Elements Of Electrical Engineering(2110005)

1. ALA PRESENTATION
TOPIC : “Magnetic Circuit & Energy Stored In Magnetic Field”
Branch : Mech I-3
Prepared By: Jani Parth (150120119051)
Guided By: PRO. Hitesh Manani

2.  Contents
1.Magnetic Circuit
2.Important Terms Regarding Magnetic Circuit
3.Series Magnetic Circuit
4.Parallel Magnetic Circuit
5. Magnetic Leakage And Fringing
6.Energy Stored In Magnetic Field

3. 1. Magnetic Circuit
in this fig show an iron ring of length ‘l’m and cross area ‘A’ m. a coil having
N number of turns is wound over the iron ring. When this coil carries a
current, a magnetic field is produced inside the ring. This is called its
magnetics circuit.

4. 2. Important Terms Regarding Magnetic Circuit
Magneto motive Force (mmf)
in a magnetics circuit, the magneto motive forse (mmf) is required to
produce flux. The mmf is given by the product of the current through the
coil and the number of turns of the coil.
i.e. mmf=NI
Unit Is Ampere-turns And Is Dinoted By Fm.
Ampere-turn (AT)
It Is Unit Of Magneto motive Force (mmf) And Is Given By The
Product Of Number Of Turn Of A Magnetics Circuit And Cur-
Rent In Amperes In Those Turns.

5. Magnetic field strength or magnetic field intensity (H)
we want to find the magnetic field intensity a point X which lies in
air stop at a distance of ‘d’ metres from a pole of strength m
webers as in fig

7. Reluctance
It Is Property Of Magnetic Material Which Opposes The Creations Of
Magnetics Flux In It. It Is Analogous To Resistance In An Electric Circuit.
Its Unit Is AT/Wb.
Permrance
in electromagnetism, permeance is the inverse of reluctance.Permeance is
a measure of the quantity of flux for a number of current-turns in magnetic
circuit.

8. 3.Series Magnetic Circuit
The Series Magnetic Circuit is defined as the magnetic circuit having
number of parts of different dimensions and materials carrying the same
magnetic field.

10. 4.Parallel magnetic circuit
the total flux ǿ set up by the coil divides at B into parallel pathe BE and
BCDE.
The Total Mmf Required To Create Flux Ǿ Is Equal To The Sum Of Mmf In
Path Abef And Mmf In Path Be Or Path Bcde.
Total Mmf = mmf for path ABEF + mmf for path be or BCDE

11. 5. Magnetic Leakage And Fringing
leakage flux is the flux which does not follow the desired path in a
magnetic circuit.
A large part of flux path is through a magnetic material ans remaining part
of flux path is through air.