The document discusses electromagnetic induction and Faraday's laws of induction. It begins by introducing electromagnetic induction and how an EMF can be induced by changing magnetic flux. It then describes Faraday's two laws of induction and provides examples of induced current. The document outlines two types of induced EMF: dynamically induced EMF which occurs due to physical movement between a conductor and magnetic field, and statically induced EMF which occurs due to changing flux through a coil without physical movement. It further explains self-induced and mutually induced EMF as types of statically induced EMF.

1. CHAPTER NO.:-2
ELECTROMAGNETIC INDUCTION
MR.KARTIK K. PATEL
(B.E.-ELECT. ENGG.)
(LECT. IN EE DEPT.-VPMP
POLYTECHNIC)

2. TOPICS:-
INTRODUCTION
FARADAY’S LAWS OF
ELECTROMAGNETIC INDUCTION.
DYNAMICALLY INDUCED EMF
FLEMING’S RIGHT HAND RULE
STATICALLY INDUCED EMF
1. SELF INDUCED EMF
2. MUTUALLY INDUCED EMF

3. The Histor y of
Induction:
“In 1831 Joseph Henry discovered magnetic induction.” Joseph Henry
“ Michael Faraday's ideas about conservation of energy led (1797-1878)
him to believe that since an electric current could cause
a magnetic field, a magnetic field should be able to
produce an electric current. He demonstrated this
principle of induction in 1831.’’
So the whole thing started 180 years ago
Michael Faraday
(1791-1867)

4. 1. INTRODUCTION:
THE PHENOMENA OF ELECTROMAGNETI
INDUCTION ARE VERY IMPRTANT FOR THE
STUDY OF THE WORKING PRINCIPLE OF THE
ELECTRICAL MACHINES.
THE ELECTRICAL M/C LIKE DC
MOTOR, DC GENERATOR, INDUCTION
MOTOR, TRANSFORMER, ALTERNATOR
WORKS ON INDUCTION PRINCIPLE.

5. ELECTROMAGNETIC INDUCTION:
How to Induce an EMF?
An emf can be induced whenever there is a
change in flux.

6. Relative motion between a magnet
and a coil
Conductor moving in the magnetic field

7. 2. FARADAY’S LAWS OF
ELECTROMAGNETIC INDUCTION:
Michael Faraday
(1791 – 1867)

8. FARADAY’S LAWS:-
THERE ARE TWO LAWS OF
FARADAY’S RELATED TO
ELECTROMAGNETIC
INDUCTION AS STATED
BELOW:

9. FARADAY’S FIRST LAW:-
“WHEN A CONDUCTOR CUTS THE MAGNETIC
FIELD, THE EMF INDUCED IN THAT
CONDUCTOR.’’

10. 2.FARADAY’S SECOND LAW :
“THE MAGNITUDE OF EMF INDUCED IN ANY
CONDUCTRO IS EQUAL TO THE RATE OF
CHANGE OF FLUX LINKAGES WITH IT.”

11. FARADAY’S LAW:-
If we change the magnetic flux through a coil of N
turns, an induced emf appears in every turn and the
total emf induced in the coil is the sum of these
individual induced emfs.

12. F araday’s Law for a Single
Loop :
dΦ
E =ε=−
dt

13. Faraday’s Law for a coil
having N turns :
dΦ
E = ε = −N
dt

14. Examples of Induced Current:-
Any change of current in primary
induces a current in secondary.

15. Direction of Induced Current
Bar magnet moves through coil
S N
 Current induced in coil v
Reverse pole
 Induced current changes sign N S
v
Coil moves past fixed bar magnet
 Current induced in coil S N
Bar magnet stationary inside coil N S
 No current induced in coil

16. 3. TYPES OF INDUCED EMF:-
THERE ARE TWO TYPES OF INDUCED EMF:-
1.DYNAMICALLY INDUCED EMF
2.STATICALLY INDUCED EMF
SELF INDUCED EMF
MUTUALLY INDUCED EMF

17. 3.1 DYNAMICALLY INDUCED EMF:
Definition:-
“T he EMF Induced in the coil due to the
physical movement of the magnetic field
or coil is known as Dynamicall y Induced
EMF.”

18. Consider a conductor A of length L meters placed in
uniform magnetic field of flux density B wb/ m2
area =l*dx
flux difference=Bldx
E=Bldx / dt
But velocity,
V =dx/dt
So ,
E=Blv volt.
E=Blv*sinO

19.  CONDITIONS FOR PRODUCTION
OF DYNAMICALLY INDUCED EMF:-
• FOLLOWING THREE CONDITION :-
•Presents of magnetic fields
•Presents of conductor
•Relative movement of magnetic field and conductor

20. 2) Statically induced Emf:-
Definition:-
“ There is no physical motion of conductor but due the flux,
the flux link with the coil is changed and so emf induced in
the coil. This emf is called statically induced emf.”
There are two types of statically induced EMF:-
1)Self induced emf
2)Mutually induced emf

21. 1) Self induced EMF:-
Definition:- “ The emf induced in the coil due
to change its own flux linked with is known
as self induced emf.”
-Conductor remains stationary and flux
linked with it is changed. (the current which
creates the flux changes i.e increases or
decreases).
-

22. Consider a coil having N turns as shown in fig, when the current
flowing through is, a flux will produced in the iron core. So the
flux link with coil changes from its initial value of Φ 1 to final
value of Φ2 wb in time t second.

23.  self inductance:-
“ The property of the coil oppose the change in current or flux is
called self inductance.”
Co-efficient of self inductance:-
“The co-efficient of self inductance is defined as the ratio of flux
link with the coil to the current flow in coil.”
It is denoted by L.
Its unit is Henry (H).

24. B(t)
i
~
Consider a coil having N turns. When the current I
flowing through it, it will produced the flux.
Φ
Hence B co-efficient of self inducance is given by,
L ≡ the
di
I
ε ε = −L
L≡−
(dI / dt ) dt
L = µ o n A = µ o n V
2 2

25. 2) Mutually induced EMF:-
“ The emf induced in one coil due to the change in flux of anther
coil linked with it. Is called mutually induced emf.”
if current changes in coil #1, an emf is induced in coil #2
ε 2 = −N
d Φ1
dt
Φ∝B
B ∝ I1
rewrite as:
ε 2 = −M
dI1
dt
M is the “mutual inductance”

26. 2) Mutual induction:-
“ The property of the coil to produce the emf in
anther coil placed nearer to them when the current
flowing through the first coil changes is known as the
mutual inductance.
•It is denoted by M.
•Its unit is Henry(H).

29. Compare the dynamically
induced emf with statically
induced emf:-
Dynamically emf: Statically emf:
“the emf induced in the coil “ the emf induced in coil
due to physical movement due to the flux linked with
of the magnetic field or coil the coil changes is called
is called dyamically emf. statically emf.”
E=Blv sino volt 
In this type of emf there is In this type of emf there is
physical motion of no any physical motion of
conductor. conductor.
Example: alternator, d.c Example:- induction
generator. motor, transformer.

30. Thanks all of
you….