Eddy currents

INTRODUCTION

Definition: Eddy current is an induced current in a conducting coil that is generated as a result of the change in magnetic flux. It is named Eddy because of its eddy-like appearance. As per Faraday’s laws of induction, Eddy Currents flow in closed loops, and in planes the Eddy Currents are perpendicular to the magnetic field. 

If we take an electromagnet and attach a battery to it, it will produce a current in the magnetic field. It will induce current on the magnetic plate too. Thus induced current will be in the form of eddies in the plate. The currents are called Eddy Currents because they have whirlpool-like structures or are formed in the pattern of eddies in the water. 

Eddy current is found in every solid. Indeed, it is one of the fundamental properties of all solid conducting bodies. When a conductor has a change in its magnetic flux, the free electrons present in the conductor get a sudden magnetic force, and due to the effect of this sudden magnetic force, these free electrons start moving. They move by forming small eddies, and the electric current generated because of this motion of the electrons in the form of eddies is known as Eddy Currents. Eddy Currents are also known as Foucault’s currents. 

Faraday’s Law of Induction

Michael Faraday was an English physicist who discovered magnetic induction in 1830. He gave a law that states how an electric current generates a magnetic field and how the change in the magnetic field brings a magnetic current and generates an electric current in the conductor. Before understanding Faraday’s law of induction, knowledge regarding magnetic fields is necessary. When we compare magnetic fields with electric fields, we find that the magnetic field is a more complex one. The magnetic poles are always in pairs. The magnets have two poles, the north pole and the south pole. In accordance with Faraday’s law, Eddy Currents may be defined as the loops of electrical currents within conductors caused by a field in the conductor.

Uses of Eddy Currents

Eddy Currents are very useful in our lives. Even in our daily routine, we rarely use the term “eddy current” but make the utilisation of Eddy Currents on a daily basis. Here are some common uses of Eddy Currents:

• Eddy Currents are used to extract metals from their ore by making use of their heating properties.
• Eddy Currents are also used in medical concerns such as deep heat treatment of patients, and also these are used to heat the localised tissues in the human body. 
• Instruments like speedometers and energy metres also use Eddy Currents. 
• Eddy Currents are used in magnetic breaks too.

Electromotive Force

The electromotive force, also written as EMF, is an electrical action generated in a conductor. It is produced by a non-electrical source. A transducer that converts one form of energy to another provides electromotive force by converting other forms of energy to electrical energy. An electric generator or a battery are transducers that produce EMF or electromotive force. 

The generator or battery converts chemical energy into electrical energy. They have two terminals. One of the terminals is positively charged, and another terminal is negatively charged as they start working on the electric charge being transferred within themselves. Thus, through this process, the energy gained per unit electric charge is known as electromotive force. 

In other words, the electromotive formula may be defined as the electric potential produced by either electrochemical cells or by the change in the magnetic field. In the International Metric System, the electromotive force is abbreviated as E. However, it is also known as EMF. The common measuring unit of EMF is Volts.

Calculation of Electromotive Force

We can calculate EMF or electromotive force by using the flowing formula:

                          E = W / Q

Here, E stands for electromotive force, W stands for work done, and Q stands for the charge.

For the purpose of the production of electromotive force, it is necessary to find the difference between the potential of both the poles where one pole is positive and another pole is negative. If we talk about the electromotive circuit, it can be open and closed. 

Conclusion 

Thus, we can say that Eddy Currents are the currents that are generated in conductors as swirling eddies. It is produced in a conductor when there is a change in the magnetic flux linked to it. It was discovered by a physicist Foucault.

There are many important applications of Eddy Currents in our daily life. Since Eddy Currents have heating properties, they can be utilised in multiple ways.

The strong Eddy Currents, which produce very high heat, are used to extract metals from their ores. As these currents are flown through the ores of metals, the metals meltdown from their ores. Thus, the process of heating the metals from their ores by the induction of strong Eddy Currents is known as an induction furnace. Except for this, Eddy Currents are useful in many other ways too. However, one amazing fact we notice in the case of Eddy Currents is that we do not get shocked due to the Eddy Currents though it produces strong heat. It is because we get shocked due to the difference between the conductor and the ground, and there is a very small difference in eddy current-voltage shock, so we do not get shocked. 

The electromotive force, also known as EMF, is produced in a conductor by transducers like electric generators and batteries. These transducers have the task of converting the chemical energy to the electrical form of energy. It works on the electric charge which is transferred into them, and by this process, the gain per unit electric charge is known as electromotive force.