Resonant Test Systems is applied for the generation of a continuously variable alternating ( AC) voltage of a fixed frequency ( mainly 50 or 60 Hz) for high-voltage ( HV) routine, type and development testing of capacitive test objects. Capacitive test objects are cables, capacitors, but also large rotating machines, instrument and power transformers ( for applied voltage tests) . Resonant test systems enable not only HVAC tests at 50/ 60 Hz, but also at higher or lower frequency ( 10-300 HZ) and dynamic tests with fast voltage changes ( e. g. for capacitors) . Because of their precise sine-wave, resonant test systems are very well suited for the combinations of HVAC withstand tests with partial discharge ( PD) measurement. Frequency 10-300HZ Up to 1200KV Up to 20MVA