Discover Induction Heating:
The Future of Efficient Industrial Heating
How Induction Heating Works
Is a highly efficient, non-contact method of heating conductive materials, such as metals, by generating electric currents within them using electromagnetic fields produced by an induction coil. This process, driven by alternating current (AC) from power supplies (inverters), offers precise temperature control, rapid heating cycles, and energy savings, making it ideal for applications ranging from brazing and annealing to forging and melting. Unlike traditional methods, induction heating minimizes heat loss, enhances safety by reducing open flames, and supports sustainable manufacturing, which is why industries worldwide rely on this technology to boost productivity and meet stringent quality standards
Key Principles: Electromagnetic Induction
Induction heating relies on three core physical phenomena:
electromagnetic induction, skin effect, and heat transfer
Electromagnetic induction
Electromagnetic induction, discovered by Michael Faraday, is the foundation of induction heating. When an alternating current (AC) flows through an induction coil, it generates a time-varying magnetic field. This field induces eddy currents in a conductive workpiece placed within or near the coil. The eddy currents produce heat due to the material’s electrical resistance, a process governed by Joule’s law (P = I²R, where P is power, I is current, and R is resistance).
Skin Effect
The skin effect refers to the tendency of alternating current to concentrate near the surface of a conductor. In induction heating, this results in higher current density—and thus more intense heating—at the workpiece’s surface. The depth of penetration (skin depth) is inversely proportional to the frequency of the AC and the material’s magnetic permeability and resistivity. For example:
- High-frequency systems (50–400 kHz): Shallow skin depth, ideal for heating small components.
- Low-frequency systems (1–25 kHz): Deeper penetration, suitable for through-heating applications like forging bigger components.
Heat Transfer
Heat generated by eddy currents is transferred within the workpiece primarily through conduction. In some cases, magnetic materials (e.g., steel below the Curie point) also experience hysteresis losses, contributing additional heat. The efficiency of heat transfer depends on the workpiece’s thermal conductivity, geometry, and the induction system’s design. Precise control of power and frequency ensures uniform heating or targeted temperature profiles as required by the application.
Main Components, Induction Power Supply and Coil
The main components of an induction heating unit consists of an Induction Power supply or inverter, capacitor bank and induction heating coil
Induction Power Supply
Converts mains electricity to high-frequency AC, typically in the range of 1 kHz to 1 MHz. Power ratings vary from 1 kW for small-scale applications to several megawatts for large industrial processes, allowing flexibility based on heating requirements. Find out more on our Power Supply page
Capacitor Bank
Either integrated into the power supply or installed remotely, the capacitor bank, also known as the LC circuit, connects to the induction coil. It is tuned to match the resonant frequency of the coil to the power supply’s output frequency, optimizing energy transfer and system efficiency.
Induction Heating Coil
A copper induction heating coil, custom-designed to match the workpiece’s geometry, carries alternating current (AC) to generate the magnetic field. Coils are typically water-cooled to prevent overheating, ensuring durability during high-power operation. Air-cooled coils are available for lower power applications (e.g., <10 kW) or specific processes requiring minimal cooling. At KI Solutions we recommend water cooling when performance and continuous heating is required.