What is Eddy Current?

We know that whenever the magnetic flux passing through a coil changes then it will generate electromotive force and current. The same question arises when we want to know what happens when the magnetic flux is passed through a solid coil, will it also be able to induce emf and current? And the answer is yes. The current induced by the conducting body is known as the eddy current. What is eddy current is, basically eddy current is the current induced in any solid conducting body when the magnetic flux is passed through it. 

Eddy Current Definition

Eddy current is defined as the induced current in a conducting coil when a magnetic flux is allowed to flow through it or in other words, it is the induced current in a conducting body due to a change in magnetic flux. The eddy current definition can be explained as an important nature of a solid conducting body. 

Eddy Current Meaning

Now, let us have a look at the eddy current meaning and what is eddy current in detail. According to the eddy current definition we understood that it is the current generated or induced as a result of the change in magnetic flux. 

Now, what is eddy current meaning or what do you mean by eddy current?  whenever the conductor encounters the change in the magnetic flux, then the free electrons present in the conductor will experience a magnetic force. As a result of the effect of the magnetic force on the free electrons, these free electrons will move in the form of small loops or eddies, the electric current generated due to the motion of free electrons in the form of eddies is known as the eddy current. The generation of eddy current follows Faraday’s law of magnetic induction.

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The magnitude of induced eddy current can be calculated using Faraday’s law of magnetic induction. According to the second law of Faraday’s laws of magnetic induction, we know that induced emf is written as, rate of change of magnetic flux with respect to time will give rise to induced emf in the conductor, mathematically we get:

Emf = E = -\[\frac{dΦ}{dt}\]

Φ -The magnetic flux passed through the conductor

The negative sign is corresponding to the direction of the magnetic flux and is determined by the Lenz law.

Now, the current induced in a conductor whose resistance is R can be calculated by using ohm’s law, thus we get:

I= \[\frac{e}{R}\]

Where,

e-The emf induced in the good conductor as a result of the change in magnetic flux

R-The resistance of the conductor


Substituting the value of induced emf in the above equation we get,

 I = - \[\frac{\frac{dΦ}{dt}}{R}\] = -\[\frac{1}{R}\]\[\frac{dΦ}{dt}\]………(2)

Equation (2) is known as the expression for induced current. And the direction of induced current can be estimated by the Lenz law.

Uses of Eddy Current

To understand what is eddy current it is necessary to understand Faraday’s electromagnetic induction. There are many uses of the eddy current which is used in practical applications few are as mentioned below. 

  • In rapidly changing magnetic fields, due to the production of heavy emf, large eddy currents are induced. Eddy currents are capable of producing temperature as a result of this heavy temperature. Thus a coil-over a constituent metal is placed in a field of the highly oscillating magnetic field will produce a high-frequency ac. The temperature produced as a result of a heavy eddy current is enough to melt the metal. This is used to extract metals from ores.

  • Eddy currents are also used for the deep heat treatment of the human body. Eddy currents can also be used to heat the localized tissues in the human body.

  • Eddy currents are also used in the speedometers and energy meters.

  • Eddy currents are also used in magnetic breaks.

Did You Know

The eddy current testing nondestructive testing. And eddy current testing is an important part of our everyday life. Not everyone has heard of eddy current testing, but these methods touch all of our lives, perhaps even as a routine. This is because the eddy current techniques are used in a wide range of industries such as those industries where component failure could cause devastating damage and loss.

For instant, the eddy current testing is used to inspect tubing and other structures for applications such as pipelines of gas and oils, nuclear reactors, chemical manufacturing, and municipal water systems. Compact and portable eddy current testing equipment is used for on-site inspections in the field, such as looking for cracks in bridges and in aeroplane components from wings to the landing gear. That makes ECT, and other methods of nondestructive testing, highly important to public safety playing a role in helping to prevent destructive events like pipeline breaks, bridge collapses, and plane crashes.

FAQs (Frequently Asked Questions)

1. What is Eddy Current Induction?

Ans: The eddy current induction is the generation of current due to small current loops as a result of the change in magnetic flux.

2. Why is it termed as Eddy Current?

Ans: When the conductor encounters the change in the magnetic flux, then the free electrons present in the conductor will experience a magnetic force. As a result of the effect of the magnetic force on the free electrons, these free electrons will move in the form of small loops or eddies, the electric current generated due to the motion of free electrons in the form of eddies is known as the eddy current.