EMF Of Mutual Inductance

 In 1831, Michael Faraday published a scientific paper on electromagnetic induction and created Faraday’s law, which aids in the prediction of magnetic field interactions with electrical circuits in order to generate an EMF (electromotive force). Self-inductance and mutual inductance are the two major forms of inductance.Faraday’s law of induction says that a voltage or EMF is induced in a conductor across a circuit as a result of magnetic field changes, and this is the process known as electromagnetic induction. Lenz’s law states that if the charge flux can be increased or decreased from the coil, the coil has the capacity to induce current. The mutual inductance formula in terms of current and emf, as well as the emf of the transformer from mutual inductance, were reviewed in this article.

What Is The EMF Of Mutual Inductance?

Magnetic induction, also known as electromagnetic induction, is the creation of an electromotive force across an electrical conductor in a magnetic field. It may be used in transformers, inductors, generators, electric motors, and many other devices.

Mutual inductance is an EMF (electromotive force) created when the magnetic field of one coil or loop opposes voltage and current changes in another loop, indicating that both coils are magnetically coupled due to the change in magnetic flux. The amount of the EMF produced is related to the change in current rate of a coil.

The formula for mutual inductance is;

M= NΦ/I

where, M represents mutual inductance, N represents number of coils or loops, Φ

represents magnetic flux and I represents the current induced. Kg.m2.s-2.A-2 is the S.I.

unit of it.

Mutual Induction Formula In Terms Of Current And Emf

The EMF of Mutual Inductance is described by Faraday’s law and is always in the

direction opposite to that of the magnetic field which is produced by the coil (coupled

loop or coil). The self inductance induces the electromotive force (EMF) in the coil 1

while in coil 2, the EMF is caused by current change I1. Considering the 1st coil with

turns N1, magnetic field B and current I1 while 2nd coil with turns N2 and current I2. 

Due to closeness of both the coils, some of the lines of magnetic field will also pass through

the 2nd coil with the mutual inductance M21 which represents the mutual inductance of

2nd coil with regard to 1st coil. Φ21 will be the magnetic flux due to I1 in the second coil’s

1 turn.

The EMF of Mutual Inductance for 2nd coil can be represented by the formula;

EMF = -N2A (∆B/∆t) = -M (∆I1/∆t)

where, M represents proportionality constant between generated EMF in 2nd coil to

current change in 1st coil.

EMF Of Transformer From Mutual Inductance

Transformer is an electronic device that has mutual inductance as its basic principle. 

The ability of an electronic device to store energy as an electromagnetic field intensity is called inductance. A device capacity to create reactance to resist a changing current (self-induction) or to generate a current (mutual induction) in an adjacent circuit is referred to as induction. 

The current in the coil creates a field around the conductor that grows outwards. That field holds energy. The energy stored in the electromagnetic field is reconverted to electrical energy in the coil wires when the source voltage is reduced from its maximum to zero. Variations in the dc source are really repelled by the energy.

The emf of transfer from mutual inductance is also known by the name of coefficient of coupling. The coefficient of coupling is a physical quantity that measures how efficient the process of power transmission is taking place from the primary coil into the secondary coil.

The power transmission process is ideal when the coefficient of coupling’s value becomes one. When no power transmission process is taking place, the coefficient of coupling’s value becomes zero. The design of a transformer plays a significant role in affecting the coefficient of coupling variations. 

The position of one coil with respect to the other coil is one of the most essential factors. If one coil gets wounded over the other coil, and along with this the emerging flux from the primary coil is also bisecting through the flux generated from the second coil, then the coefficient of coupling gets near to one. 

If the intersection of flux stops occurring, then the coefficient of coupling starts approaching zero. The coefficient of coupling of conventional transformers begins from 0.94 to 0.98.

Conclusion

The EMF of Mutual Inductance is described by Faraday’s law and is always in the

direction opposite to that of the magnetic field which is produced by the coil (coupled

loop or coil). Mutual inductance is an EMF (electromotive force) created when the magnetic field of one coil or loop opposes voltage and current changes in another loop, indicating that both coils are magnetically coupled due to the change in magnetic flux. You got the working principle of the emf of the transformer from mutual inductance, and when to use mutual inductance formula in terms of current and emf.