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How Does Induction Heating Work

Induction heating is an application that based on the magnetic induction principle. It uses the eddy current to heat the part placed in the alternating magnetic field. (The part is metal or nonmetal conductor like graphite.)

In the induction coil (inductor/coil), the high-frequency alternating current will first generate an alternating electromagnetic field. Then, the magnetic line will form a loop when passing through the metal part/nonmetal conductors. Following that, an induced current will be generated in the cross-section of the part to be heated ( we normally call this type of current as eddy current). Finally, the eddy current of the part to be heated will heat up fast under the action of the resistance of the part, so as to eventually realize the purpose of heating the parts.

A complete set of induction heating machine includes the high-frequency heating generator (power supply), transformer, and coil:


The generator for high-frequency induction heating is responsible for converting the power supply ( such as 3P380V/50Hz or 3P220V/60Hz, or single-phase power supply) into the form of high-frequency, high-voltage, and low-current output.

The transformer of the metal heating machine is responsible for converting the high frequency, high voltage, and low current provided by the high-frequency heating generator into the output mode of high frequency, low voltage, and large current. Also, the transformer needs to isolate or adapt the output according to the different heating applications.

The coil is responsible for forming a strong high-frequency magnetic field around it after passing high-frequency, low-voltage, and large current. Generally, the larger the current, the higher the magnetic field strength. The coil needs to be designed according to the shape of the heated part and the heating position. Thus, it is not limited to the spiral tube or flat form.

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