Induction Furnace Power Supply Unit

Induction Furnace Power Supply

Induction furnaces are vital in any metalworking and are used for various purposes, such as heat treatment. But the main thing lies in the power supply unit of the furnace, which does the main tasks that lead to heat generating and an easy melting process.

Mainly used for intense heat generation, the induced furnace power supply has some advantages, but you won’t get them until you know the working principle of the power supply.

So, in this article, we will discuss them all to ensure you know the supply unit more.

Induction Furnace Power Supply & Its Purpose

The induction furnace is a device used to produce heat for metal melting or smelting. It has a crucible that holds the metal with a coil installed around it. The coil connects to the electrical power supply, which gives

The power supply comes with a wide frequency scope and a capacity control option; The power supply has a protection form over or under voltage.

Induction furnace power supply power supply was developed to support and assure optimum performance. The power supply of the induction furnace takes a 3-phase frequency into a single-phase power at the desired frequency.

The purpose of the power supply is to minimize energy consumption while having more efficient melting work.

Understanding the Construction of Induction Furnace Power Supply

Before understanding the construction of the induction furnace power supply, you should know the internal components and their roles well. For the desired output, the power supply has several main parts. It works together to get the desired power.

Coils and inductors are the core of the power supply unit. Their function is to form a winding of the high-frequency transformer. The winding is both primary and secondary. The primary coil gets the electrical energy, and the secondary works to transfer it to the chamber, which creates a powerful electromagnetic field. The primary coil gets energy from an external source.

The following important components are capacitors and their banks, which regulate the power supply. The banks store energy to release it in controlled bursts later while ensuring a stable output. When the energy is controlled carefully, it helps the power supply to deliver the required power according to the demand of the induction furnace.

Lastly, the rectifiers and inverters convert AC into the DC, or in some situations, DC into AC.

Mainly it is a rectifier that converts AC into DC power that is then supplied to the inverter. (this process ensures an efficient utilization of power). At the same time, the inverter is the one that converts the DC into AC which is best for driving the primary coil. (to efficiently convert the power between two forms, it is efficient to use inverters and rectifiers.).

Below is a circuit diagram of the power supply used in induction heating:

Power Supply Circuit for Induction heating and melting application
Power Supply Circuit for Induction heating and melting application

How Does Induction Furnace Power Supply Work?

Now that you know the fundamental comprehension of constructing an induction furnace power supply unit, let’s explore its working principles. The process can be simplified into a few key steps:

Input Supply: The power supply source is a static line frequency to medium/high-frequency converter. Typically, industrial power is available at line frequency, 3-phase. However, induction furnaces require high-frequency power to be fed to the induction coil for heating/melting applications.

Rectification – The 3-phase incoming supply is fed to a 3-phase full wave rectifier. This rectifier converts the AC supply into a DC supply. During operation, the converter thyristors remain fired at a maximum firing angle, ensuring a continuous DC supply to the inverter while the power is on. The DC choke filters the rectified supply to smoothen the DC supply further.

Filtering – A L/C filter filters out the high-frequency ripples and ensures a smooth DC supply. This filtering prevents unwanted disturbances from going back to the mains.

Inversion (DC to AC Conversion) – The filtered DC supply is then fed to a transistorized inverter, which converts it back to an AC supply at the desired high frequency.

Output to Induction Furnace – That power is delivered to the primary coil (through the coil and inductor setup). That leads to the magnetic field that induces current in metal charge leading to metal heating and melting. The inverter can regulate the power delivered to the induction coil. The switching frequency of the inverter is varied to change the output power. The switching frequency is automatically adjusted to the required value depending on the power the operator demands.

Benefits of Induction Furnace Power Supply

An induction furnace power supply unit offers several significant advantages in industrial applications. Let’s explore some of these benefits:

High Efficiency

Induction furnace power supply units are known for their high energy efficiency. The power supplies in induction furnaces feature strong silicon-controlled rectifiers that generate the necessary frequency and amperage for batch melting.

“These power units incorporate heavy-duty silicon-controlled rectifiers that are able to generate both the frequency and the amperage needed for batch melting and are able to achieve electrical efficiency levels exceeding 97%, a substantial improvement over the 85% efficiency typical of induction power supplies of the 1970s. The new designs allow maximum utilization of furnace power throughout the melting cycle with good control of stirring.”

Precise Control

The power supply unit allows for precise control of the heating process. By adjusting the frequency, voltage, and current supplied to the induction furnace, operators can achieve accurate temperature control and maintain the desired metallurgical properties of the melted metal.

Faster Melting and Heat Treatment

Induction furnaces with efficient power supply units offer rapid melting and heat treatment capabilities. The intense electromagnetic field generated by the power supply facilitates quick heating, reducing processing time compared to traditional methods (gas furnaces).

Environmentally Friendly

Furnaces that use combustion to produce heat produce by-products that are not clean and impact the environment negatively.

An induction furnace uses an electric power supply and requires no combustion. It is a clean method because it uses induction heating that produces heat to melt the material.


The induction furnace power supply unit is a critical component that drives the efficient operation of induction furnaces. By harnessing the power of electromagnetic induction, these units enable the melting and heat treatment of various metals. Understanding the power supply unit’s construction, working principles, and benefits is essential for optimizing its performance and ensuring productive and sustainable metalworking processes.

Whether it’s for melting steel, aluminum, or other metals, the induction furnace power supply unit plays a crucial role in shaping the future of modern metallurgy


Induction Furnace – An Overview – International Journal of Engineering and Technology Vol.3