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Situation 2 Introduction to Port Electric Components

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Task1 Battery, Generator and Electric Motor I Why to learn? They are the major electric components commonly used in the electric equipments so it ... – PowerPoint PPT presentation

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Title: Situation 2 Introduction to Port Electric Components


1
Situation 2 Introduction to Port Electric
Components
2
Task1 Battery, Generator   and     Electric Motor
     
Task2 Programmable Logic Controller
Task3 Common Electric Components 
Lesson 18 Relay
Lesson 19 Low-voltage Switch
Lesson 20 Master Switch
Lesson 21 Frequency Converter 
Lesson 22 Contactor and Fuse
Lesson 23 Transformers
3
Task1 Battery, Generator   and     Electric Motor
   
  • I Why to learn?
  • They are the major electric components commonly
    used in the electric equipments so it is
    necessary to learn the structure and operation
    principle of them.

4
Task1 Battery, Generator   and     Electric Motor
 
  • II How to learn?
  • Seminar (??????????)
  • Organize the students in groups and provide with
    some tasks to complete including answering the
    questions and translating the corresponding
    paragraphs.
  • Lecture(?????)
  • III Content
  • lesson13Battery and Generator Lesson16 Electric
    Motor

5
Lesson 13 Battery and Generator
Lead-in
New Words
Text Analysis
Exercise
6
Lead-in
What is the function of battery and generator?
7
New Words
  • battery n. ??
  • generator n. ???
  • chemical energy ???
  • electric energy ??
  • wet- charged battery ??????
  • dry-charged battery ??????
  • low maintenance battery ??????
  • maintenance-free battery ??????

8
New Words
  • plate n. ??
  • separator n. ??
  • electrolyte n. ???
  • battery case ?????
  • negative terminal ???
  • dc generator ?????
  • ac generator ?????
  • mechanical energy ???
  • starter n. ???

9
New Words
  • rectify v. ??
  • silicon rectifying generator ??????
  • brush holder ???
  • gland n. ??
  • silicon diode ????
  • rectification component plate ?????
  • rotor assembly ????
  • stator assembly ????
  • fan n. ??
  • belt wheel disc ????

10
Text Analysis Lesson 2 Battery and Generator
  • Para1 On handling machinery in many ports,
    the electric energy needed by all electric
    equipments is supplied by the battery and the
    generator. The battery is a reversible chemical
    power source, that is to say, it can change
    chemical energy into electric energy and also it
    can change electric energy into chemical energy.
  • Para2 Generally speaking, the function of battery
    used on ICE in many ports is to supply electric
    current for operation of the cranking motor and
    the ignition system when the engine starts. It
    also supplies current for light, horn, radio, and
    other electrical accessories at times when the
    generator can not handle the electrical load. The
    amount of current of the battery is limited to
    the capacity of the battery. The capacity of
    battery depends on the amount of chemicals it
    contains.

11
  • Para3The common types of batteries used on
    handling machinery in port are wet- charged
    battery, dry-charged battery, low maintenance
    battery and maintenance-free battery. The
    connecting mode among generator, battery and the
    whole electrical equipments of the vehicle is
    parallel connection (see Fig2-1).

1-regulator 2-generator 3-electrical equipment 4-b
attery 5-ammeter 6-start button 7-starter  2-1 jun
ction circuit of power supply and load
12
  • Para4The main components of the battery are plate
    (positive plate and negative plate), separator,
    electrolyte and battery case. The structure of
    the common battery is shown in fig2-2.

1-battery case 2-battery cover  3-negative termina
l 4-charging plug  5-connection of simple lattice 
6-connection bar  7-negative plate 8-separator 9-p
ositive plate Fig 2-2 structure of
 battery
13
  • Para5The port internal combustion engines use
    both dc generator and ac generator. The dc
    generator is driven by ICE. It can change the
    mechanical energy into electric energy. During
    its working time, it can not only supply electric
    current to all the electric equipments except the
    starter, but also the battery.  In a general way,
    DC generators can be divided into two kinds
    separately excited generator (see fig 2-3) and
    self excited generator (see fig 2-4)

14
  • Fig 2-3 separately excited generator

Fig 2-4 self excited generator
15
  • Para6 In recent years, alternating-current
    (a-c) generators have come into widespread use.
    But the battery, ignition system, and other
    electrical components can not use a-c because
    they are all d-c units. So the a-c output must
    therefore be rectified, or changed to d-c.
    Customarily, ac generator is also called silicon
    rectifying generator (see fig2-5).

