Electromagnetic Induction Faradays Law

1
Electromagnetic InductionFaradays Law
The Generation of Electricity
2
Induction Applets
Electromagnetism
3
Gravitational Field (g)

• Two ways to think about it

accel.
Fg /m
(m/s2)
(N/kg)


kg
g 9.8 N/kg 9.8 m/s/s
4
Electric Field (E)

• Two ways to think about it

DV /Dd
Fe /q
(V/m)
(N/C)
FIELD GRADIENT
FORCE PER CHARGE



5
Magnetic Field (B)

• Three ways to think about it

Tesla Force per length of current carrying wire
Tesla Force per moving charge
F flux (Weber)
FLUX DENSITY
6
Flux Density
FLUX DENSITY
F flux (Weber)
A area (m2)
1 Wb
Weber
1 TESLA
m2
m2
7
E-M INDUCTION
FB

FE
F E FB
metal rod
Eq Bqv
DV BvL
E DV/L
DV/L Bv
8
E-M INDUCTION
DV BvL
If there is a complete circuit, this induced
voltage will produce an induced current.
INDUCED VOLTAGE (EMF)
Ei IiR
(Ohms Law)
Ei BvL sin Q
Q angle between B and v
9
UNIT CHECK
Ei BvL sin Q
Volt
tesla
(m/s) m
Volt
N/Am
(m/s) m
Volt
(m/s)
N/C/s
Volt
Nm/C
J/C
Volt Volt
10
UNIT CHECK
Ei BvL sin Q
Volt
m
Volt
(Rate of cutting B flux)
Ei DF/Dt
11
FARADAYS LAW(2 FORMS)
Ei BvL sin Q
Ei DF/Dt
?
L3
12
LENZS LAW
The direction of the induced current will always
oppose the change which induces it!
?????????
NO FREE LUNCH!!
13
RHR 3 FB ON I or q
Thumb Current Fingers B Flux Palm Force
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RIGHT HAND RULE
Thumb Current Fingers B Flux Palm Force
Thumb Motion of Fingers B Flux Palm
Force
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Induction Demos

• Ei in straight wire through permanent magnet
• Ei in a coil
• Move magnet
• Move coil
• Primary/Secondary Coil
• Power supply move coil/core
• DC turn on/off
• AC watch vibrate
• Generators Back torque
• Big Model
• Genecons
• Lenzs Law
• Hanging rings (cut/whole) with permanent magnet
• Jumping Ring
• Aluminum Pipe with permanent magnet
• Transformers
• AC
• DC Jacobs Ladder

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Electromagnetic Induction Lenzs Law
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Galvanometer
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Electrical Generator
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AC Generator
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(No Transcript)
21
FLUX ENCLOSED BY COILS IS MAXIMUM
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FLUX ENCLOSED BY COILS IS ZERO
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GENERATOR AC/DC
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GENERATOR DCSPLIT RING COMMUTATOR
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GENERATOR ACSPLIT RING COMMUTATOR
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GENERATOR ACSPLIT RING COMMUTATOR
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FARADAYS LAW(2 FORMS)
Ei BvL sin Q
Ei DF/Dt
?
L3
28
LENZS LAW
The direction of the induced current will always
oppose the change which induces it!
?????????
NO FREE LUNCH!!
29
LENZS LAW
Induced force opposes your effort

Ii
Ii induced current
MAKES YOU WORK FOR THE ELECTRIC ENERGY YOU
GENERATE
NO FREE LUNCH
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Demo Hanging Ring
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PIPE DEMO
Ei DF/Dt
INDUCED CURRENT
Ii
Ii
Ei DF/Dt
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Jumping Ring
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Jumping Ring
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Induction Record Player Stylus
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Induction Record Player Stylus
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Induction Microphone
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Induction Electric Guitar
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Induction Tape Head