The principle of voltage boosting in test transformers is not mysterious; it is essentially the same as that of power transmission transformers in the electrical system—both rely on electromagnetic induction. However, it demands much higher requirements for voltage regulation range and output stability compared to ordinary transformers.

Electromagnetic induction voltage boosting

An AC power frequency is applied to the primary winding (low-voltage side) of the transformer, generating an alternating magnetic flux in the iron core. The secondary winding (high-voltage side) induces an electromotive force through electromagnetic induction. The ratio of output voltage to input voltage equals the ratio of secondary turns to primary turns. The HZG series has an input voltage of 200V or 400V. Through turn ratio design, it outputs high voltage of 50kV or 100kV (depending on the model) on the secondary side, adjustable continuously from zero to the rated value.

Voltage regulation is achieved through the accompanying control cabinet (console). The control cabinet is equipped with a built-in autotransformer. Rotating the voltage adjustment knob clockwise gradually increases the input voltage on the primary side from zero, while the output voltage on the high-voltage side rises linearly until reaching the set test voltage.

Advantages of CD-type iron cores

HZG employs a CD-type iron core wound with high-quality cold-rolled silicon steel, which, compared to traditional laminated iron cores, ensures a more uniform magnetic flux direction within the core through the CD-type winding process. This effectively reduces leakage flux and minimizes no-load current (HZG no-load current <4%), contributing to improved sine wave quality of the output voltage with reduced waveform distortion.

Epoxy vacuum cast coil

The coil windings are vacuum impregnated with epoxy resin, completely isolating the windings from the external environment. This results in significantly improved moisture resistance and mechanical strength compared to conventional wound coils, making them particularly suitable for field testing operations in outdoor and humid environments.