What Is Induction Heating? & How Does It Work?

  Induction heating is the use of electromagnetic induction to make the internal current of the heated material, relying on the energy of these eddies to achieve the purpose of heating. The basic components of the induction heating system include an induction coil, AC power supply, and workpiece. Coils can be made into different shapes depending on the heating object. The coil is connected to the power supply, which provides an alternating current to the coil. The alternating current flowing through the coil creates an alternating magnetic field passing through the workpiece. The magnetic field causes the workpiece to produce eddy currents to heat the workpiece.

Simple Induction Heater

  The fundamentals of induction heating: Electromagnetic induction was first discovered by Michael Faraday and has been used in manufacturing since the 1920s.During World War II, technology was rapidly developed to meet urgent wartime requirements for fast, reliable processes to strengthen metal engine parts. More recently, a focus on lean manufacturing techniques and an emphasis on improved quality control have led to the rediscovery of induction technology, with the development of precision control, all-solid-state induction power sources.

Michael Faraday

  What makes this heating method so unique? In the most common heating method, a torch or open flame is applied directly to the metal part. But with induction heating, the heat is actually part of the “induction” that itself circulates within the current range.

Induction heating depends on the unique characteristics of radio frequency (RF) energy – that is, part of the lower infrared and microwave energy of the electromagnetic spectrum. Because heat is transferred to the product by electromagnetic waves, the parts do not come into direct contact with any flame, the inductor itself is not heated (see figure below), and there is no product contamination. If set up correctly, this process can become very repetitive and controllable.

These eddy currents produce accurate and local heat to the metal without any direct contact with the inductor. The heating occurs in two magnetic and non-magnetic parts and is often referred to as the “Joule effect”, referring to the Joule first Law – a scientific formula expressing the relationship between heat generated by the transfer of an electric current through a conductor.

Induction heating schematic

  When the magnetic component passes through the inductor, internal friction is generated – second, additional heat is generated within the hysteresis magnetic component. The magnetic material naturally provides resistance to the rapidly changing magnetic field into the inductor. This resistance produces internal friction, which produces heat.

  In heating the material, there is, therefore, no contact between the inductor and the component, and no combustion gas. The material is heated and can be located in a setting isolated from the power supply; Immerse in a liquid, cover with an isolating substance, in a gaseous environment, or even in a vacuum.

Important factors to consider

  The efficiency of an induction heating system for a particular application depends on several factors: the characteristics of the parts themselves, the design of the inductor, the capacity of the power supply, and the amount required for the temperature-varying application.