Upload
faadumomizankaahiye
View
222
Download
0
Embed Size (px)
Citation preview
8/12/2019 Magnetism&Motors.pdf Form 2
1/30
The earth is a giant magnetMagnetic field lines
of forceleave the north poleand enterthe south pole Whatis a magnetic field?
8/12/2019 Magnetism&Motors.pdf Form 2
2/30
Magnetic field
The space around a magnet where
the forces of attraction and repulsion
act is the magnetic field. A magnetic
field is made up of lines of force.
8/12/2019 Magnetism&Motors.pdf Form 2
3/30
8/12/2019 Magnetism&Motors.pdf Form 2
4/30
8/12/2019 Magnetism&Motors.pdf Form 2
5/30
Magnetic flux patterns
8/12/2019 Magnetism&Motors.pdf Form 2
6/30
Magnetic?
These materials along
with certain other alloys arecalled ferromagnetic materials.
8/12/2019 Magnetism&Motors.pdf Form 2
7/30
Hard or soft material?
Iron has stronger inducedmagnetism.
Steel has a weaker induced
magnetism.
8/12/2019 Magnetism&Motors.pdf Form 2
8/30
Hard or soft?
8/12/2019 Magnetism&Motors.pdf Form 2
9/30
Hard or soft?
Iron is a magnetically soft material.
Strong but temporary!
Steel is a magnetically hard material.
Weak but permanent!
8/12/2019 Magnetism&Motors.pdf Form 2
10/30
Induced magnetism
8/12/2019 Magnetism&Motors.pdf Form 2
11/30
8/12/2019 Magnetism&Motors.pdf Form 2
12/30
Making magnetsDouble touch method
The end where the stroking pole
leaves the bar
becomes the opposite pole.
M ki t
8/12/2019 Magnetism&Motors.pdf Form 2
13/30
Making magnets:can a magnet have similar poles at its ends?
Consequent poles
The end where the stroking pole
leaves the bar
becomes the opposite pole.
8/12/2019 Magnetism&Motors.pdf Form 2
14/30
The Domain Theory of magnets
Magnetic material
In demagnetized
condition
Magnetic material
In magnetized
condition
Dipoles inmagnetic
domains
8/12/2019 Magnetism&Motors.pdf Form 2
15/30
8/12/2019 Magnetism&Motors.pdf Form 2
16/30
Domain theory explains:1. Demagnetization: mechanical vibrations can cause demagnetization
2. Magnetic saturation: strength of a magnet cannot be increased beyond a certain limit.3. Breaking a magnet: breaking a magnet
the broken ends maintain the poles.
8/12/2019 Magnetism&Motors.pdf Form 2
17/30
Magnetic keepers
8/12/2019 Magnetism&Motors.pdf Form 2
18/30
Magnetic effect of current
8/12/2019 Magnetism&Motors.pdf Form 2
19/30
8/12/2019 Magnetism&Motors.pdf Form 2
20/30
Direction of the magnetic field
Grip the wire with your right hand,the field lines will go in the direction
of the fingers.
8/12/2019 Magnetism&Motors.pdf Form 2
21/30
Magnetic effect of an electric current
Magnetic flux pattern due to a current
in a long straight wire,
8/12/2019 Magnetism&Motors.pdf Form 2
22/30
Magnetic flux pattern due to a current
in a short circular coil of wire.
Magnetic effect of an electric current
Use the right
hand grip rule
8/12/2019 Magnetism&Motors.pdf Form 2
23/30
Magnetic effect of an electric current
Magnetic flux
pattern due to acurrent in a
solenoid.
Grip the solenoidwith the right hand
with the fingers in
the directionof the current
The thumb points
to the north pole
Di ti f th ti fi ld
8/12/2019 Magnetism&Motors.pdf Form 2
24/30
Direction of the magnetic field
Grip the wire with your right hand,the field lines will go in the direction
of the fingers.
8/12/2019 Magnetism&Motors.pdf Form 2
25/30
Kicking wire experiment
8/12/2019 Magnetism&Motors.pdf Form 2
26/30
Force on conductor
Field due to
permanent
magnet
Field due to
current
in wire
Two fields interact
to produce
force (motion)
8/12/2019 Magnetism&Motors.pdf Form 2
27/30
Flemings left hand rule
Used to determine
direction of motion of conductor
8/12/2019 Magnetism&Motors.pdf Form 2
28/30
d.c. electric motor
8/12/2019 Magnetism&Motors.pdf Form 2
29/30
Fields interact, coil turns
8/12/2019 Magnetism&Motors.pdf Form 2
30/30
END OF MOTORSFOR NOW
Go back and review..
remember
u can not sleep if u dont know it.
sweet dreams