDE regulations, in particular DIN EN 61558-2-14 and VDE 0552.

In a column-type regulating transformer the voltage adjustment is achieved through amplitude adjustment. Column-type regulating transformers do not change the curve forms between the input and output voltage and no harmonics or surges are generated.

Technical specifications

  • Voltage up to 1,000 V
  • Frequency range 800 Hz
  • Degree of protection up to IP 54
  • Variable toroidal and column-type regulating transformers
  • Single-phase or three-phase variable transformers
  • Version as an autotransformer or with a galvanically separated winding
  • According to IEC EN 61558-2-14 and VDE 0552
  • Designed for heavy-duty operation
  • Less voltage drop due to compensating windings
  • Hard silver-plating of the most important contact points – for constantly low transition resistance


  • High-voltage test facilities
  • Industry (electroplating, glass, etc.)
  • Control of industrial furnaces

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