The isolation transformer commonly known as safety transformers, refers to the transformer of the input winding and output winding with the electrical isolation device. Which is used to carry out the electrical isolation to two or more coupling circuits. The isolation transformer is generally used for machine repair and maintenance, playing the role in protecting, protecting thunderstruck, filtering, so as to avoid accidental contact with charged body simultaneously. The transformer can isolate their respective current of original secondary-side winding coil. The isolation transformer is used in the power industry in European countries in early time, widely used in the electronics industry or industrial and mining enterprises, also used for the control power of general circuit in the machine tools & mechanical equipment, the power of safety lighting and indicator lights.

Transformers are widely used in a variety of electronic products, its main functions are: voltage conversion; impedance transformation; isolation; regulated voltage (magnetic saturation transformer) and so on. There are two common reasons for the transformer damage: primary overvoltage and secondary short-circuit. Both of these faults cause the transformer's "copper loss" (heat dissipation of the current through the coil) and "iron loss" (loss induced by "eddy current") increasing rapidly in a short time and result in the coil temperature rising ; If these faults can’t be handled in a timely manner, the coil insulation performance will be reduced, and even burn the transformer. If the above-mentioned transformer failure occurred and the transformer was not timely cut off, thus, some part of associated components in the circuit will correspondingly cause the overload or overwork. In severe situation, part of components will lead to failure due to overheating, resulting in the local circuit damaged.