FOWLER CHAPTER 8 LECTURE 8 ALTERNATING CURRENT AND VOLTAGE

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FOWLER CHAPTER 8LECTURE 8 ALTERNATING CURRENT
AND VOLTAGE
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CHAPTER 8 AC AND VOLTAGE P.201
FOR A DC WAVEFORM IN A SIMPLE CIRCUIT THE OUPUT
IS ALWAYS CONSTANT, EXCEPT WHEN THE CIRCUIT IS
SWITCHED ON/OFF. DC WAVEFORMS CAN BE OR - BUT
NEVER BOTH.
V

-
t
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TYPES OF AC WAVEFORMS
SINUSOIDAL
MOST COMMONLY USED IN DIGITAL ELECTRONICS
SAWTOOTH( TV,RADAR)
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CYCLE P.203 ONE WAVEFORM THAT DOES NOT REPEAT
ITSELF
½ CYCLE
.25 S
PERIOD (T) TIME TO COMPLETE ONE CYCLE.( IN THIS
CASE .25 SECONDS)
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SAME THING
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FREQUENCY( f ) OF CYCLES/SECOND
Time (sec) FOR THIS WAVEFORM f 1 CYCLES/SEC
HERTZ UNIT OF FREQUENCY . FOR THE ABOVE WAVEFORM
f 1 Hz
f 1/T OR f 1/?
AMPLITUDE (a) HEIGTH OF THE WAVEFORM.
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EXAMPLE FIND THE FREQUENCY FOR THE WAVE FORM
BELOW.
1/T 1/20ms 1/.002 500Hz
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PEAK VP MAX. VALUE OF WAVEFORM.
CAN BE EITHER OR-
SINCE WAVEFORMS ARE NOT CONTINIOUS AT ALL TIMES
THE AVERAGE VALUE IS USED. VAV AVERAGE
VALVE VAV 0.637VP VP 1.57VAV

USEFUL IN AC/DC CIRCUITS
M/U38 330-1240
http//www.youtube.com/watch?v7QCxbwzikFk
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RMS( ROOT-MEAN-SQUARE) WHAT IS THAT? 1. WAVE
FORM IS DIVIDED UP INTO SMALL INTERVALS.
2. EACH INTERVAL IS SQUARDED.
3. MEAN (AVERAGE) OF
SQUARED VALUE IS FOUND.
4. SQUARE ROOT OF THE MEAN IS CALCULATED. \
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RMS value is an equivalent DC value which tells
you how many volts or amps of DC that a
time-varying sinusoidal waveform is equal to in
terms of its ability to produce the same power.
For example, If you have mains supply of 240Vac
and is assumed an effective value of 240 Volts
RMS. This means then that the sinusoidal RMS
voltage from the wall sockets of a home is
capable of producing the same average positive
power as 240 volts of steady DC voltage as shown
below.
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rms voltage 0.707 peak voltage rms voltage 1.11 average voltage
peak voltage 1.414 rms voltage peak voltage 1.57 average voltage
average voltage 0.637 peak voltage average voltage 0.9 rms voltage

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SINE WAVES REVIEW WHEN A CONDUCTOR MOVES THRU
A MAGNETIC FLUX, A VOLAGE AND CURRENT ARE
INDUCTED IN THE CONDUCTOR.
THE AMOUNT OF INDUCED VOLTAGE IS A FUNCTION OF
THE AMOUNT OF FLUX CUT BY THE CONDUCTOR
Magnetic Induction in a Wire
http//www.youtube.com/watch?vP3kJd3MDeuklistUU
Oc3q8ChcDYyeyFROxLDhuw
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• AMOUNT OF FLUX CUT DEPENDS ON
• SPEED OF THE CONDUCTOR
• FLUX DENSITY
• ANGLE THAT CONDUCTOR CROSSES THE MAGNETIC FILED.
• SEE FIG. 8.8,P208

• DIRECTION OF INDUCTED CURRENT DEPENDS ON
• DIRECTION CONDUCTOR IS MOVING.
• POLARITY OF THE MAGNETIC FIELD.

