FSHV offers three different types of AC voltage test systems, the conventional type is AC test transformer design, mainly for testing objects of medium & low capacitance products, particularly for tests requiring stable voltage even if the load changes under voltage (corona, wet & pollution tests) or when the load is inductive (like inductive voltage transformers). Another is AC resonant test systems, according to series resonance circuit XL=XC (2πfL=1/2πfC), by setting F frequency of power supply or L inductance of reactor, generate a pure sinusoidal waveform of the test voltage, and the required input power is only 1/Q. Variable frequency type operates in a frequency range from 20Hz to 300Hz, ideal for field commissioning test of power cables and GIS/GIL. Variable inductance type outputs continuous AC voltage of power frequency (50/60Hz), mainly for factory testing of high and ultra-high voltage cables, power transformers, GIS, etc.