Current carrying conductor in a magnetic field.

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Current carrying conductor in a magnetic field.
A current carrying conductor in a magnetic field
experiences a ..................... The direction
is given by ....................
............. . ............. Motor rule.
Force
N
S
Fields in ...............................
direction they cancel out/become weakened -
resulting in a downward force.
X
2
Current carrying conductor in a magnetic field.
A current carrying conductor in a magnetic field
experiences a force. The direction is given by
Flemmings Left Hand Motor rule.
Force
N
S
Fields in opposite direction they cancel
out/become weakened - resulting in a downward
force.
X
3
Right Hand Wire Rule
4
Magnetic Effect

• A .............................. field is
  generated around any conductor when an electric
  current flows through I t.

Electric current
Wire with current coming ......................
you
Wire with current going ............... from you
x
5
Magnetic Effect

• A magnetic field is generated around any
  conductor when an electric current flows through
  it.

Electric current
Wire with current coming towards you
Wire with current going away from you
x
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SOLENOID

• A coil generates a very concentrated (strong)
  magnetic field in its center.

Increasing the number of coils strengthens the
magnetic field. The .............. Hand Rule can
also be applied to a solenoid!
Electric current
N
x
S
INSIDE THE COIL THE FIELD GOES FROM
...............TO ..............!!!
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SOLENOID

• A coil generates a very concentrated (strong)
  magnetic field in its center.

Increasing the number of coils strengthens the
magnetic field. The Right Hand Rule can also be
applied to a solenoid!
Electric current
N
x
S
INSIDE THE COIL THE FIELD GOES FROM SOUTH TO
NORTH!!!
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Right Hand Rule - Solenoid
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Solenoid Field

• Web Applet Demogtgt

• Note field same as bar magnet
• Inside S ? N!!!!!

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THE ELECTRIC MOTOR
N
S
current
B
C
A
D
-

• Indicate the direction of rotation with an arrow.
• Show the application of the rule used to decide
  which way the coil will turn.

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THE ELECTRIC MOTOR
Rotation
S
N
current
B
C
Thrust
A
D
-

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THE MOTOR EFFECT
-

A current carrying conductor in a magnetic field
experiences a . The direction is given by
.. rule.
N
S
Second
Forefinger
Magnetic fields ..
Thumb
N
S
Fields in opposite direction they
- resulting in a .. force.
X
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THE MOTOR EFFECT
-

A current carrying conductor in a magnetic field
experiences a force. The direction is given by
Fleming's Left Hand Motor rule.
N
S
Second
Forefinger
Force
Magnetic fields strengthened!
Thumb
N
S
Fields in opposite direction they cancel
out/become weakened - resulting in a downward
force.
X
X
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THE ELECTRIC MOTOR

• Indicate the polarity of the battery.
• Show how the direction of rotation supports your
  decision.

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THE ELECTRIC MOTOR

• -

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(No Transcript)
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Electromagnetic Induction
-

An electrical conductor that is accelerated
through a magnetic field will experience an
.. .electrical current according to
Fleming's .................Hand Rule.
.............. current
N
S
............
Thumb
Second
.................
.................
..
Forefinger
Faradays Law The size of the induced .is
directly proportional to the .of change of
the magnetic .. .
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Electromagnetic Induction
-

An electrical conductor that is accelerated
through a magnetic field will experience an
INDUCED electrical current according to Fleming's
Right Hand Rule.
N
S
Thrust
Thumb
Second
Current
Field
Thrust
Forefinger
Faradays Law The size of the induced current is
directly proportional to the rate of change of
the magnetic flux linkage.
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Electric Field Strength
-

Magnetic field Strength (B) measured in
()
(.)
(...)
N
S

• Total number of field lines is called ..
  (.) measured in . ()
• ? .
• ? .. ()
• B . ()
• A . through which flux passes

Thrust
(..)
? no of . in that area.
1 .. is the field . when a current of
.. A flows through a conductor and it
experiences a .. of N per meter of length.
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Electric Field Strength
-

Magnetic field Strength (B) measured in Teslas
(T)
(1A)
(1T)
N
S

• Total number of field lines is called magnetic
  flux (?) measured in Webers (Wb)
• ? BA
• ? magnetic flux (Wb)
• B magnetic field strength (T)
• A area through which flux passes

Thrust
(1N)
? no lines in that area
1 Tesla is the field strength when a current of 1
A flows through a conductor and it experiences a
force of 1N per meter of length.
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Faradays Law
The induced emf (.) is directly proportional to
the . of change of ..

• The induced emf can be increased by
• Increasing the
• Using
• Decreasing the . moving ..

The size of the induced is (also) directly
proportional to the . of the
...
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Faradays Law
The induced emf (?) is directly proportional to
the rate of change of flux linkage (?).

• The induced emf can be increased by
• Increasing the number of coils
• Using stronger magnets
• Decreasing the time moving faster

The size of the induced current is (also)
directly proportional to the rate of change of
the magnetic flux linkage.
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Generator - .........................

• current is produced.

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Generator - Alternator

• Alternating current is produced.

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Generator - .......................

• current is produced.

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Generator - dynamo

• Direct current is produced.

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Alternating Current

• Voltage current . constantly.

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Alternating Current

• Voltage current vary constantly.

Coil vertical 90o to the magnetic field
0o 90o 180o 270o 360o
V vmax sin 2?ft I Imax sin 2?ft
A maximum current would be produced at the same
time as the maximum voltage.
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Alternating and Direct Current

• What would be the equivalent constant/direct
  current /voltage to give the same effect as an
  alternating current?

X
X
??
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Equivalent voltage/current
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Equivalent Voltage Root Mean Squared
Vmax 2
V2
Vmax2 2
Vmax2 ave (mean)
Voltage (V)
V
Exemplar Questionsgtgt Revision Questions gtgt

• Pav VRMSIRMS or P I2RMS R

32
Resistance
16.97 V
12 V
Io Vrms/R .. ..
Io Vo/R ..
V

5 ?
R Vrms /Irms . ...
R Vo/Io
Resistance can be worked out either way!

• Pav or P .

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Resistance
16.97 V
V
12 V
Irms Vrms/R 12/5 2.4 A
Vo Vrms x v2 12 x v2 16.97 V

12 V (rms)
Io Vo/R 16.97/5 3.4 A
5 ?
R Vrms /Irms 12/2.4 5 ?
R Vo/Io 16.97/3.394 5 ?
Resistance can be worked out either way!

• Pav VRMSIRMS or P I2RMS R

34
Power Transmission
P ..............................................
P ...........................................
0.6 A
0.6 A
Cable resistance 200 km 10 ?
25 000V 0,6A
Cable resistance 200 km 10 ?
250 000V 0,06A
Voltage drop V Power lost
Voltage drop V Power lost

• Reducing the current ensures .....................
  .................in transmission.

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Power Transmission
P VI (25000)(0.6) 15 000 W
P VI (250000)(0.06) 15 000 W
0.6 A
0.6 A
Cable resistance 200 km 10 ?
25 000V 0,6A
Cable resistance 200 km 10 ?
250 000V 0,06A
Voltage drop V IR (0,048)(10) 0.48 V Power
lost VI (0.48)(10)
4.8 W
Voltage drop V IR (0,6)(10) 60 V Power
lost VI (60)(10)
600 W

• Reducing the current ensures less voltage/power
  lost in transmission.

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RECTIFIED CURRENT