16
Fig 2-5 Silicon Rectifying Generator
1-rear cover 2-brush holder 3-brush 4-gland  5-sil
icon diode 6-rectification component plate  7-roto
r assembly 8-stator assembly  9-front end cover 10
-fan 11-belt wheel disc
17
Para1
  • Q What is battery?
  • KeyThe battery is a reversible chemical power
    source, that is to say, it can change chemical
    energy into electric energy and also it can
    change electric energy into chemical energy.

18
Para2
  • Q What is the function of battery?
  • KeyGenerally speaking, the function of battery
    used on ICE in many ports is to supply electric
    current for operation of the cranking motor and
    the ignition system when the engine starts. It
    also supplies current for light, horn, radio, and
    other electrical accessories at times when the
    generator can not handle the electrical load.
  • Cn
  • ??????????????????????????????????????????????????
    ????????????????????????????

19
Para3
  • Q1 Name common types of batteries used on
    handling machinery in port.
  • Key The common types of batteries used on
    handling machinery in port are wet- charged
    battery, dry-charged battery, low maintenance
    battery and maintenance-free battery.
  • Q2 What is the connecting mode used among
    generator battery and the whole electrical
    equipments of the vehicle?
  • Key
  • The connecting mode among generator, battery and
    the whole electrical equipments of the vehicle is
    parallel connection

20
Para4
  • Q What are the main components of the battery?
  • Key The main components of the battery are plate
    (positive plate and negative plate), separator,
    electrolyte and battery case.
  • Cn
  • ??????????(?????????)??????????????

21
Para5
  • Q 1What is the function of DC generator?
  • KeyIt can change the mechanical energy into
    electric energy. During its working time, it can
    not only supply electric current to all the
    electric equipments except the starter, but also
    the battery.
  • Q2 What are the two kinds of DC generators?
  • Key In a general way, DC generators can be
    divided into two kinds separately excited
    generator and self excited generator .

22
Para6
  • Q1 Can the battery use AC ? If not how to solve
    the problem?
  • KeyThe battery,can not use a-c because it is d-c
    unit. So the a-c output must therefore be
    rectified, or changed to d-c.

23
Exercises
Words Matching
Translation
24
Words Matching
  • wet- charged battery ????? ??
  • dry-charged battery
    ??????
  • low maintenance battery ???
  • maintenance-free battery
    ??????
  • plate n. ??
  • separator n. ???
  • electrolyte n.
  • battery case
    ??????
  • negative terminal ??????

25
Translation
  • During its working time, it can not only supply
    electric current to all the electric equipments
    except the starter, but also the battery.
  • Key????????????????????????????????????????

26
Lesson 16 Electric Motor
Lead-in
New Words
Text Analysis
Exercises
27
Lead-in
  • What is the function of electric motor?

28
New Words1
  • electric motor ???
  • mechanical movement ????
  • DC motor ?????
  • AC motor ?????
  • armature n. ??
  • main pole ???
  • brush holder ??
  • commutator n. ???
  • commutation pole ????
  • alternate v. ??

29
New Words2
  • frequency n. ??
  • alternating current ??
  • asynchronous motor ?????
  • maintenance n. ??,??
  • single-phase asynchronous motor ???????
  • three-phase asynchronous motor ???????
  • stator core ????
  • stator winding ????
  • rotor n. ??
  • frame n. ??
  • enclosure n. ??

30
Text Analysis Lesson 5 Electric Motor
  • Para1 Electric motors are everywhere! In your
    house, in your work place almost every mechanical
    movement you can find an AC (alternating current)
    or DC (direct current) electric motor.
  • Para2 Firstly lets look at dc motors. DC motors
    (see fig 5-1) are easy to understand. They are
    also simple to make and only require a battery or
    dc supply to make them run. A simple motor
    consists of six parts armature or rotor,
    commutator, brushes, axle, field magnet and DC
    power supply of some sort.

31
Fig 5-1
1-fan 2-motor base 3- armature 4-main pole 5-
brush holder 6- commutator 7- wiring board 8-
outlet box 9- commutation pole 10- end cover
32
  • Para3 Secondly, lets learn something about ac
    motor. If we apply alternating current to the
    simple direct current motor, the obstacle of how
    to reverse the current and the polarity of the
    electromagnet are no longer an issue. Since the
    current alternates direction at a certain
    frequency, the magnetic field of an electromagnet
    can be made to change polarity at the same
    frequency.
  • Para4 If the same device is put to use in
    reverse, that is, if an outside mechanical force
    is used to turn the armature, an alternating
    current will be produced illustrated in fig5-2

33
Fig5-2
34
  • Para5 Among the ac motors, asynchronous motors
    are the most popular in port. Because they have
    the following advantages simple structure, easy
    maintenance and operation, low price, reliable
    operation and so on. If we divide the
    asynchronous motors from the angle of power
    supply, we can get single-phase asynchronous
    motor and three-phase asynchronous motor (see
    fig5-3).

