This Slide is about the Electromagnetic Induction System, who people don't know about that system it will help them some basic ideas about Induction system. Now a days we are looking for alternate fuel to protect our environment form pollutions that why we can use the Induction motor for operate our vehicle, as we will use this system for our daily works we have to know about this one.............
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1. Here, I am trying to present about Electromagnetic
Induction.
2. OBJECTIVES:- (note: they are very shortly briefed ) After
complete that lecture we will be able to:- Get some information
about Electromagnetic Induction system. What are the requirements
for Electromagnetic Induction. We will know about the amount of
Induced e.m.f. We will know about Faradays low of Electromagnetic
Induction. Direction of Induced e.m.f. (Lenzs Law & Fleming
Right Hand Rule)
3. When the Magnetic flux linking with a conductor or coil and
changes an e.m.f. is induced in the conductor. If the conductor
forms a complete loop or circuit, a current will flow in it, thats
called the Electromagnetic Induction.
4. The basic Requirements for Electromagnetic Induction:- 1)
The first and basic requirement for electromagnetic induction is
the change in Flux linking with the conductor (or coil). 2) The
e.m.f. and hence the current in this conductor (or coil) will
persist so long ass this change is taking place.
5. Some other important Requirements are The requirement is not
only linking the coil with the Flux, the main thing is, if we want
to induced some e.m.f. The Flux should be change after linking with
coil. No change of Flux ,No e.m.f. Induced in the coil. The change
of Flux linking with the conductor and Flux can be cutting in two
ways:-
6. 1) One of them The conductor will moved and the magnetic
field will Stationary. Use that system the DC generator works.
7. 2) Secondly, The conductor will stationary and the Magnetic
field will be moved. That is used for the AC generator.
8. The term N is called flux linkages with Coil. Thus emf
induced in a coil is directly proportional to the rate of change of
flux linkages. In the same rate of changes flux if we increase the
turn of coil then the rate of induced emf will be increase.
9. Amount of Induced e.m.f: The amount of induced e.m.f. in a
coil is directly proportional to-- -- 1) the number of turn on the
coil, 2) the rate change the Flux linking with coil. Induced emf is
Here, N= Number of Turn of Coil = the change of Flux linking by
conductor t= time of changing the flux t NN t N
eortheChangTimeTakenf uxChangeofFl N geofFluxrateofChanN 12
)12(
10. Faradays Law of Electromagnetic Induction:- Faraday
performed a series of experiments to the phenomenon of
electromagnetic induction. He performed two laws about
electromagnetic induction a known as Faradays law:- First Law: When
the Changes Flux linking with a conductor or coil, an emf is
Induced in it. Second Law: The magnitude of induced emf in a coil
is directly proportional to the rate of change of flux
linkages
11. Induced emf Rate of change of flux linksges. Consider a
magnet approaching towards a coil. Here we consider two instants at
time T1 and time T2. Flux linkage with the coil at time, T1 = N1 Wb
Flux linkage with the coil at time, T2 = N2 wb Change in flux
linkage = N(2 1) Let this change in flux linkage be, = 2 1 So, the
Change in flux linkage = N Now the rate of change of flux linkage =
N / t Take derivative on right hand side we will get The rate of
change of flux linkage = Nd/dt But according to Faradays law of
electromagnetic induction the rate of change of flux linkage is
equal to induced emf
12. Direction of Induced emf and Current: The direction of
Induced emf and hence current in conductor or coil can be
determined by one of the following methods: 1. Lenzs Law 2.
Flemings Right hand Rule. 1) Lenzs Law:- Email Lenz, observed that
the direction of induced emf has a defined relation to change of
magnetic field that produces it. He gave the simple following
simple rule:-
13. An Induced Current will flow in such a Direction so as to
oppose the cause that produces it. The cause that the change of
produces current is the change of flux linking the coil. Therefore,
the direction of induced current will be such that its own magnetic
field oppose the change in flux that produced the induced current.
That means the induced current on its conductor or coil will be the
oppose direction of the original flux direction.
14. We know that, the magnetic flux always flow through from
North pole to South pole. So, Current will be flow through from
South to North.
15. 2) Flemings Right Hand Rule:- This is the Rule of
particularly suitable to find the direction of Induced emf and
hence current when the conductor moves at right angles to a
stationary magnetic field. Stretch out the Four finger, Middle
finer and thumb of Your right hand so that they are at right angles
to one another.
16. If the forefinger points to direction of the magnetic
field, Thumb is the direction of motion the conductor, then the
middle finger will point in the direction to the Induced
Current.
17. Explanation of Flemings Right Rule:- Consider that, A
Conductor is Moving as the direction of Forefinger, the magnetic
flux is go through from the north to south pole as the same
direction of Thumb finger, now Current will be flow as the same
direction of the middle finger.
18. Let, ABCD is a conductor and it is moving through in Clock
wise direction magnetic fluxs are going from north pole to south
pole. When the conductor is moving flux is cutting by it. When flux
is cutting emf is induced by conductor. On the time ABCD conductor
is in vertical position flux is cutting and emf induced from DCBA
in conductor and it is passing through by the Commutator, the
conductor have two terminals there have two carbon brush with two
commutators. Commutator is moving With the conductor and induced
emf (Current) is passing through by carbon brush to the
circuit.
19. After moving sometimes the conductor will in parallel
condition, so no flux will be cut by the conductor and no emf will
induced in conductor. So, no current will flow. Again when the
conductor will be in vertical position on this time magnetic flux
will be cut by conductor but this time will be flow the negative
current by conductor. And current will be flow from ABCD. The
current flowing curve for a full cycle will be like the showing in
the figure. That getting current is called AC current.