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LEFT HAND RULE. P.209
http//www.youtube.com/watch?vKUrMt6ic53olistUU
Oc3q8ChcDYyeyFROxLDhuw
Building a Generator size of induced current
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PRODUCING SINE WAVES. P.209
YOU CAN GENERATING A SINE WAVE BY ROTATING A
CONDUCTOR THRU A MAGNETIC FIELD.
Commutators Basics on AC and DC Generation
http//www.youtube.com/watch?vATFqX2Cl3-wlistUU
Oc3q8ChcDYyeyFROxLDhuwindex6
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http//www.youtube.com/watch?vP83Qa3Chb7IlistUU
Oc3q8ChcDYyeyFROxLDhuw
Slip Rings and Brushes - Generators
ONE ROTATION OF A CONDUCTOR THRU 4 POLES
GENERATES TWO CYCLES OF VOLTAGE/CURRENT.
YOU TUBEAC Motor Animation Video
http//www.youtube.com/watch?vQ4FlUP-kJe8
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TO MAKE A AC GENERATOR YOU NEED THE
FOLLOWING PARTS WINDINGS,MULTILOOPED COIL.
ARMATURE WINDING WOUND ON A SILICON
STEEL CORE. SLIP RINGS
(COMMUTATORS) BRUSHES
FIELD COILS
YOU TUBE,How generator works by Khurram Tanvir
http//www.youtube.com/watch?vi-j-1j2gD28
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OUTPUT OF A GENERATOR DEPENDS ON 1. OF TURNS IN
THE ROTATING COILS. 2. SPEED THAT THE COILS
ROTATE. 3. FLUX DENSITY OF THE MAGNETIC FIELD.
YOU TUBEAC Generator Action.avi
http//www.youtube.com/watch?vmCvXa_VVFh4
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• GENERATOR FREQUENCY P.212
• FREQ. OUTPUT OF A GENERATOR DEPENDS ON
• OF PAIRS OF MAGNETIC POLES.
• ROTATIONAL SPEED OF THE COILS.

FREQ. GEN.OUT (R PER MINUTE)X(PAIRS OF
POLES)/60 EXAMPLEWHAT IS FREQ. OF 6 POLE
GENERATOR ROTATING AT 1200 RPM?
AC GENERATOR BUILT IN 1890
http//www.youtube.com/watch?vd_aTC0iKO68
YOU TUBE,Magnetism Motors and Generators START
AT 25SEC
The Frequency of an AC Generator
www.wisc-online.com/ViewObject.aspx?IDIAU14108
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Advantages of A.C. over D.C. / Why generation is
done in A.C.

1. AC CAN BE GENERATED AT HIGH VOLTAGES.
2. HV AC GENERATORS ARE SIMPLER AND CHEAPER THEN DC
   GENERATORS.
3. AC CAN BE STEPPED UP OR DOWN WITH TRANSFORMERS.

