What is the Working Principle of Induction Heater

If you are working in a Steel Factory then Induction Heater will be a common heating processes for melting, bending of metal. Normally the processes we use for heating any object is directly make a contact with hot objects or fire, or by the flame of fire.

But for Induction heating method we do not make any contact with object and fire or flame. Now just have a close look of the picture below and you will find the basic working principle of an induction heater.

Working Principle of Induction Heater
Working Principle of Induction Heater

In this photo there are some coil which uses to make by copper and its called induction coil. If you already know how a transformer works then understanding of induction heater will be easier for you.

Because induction heater and power transformer working principle is little bit similar to each others. There is primary and secondary coil in power transformer. When we apply the AC current through primary coil then it creates a variable magnetic field. Now this magnetic field creates an effect on secondary coil.

And this variable magnetic field from primary coil creates a variable current on secondary coil.

Read: Transformer Working Principle, Construction and Types

Let’s consider this copper coil is a primary coil and the object we are going to heated is a secondary side with short circuit connection. When the current goes through the secondary side then this current will called eddy current. This secondary resistance will prevent it and for this reason the heat will be generated and the object will be heated.

And this is the main reason of induction heating system. But there is some limitation. Because the object we are heating will not maintain the constant heating process from its outer side and inner side. The outer side of heating object will become more heated than inner side.

Now the main reason behind this principle of heating is call the skin effect. For the skin effect the amount of current generates in secondary coil will flow through the outer side of heating object then the inner side.

Because electrons used to move an object from its outer surface to little bit inner surface but not in the inner center point of object. If we go to the center of the object then current density will be decreased.

Also, due to hysteresis the object becomes slightly heated. The changing or variation magnetic field wants to allocate the objects molecule along the direction of the field. But when the direction of the magnetic field changes then some molecules do not want to change their current orientation to a new state.

For this reason each times some amount of the magnet energy holds in the object. To keep hold this magnetic energy for the primary is a loss and it’s called hysteresis loss. Now this energy is converted into heat.

Now come to the most advantage of this heating method and it is the no contact with the object. For this reason during heating process the abject is safe from any pressure and remains intact. You will find several applications of induction heating from your home to industry.

Read: What is Inside a Programmable Logic Controller (PLC)

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