35
Fig5-3 Three-phase Asynchronous Motor
1- bearing cap 2- end cover 3- terminal box 4-
stator core 5- stator winding 6- rotating shaft
7- rotor 8-fan 9-frame 10- bearing 11- enclosure
36
Para2
  • Q What are the components of a simple motor?
  • Key A simple motor consists of six parts
    armature or rotor, commutator, brushes, axle,
    field magnet and DC power supply of some sort.

37
Para3
  • Q W hat is the function of AC current in the
    motor?
  • KeyIf we apply alternating current to the simple
    direct current motor, the obstacle of how to
    reverse the current and the polarity of the
    electromagnet are no longer an issue. Since the
    current alternates direction at a certain
    frequency, the magnetic field of an electromagnet
    can be made to change polarity at the same
    frequency.

38
Para5
  • Q1 Why asynchronous motors are the most popular
    in port.
  • Key Because they have the following advantages
    simple structure, easy maintenance and operation,
    low price, reliable operation and so on.
  • Q2 What are the two kinds of asynchronous motors?
  • Key If we divide the asynchronous motors from
    the angle of power supply, we can get
    single-phase asynchronous motor and three-phase
    asynchronous motor

39
Exercises
Words Matching
Translation
40
Words Matching
  • frequency n. ??
  • alternating current
    ??,??
  • asynchronous motor ???
  • maintenance n. ????
  • single-phase asynchronous motor
    ????
  • stator core ??
    ??
  • stator winding
    ?????
  • rotor n.
    ???????
  • frame n. ??
  • enclosure n.

41
Translation
  • If we apply alternating current to the simple
    direct current motor, the obstacle of how to
    reverse the current and the polarity of the
    electromagnet are no longer an issue. Since the
    current alternates direction at a certain
    frequency, the magnetic field of an electromagnet
    can be made to change polarity at the same
    frequency.
  • Key
  • ?????????????????,????????????????????????????????
    ???????????????????????

42
Task2 Programmable Logic Controller    
  • I Why to learn?
  • PLC is an electric equipment usually used for
    controlling the operation of some machines so it
    is necessary to learn the structure and operation
    principle of it.

43
Task2 Programmable Logic Controller
  • II How to learn?
  • Seminar (??????????)
  • Organize the students in groups and provide with
    some tasks to complete including answering the
    questions and translating the corresponding
    paragraphs.
  • Lecture(?????)
  • III Content
  • Lesson17 Programmable Logic Controller

44
Lesson 17 Programmable Logic Controller
Lead-in
New Words
Text Analysis
Exercises
45
Lead-in
  • Q What is programmable logic controller ?

46
New Words1
  • programmable logic controller ??????
  • definition n. ??
  • input n. ??
  • output n. ??
  • logic adj. ???
  • electromechanical adj. ???
  • interpret v. ??,??
  • output terminal ???
  • program v. ??

47
New Words2
  • ladder logic diagram ???
  • programmer n. ???
  • cassette magnetic tape unit
    ?????
  • EPROM writing device
    EPROM???
  • host computer ?????
  • input signal ????
  • host n. ??
  • central processing unit
    ?????
  • peripheral interface ????
  • RAM user program RAM????
  • I/O extended port I/O???
  • output signal ????

48
Text Analysis Lesson 6 Programmable Logic
Controller
  • Para1 In practice, we often use PLC to stand for
    programmable logic controller. Can you give the
    definition of PLC? Maybe we can define it just
    like this A programmable logic controller (PLC)
    is a digital computer used for automation of
    industrial processes, such as control of
    machinery on factory assembly lines.
  • Para2 Unlike general-purpose computers, the PLC
    is often designed for multiple inputs and output
    terminals, extended temperature ranges, immunity
    to electrical noise, and resistance to vibration
    and impact. The purpose of a PLC was to directly
    replace electromechanical relays as logic
    elements, substituting a solid-state digital
    computer with a stored program. Fig6-1 is the
    structure block diagram of integral PLC.

