Light high voltage testing transformer for single-phase transformers in the series, operation box (set), voltage regulator (100KVA outside regulator with) adjustable output voltage of 0~200V or 0~400V to test the primary winding of the transformer, based on the principle of electromagnetic induction, high voltage in the secondary winding can be adjustable. High voltage bushing is equipped with high voltage silicon stack, threaded half-wave rectifier in high voltage circuit. When short circuit high voltage silicon stack short-time, high voltage AC output. Screw the short pole high voltage DC output.