AC resonant test system with variable inductance, metal tank type

The WR AC resonant test systems with variable inductance are used for factory testing of medium and high voltage cables, high voltage capacitors, generators, and motors. They use the resonance between the capacitive test object and the
inductive HV reactor of the test system to generate a continuous sinusoidal high voltage. The natural resonance frequency of the test circuit is matched to the feed-in mains frequency 50/60 Hz by setting the variable inductance of the HV reactor.
If the HV reactor and test object are designed to form a series resonant circuit, the result will be an ideal sinusoidal testing voltage. The oil-cooled HV reactor is installed in a closed steel tank. The high voltage is fed outward through the steel tank via a HV bushing. The reactor can be fitted with additional voltage taps (bushings) to achieve largest testable capacitances of test objects at lower test voltages.


  • For routine testing of medium and high voltage cables up to 400 kV in accordance with IEC 60502 und IEC 60840
  • For routine testing of high voltage capacitors up to 60 kV in accordance with IEC 60871
  • For routine and inspection testing of generators and motors up to 60 kV in accordance with IEC 60034


  • Low level of partial discharge < 2 pC
  • Higher duty cycle thanks to excellent cooling properties
  • Low power demand due to high quality factor
  • Ideal sinusoidal test voltage for series resonance systems
  • Low noise level thanks to special mechanical design
  • Low maintenance operation over the entire service life of the test system

Technical parameters/system types


Tests systems for series resonance


Tests systems for parallel and series resonance