The Mechanical Universe - 38 - Alternating
Current,1700-2100 AC vs.DC
http//www.youtube.com/watch?v7QCxbwzikFk
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50Hz vs. 60Hz
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Utility Frequencies in Use in 1897 in North
America
Hz Description
140 Wood arc-lighting dynamo
133 Stanley-Kelly Company
125 General Electric single-phase
66.7 Stanley-Kelly company
62.5 General Electric "monocyclic"
60 Many manufacturers, becoming "increasingly common" in 1897
58.3 General Electric Lachine Rapids
40 General Electric
33 General Electric at Portland Oregon for rotary converters
27 Crocker-Wheeler for calcium carbide furnaces
25 Westinghouse Niagara Falls 2-phase - for operating motors
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Utility Frequencies in Europe to 1900
Cycles Description
133 Single-phase lighting systems, UK and Europe
125 Single-phase lighting system, UK and Europe
70 Single-phase lighting, Germany 1891
65.3 BBC Bellinzona
60 Single phase lighting, Germany, 1891, 1893
50 AEG, Oerlikon, and other manufacturers, eventual standard
48 BBC Kilwangen generating station,
46 Rome, Geneva 1900
45 1/3 Municipal power station, Frankfurt am Main, 1893
42 Ganz customers, also Germany 1898
41 2/3 Ganz Company, Hungary
40 Lauffen am Neckar, hydroelectric, 1891, to 1925
38.6 BBC Arlen
25 Single phase lighting, Germany 1897
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3 PHASE AC P.213 POWER PLANTS PRODUCE 3 PHASE AC.
EACH PHASE IS SEPARATED BY 120. P. 214
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http//www.youtube.com/watch?vfGPdPKMSpv8
3 Phase AC Motor Working Principle
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(b) Output waveform (red) for three cycles of a
200 Vp-p input to a single-phase half-wave
rectifier
(a) Output waveform (red) for three cycles of a
200 Vp-p input to a three-phase half-wave
rectifier
Fig. 8-24 P.220 A comparison of half-wave
rectification of single-phase and
three-phase ac.
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(a) Output waveform of a full-wave single-phase
rectifier with an input of 200 Vp-p.
(a) Output waveform of a full-wave three-phase
rectifier with an input of 200 Vp-p.
Fig. 8-25 P.221 Comparison of full-wave
rectification of three-phase and
single-phase ac.
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3 PHASES ARE CONNECTED SO THE LOAD CAN BE CARRIED
ON 3 CONDUCTORS FROM THE POWER PLANT TO THE
USER. 3 PHASES ARE CONNECTED IN EITHER DELTA OR
WYE CONFIGURATION.
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120/208 3-Phase Wye 208 volts are present
between all 3 phases. 120 volts between all 3
phases to Neutral
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3 PHASE 120/208V, 4 WIRE WYE SYSTEM
LINE 1
120 V
PHASE 1 120 V
208 V
NEUTRAL
TO 3 PHASE LOADS
PHASE 3 120 V
208 V
120 V
PHASE 2 120 V
LINE 2
GROUND
120 V
208 V
LINE 3
UNDER LOADLINE AND PHASE CURRENTS ARE NOT
EQUAL. SINCE 2 PHASE VOLTAGES ARE SEPARATED BY
120º , THEY CANNOT BE ADDED TOGETHER ILINE
1.732IPHASE VLINE 1.732VPHASE VLINE2
1.732(120V) 208V SINGLE PHASE 120 V ARE
CONNECTED BETWEEN THE NEUTRAL AND ANY ONE
LINE. SINGLE PHASE 208 V CIRCUITS ARE CONNECTED
BETWEEN ANY 2 OF THE 3 LINES. 3 PHASE 208 V ARE
CONNECTED ACROSS 3LINES.
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ADVANTAGES OF 3 PHASE (F) SYSTEMS. 1.MORE
EFFICENT USE OF COPPER. 2 PROVIDES A MORE
CONSTANT LOAD ON THE GENERATOR. 3. MOTORS ARE
LESS COMPLEX 4. 2 OUT OF 3 PHASES ARE PROVIDING
CURRENT AT ANY TIME.
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VARIOUS 3 PHASE TRANSFORMERS
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ELECTRIC CARS HYBRIDS AND PLUG IN HYBRIDS
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CHARGING A ELECTRIC CAR USING MAGNETIC INDUCTION
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INDUCTION COILS CHARGING A ELECTRIC CARS BATTERY
PACK
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ONE OF THE MANY PRESENT DAY PLUG AND SOCKET FOR
ELECTRIC CARS
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Leviton Evr-Green Base Level 1 GFCI Guide Light
Receptacle for Electric Vehicles
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Charging time Power supply Voltage Max current
68 hours Single phase - 3,3 kW 230 VAC 16 A
23 hours Three phase - 10 kW 400 VAC 16 A
34 hours Single phase - 7 kW 230 VAC 32 A
12 hours Three phase - 24 kW 400 VAC 32 A
2030 minutes Three phase - 43 kW 400 VAC 63 A
2030 minutes Direct current - 50 kW 400 - 500 VDC 100 - 125 A
Battery swapping
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The lithium-ion batteries can store up to 24kWh
of electricity, which is sufficient to supply an
average Japanese household for about two days.
This system underscores an additional attribute
of EVs vehicles which can be used as a storage
battery whether they are moving or stationary.
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Nissan Motor Co., Ltd. will launch the "LEAF to
Home" power supply system, which can supply
electricity from batteries onboard in Nissan LEAF
electric vehicles (EV) to homes when used with
the "EV Power Station" unit developed by Nichicon
Corporation. "LEAF to Home" is an industry first
backup power supply system that can transmit the
electricity stored in the large-capacity
batteries of Nissan LEAFs to a residential home.
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This system helps to balance the electrical
supply system, and can even lower a consumer's
electricity bill. The LEAF to Home system will
help encourage Nissan LEAF owners to charge their
cars with electricity generated during the night,
when demand is low, or sourced from solar panels.
This assist in balancing energy needs by
supplying electricity to the grid during daytime,
when demand is highest. It can also be used as
back-up power source in case of power outages
and/or shortages.
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