How exactly does induction heating work?

It helps to have a basic understanding of the principles of electricity. When an alternating electrical current is applied to the primary of a transformer, an alternating magnetic field is created. According to Faraday’s Law, if the secondary of the transformer is located within the magnetic field, an electric current will be induced.

In a basic induction heating setup, a solid-state RF power supply sends an AC current through an inductor (often a copper coil), and the part to be heated (the workpiece) is placed inside the inductor. The inductor serves as the transformer primary and the part to be heated becomes a short circuit secondary. When a metal part is placed within the inductor and enters the magnetic field, circulating eddy currents are induced within the part.

As shown in the second diagram, these eddy currents flow against the electrical resistivity of the metal, generating precise and localized heat without any direct contact between the part and the inductor. This heating occurs with both magnetic and non-magnetic parts and is often referred to as the "Joule effect", referring to Joule’s first law - a scientific formula expressing the relationship between heat produced by electrical current passed through a conductor.