This document is a lecture on electromagnetic induction covering key topics like direction of induced EMF, Lenz's law, nature of induced EMF, applications of dynamically induced EMF, statically induced EMF, self induced EMF, and mutually induced EMF. It compares statically and dynamically induced EMF and provides an exercise at the end assessing understanding of mutually induced EMF, Lenz's law, Fleming's right hand rule, self induced EMF, and the difference between dynamically and statically induced EMF.

1. Matoshri Aasarabai
Polytechnic, Eklahare
Nashik.
Class – SYME (ME3I)
Basic Electrical And Electronics Engineering
(BEE)
Subject Code-22310
Lecture-3
Course Instructor: Mrs K. B. Bodke
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2. Topics covered in last video
• MMF
• Magnetic Force
• Permeability
• hysteresis loop
• reluctance
• B-H curve
• Analogy between electric and Magnetic
circuits.
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3. Topics To be covered in this video
• Electromagnetic Induction
• Direction of Induced Emf
• Lenz’s law
• Nature of induced emf
• Applications of dynamically induced emf
• Statically Induced EMF
• Self induced emf
• Mutually Induced EMF (M)
• Comparison of Statically and Dynamically
induced EMF
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4. Electromagnetic Induction
• It is the phenomenon of voltage induction in a
conductor which is placed in a magnetic field
• The generation of emf due to electromagnetic
induction was first obtained by scientist
Michael Faraday
• Michael faraday then formulated two laws of
electromagnetic induction
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5. Electromagnetic Induction
• Faraday’s First laws of electromagnetic
induction
• Faraday’s Second Law:
• Flux linkage= Flux* Number of turns of coil
• Expression for induced emf
e= N dφ/ dt volts
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6. Direction of Induced Emf
1) To use the
Fleming’s right
hand rule
2) To use the Lenz’s
law
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7. Lenz’s law
• The direction of induced emf produced due to
the process of electromagnetic induction is
always such that , it will set up a current to
oppose the basic cause responsible for
inducing the emf.
• e= - N dφ/ dt
• Negative sign indicates that induced emf
opposes the cause producing it
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8. Nature of induced emf
1) Dynamically induced emf- an emf induced
due to a physical movement of either
conductor or flux .
2) Statically induced emf- An emf is induced not
due to any physical movement but it is due to
the change in flux associated with the coil by
increasing or decreasing the current that
produces flux
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9. Magnitude of Dynamically induced
emf
• The conductor moves in a plane which is
parallel to the magnetic flux therefore it does
not cut any magnetic flux hence the induced
emf is zero
• The plane of direction of motion of the
conductor is perpendicular to the plane of
magnetic flux therefore the cutting of
magnetic flux is maximum and induced emf in
conductor is maximum
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10. Expression for the Magnitude
• When the plan of motion of
the conductor is exactly
perpendicular to the flux the
induced emf is given by
e=Blv Volts
Where, B= Flux Density
L= conductor length
V= velocity
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11. Expression for the Magnitude
• But if the plane of motion
of the conductor is not
exactly perpendicular to
the plan of flux then the
expression for the
induced emf is given by,
e= BlvSinθ
Where, θ= The angle
between plan of flux and
direction of conductor
movement
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12. Applications of dynamically induced
emf
1) DC Generator
2) Back emf of dc motor
3) Induction Motor
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13. Statically Induced EMF
• This is the another technique of generating
emf. In this technique neither conductor nor
the magnetic field are physically moved for
emf generation. Both of them are stationary.
There are two Different types of Statically
induced emf
1) Self induced Emf
2) Mutually induced EMF
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14. Self induced emf
• Flux linkage with coil=
N*φ
• Due to change in flux
linkage with the coil an
emf is induced into the
coil as per faradays law .
This emf is induced into
the coil as per the
faradays law. This is
called as the self
induced emf
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15. Self inductance
• As per the faraday’s law of electromagnetic induction
the magnitude of self induced emf in a coil due to
change In current flowing through it is given by
• e= -N dф/ dt volts
• Negative sign indicates that the self induced voltage
opposes the change in current through the coil and it
produces flux then the self inductance is given by
• Inductance(L)= N*ф/I
• By substituting ф=L*I/N
• e= -L[dI/dt] volts
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16. Mutually Induced EMF (M)
• In mutually induced Emf
two or more coils are
involve
• Two coils placed near each
other
• Flux produced by one coil
gets linked with another coil
and due to the change in
the flux produced by the
coil c1 if there is induced
emf in the second coil then
such emf is known as
mutually induced emf
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17. Mutually Induced EMF (M)
• Expression For mutual inductance is
• M= N2ф2 / I1 or M= N1ф1/ I2
• Where N1 and N2 are the number of turns of
coils and I1 and I2 are the current flowing
through them
• Ф1 is the flux produced by I1 in c1 and ф2 is
flux produced by I2 in C2
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18. Comparison of Statically and
Dynamically induced EMF
Characteristics Dynamically induced emf Statically induced emf
Movement of coil or
magnet
Either coil moves or
magnet moves
Neither coil nor magnet
moves
Current through
electromagnet
Can remain Constant Must vary with respect to
time
Expression for induced emf e= Blvsinθ e=-L di/dt or N dф/dt
Applications DC generator, back emf in
DC motors, Induction
motors
Transformer
Example Emf induced in a generator Emf induced in a
transformer winding
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19. Summary
• Electromagnetic Induction
• Direction of Induced Emf
• Lenz’s law
• Nature of induced emf
• Applications of dynamically induced emf
• Statically Induced EMF
• Self induced emf
• Mutually Induced EMF (M)
• Comparison of Statically and Dynamically
induced EMF
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20. Exercise 1.3
• Define mutually induced emf
• What is the difference between self induced
emf and mutually induced emf
• State and explain fleming’s right hand rule
• State and explain lenz’s law
• What is the difference between dynamically
induced emf and statically induced emf
• Explain the concept of self induced emf
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21. Thanks for watching the video
• For any queries contact me on:
komalavhad21@gmail.com
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