49
Fig6-1
1- programmer 2- cassette magnetic tape unit 3-
printer 4-EPROM writing device 5-PLC or host
computer 6- input signal 7-input unit 8-host
9-power supply 10-central processing unit (CPU)
11-peripheral interface 12-EPROM system program
13-RAM user program 14- I/O extended port
15-output unit 16- I/O extended unit 17- output
signal
50
  • Para3 From fig6-1, we can see A PLC has many
    "input" terminals, through which it interprets
    "high" and "low" logical states from sensors and
    switches. It also has many output terminals,
    through which it outputs "high" and "low" signals
    to power lights, solenoids, contactors, small
    motors, and other devices lending themselves to
    on/off control.
  • Para4 In order to make PLCs easy to program,
    their programming language was designed to
    resemble ladder logic diagrams. Thus, an
    industrial electrician or electrical engineer
    would feel comfortable programming a PLC, because
    they are accustomed to reading ladder logic
    schematics.

51
  • Para5The actual logic of the control system is
    established inside the PLC by a computer program.
    This program dictates which output gets energized
    under which input conditions. Although the
    program appears to be a ladder logic diagram,
    with switch and relay symbols, there are no
    actual switch contacts or relay coils operating
    inside the PLC to create the logical
    relationships between input and output. They are
    imaginary contacts and coils. In fact, the
    program is entered and viewed via a personal
    computer connected to the PLC's programming port.

52
Para1
  • Q Can you give the definition of PLC?
  • Key A programmable logic controller (PLC) is a
    digital computer used for automation of
    industrial processes, such as control of
    machinery on factory assembly lines.

53
Para2
  • Q1 What is the difference between PLC and
    general-purpose computers
  • Key
  • Unlike general-purpose computers, the PLC is
    often designed for multiple inputs and output
    terminals, extended temperature ranges, immunity
    to electrical noise, and resistance to vibration
    and impact.
  • Q2 What is the function of PLC?
  • KeyThe purpose of a PLC was to directly replace
    electromechanical relays as logic elements,
    substituting a solid-state digital computer with
    a stored program.

54
Para3
  • Q How does PLC work?
  • Key A PLC has many "input" terminals, through
    which it interprets "high" and "low" logical
    states from sensors and switches. It also has
    many output terminals, through which it outputs
    "high" and "low" signals to power lights,
    solenoids, contactors, small motors, and other
    devices lending themselves to on/off control.
  • Cn
  • ????????????,?????,???????????????????????????
    ???,?????,?????? ???????????????????????/?????
    ???

55
Para4
  • Q What are the characteristics of PLCprogramming
    language? Why?
  • Key Their programming language was designed to
    resemble ladder logic diagrams. Thus, an
    industrial electrician or electrical engineer
    would feel comfortable programming a PLC, because
    they are accustomed to reading ladder logic
    schematics.

56
Para5
  • Are the switch contacts and relay coils in the
    program real?
  • Key Although the program appears to be a ladder
    logic diagram, with switch and relay symbols,
    there are no actual switch contacts or relay
    coils operating inside the PLC to create the
    logical relationships between input and output.
    They are imaginary contacts and coils.

57
Exercises
Words Matching
Translation
58
Words Matching
  • ladder logic diagram
    EPROM???
  • programmer n. I/O???
    ???
  • cassette magnetic tape unit
    RAM????
  • EPROM writing device
    ????
  • host computer ?????
  • host n. ????
  • central processing unit
  • peripheral interface
    ??
  • RAM user program
  • I/O extended port
    ??? ?????
  • output signal ?????

59
Translation
  • Although the program appears to be a ladder
    logic diagram, with switch and relay symbols,
    there are no actual switch contacts or relay
    coils operating inside the PLC to create the
    logical relationships between input and output.
    They are imaginary contacts and coils.
  • Key ??????????????????????,???PLC
    ??????????????????????????????????????????????

60
Task3 Common Electric Components    
  • I Why to learn?
  • They are major parts used frequently in electric
    equipments and facilities so it is necessary to
    learn the structure and functions of them.

61
Task2 Programmable Logic Controller
  • II How to learn?
  • Seminar (??????????)
  • Organize the students in groups and provide with
    some tasks to complete including answering the
    questions and translating the corresponding
    paragraphs.
  • Lecture(?????)
  • III Content
  • Lesson 18 Relay
  • Lessson 19 Low-voltage Switch
  • Lesson 20 Master Switch
  • Lesson 21 Frequency Converter
  • Lesson 22 Contactor and Fuse
  • Lesson 23 Transformers

62
Lesson 18 Relay
Lead-in
New Words
Text Analysis
Exercises
63
Lead-in
  • Q What is a relay?

64
New Words1
  • relay n. ???
  • electrical switch ????
  • electromagnet n. ???
  • circuit symbol ????
  • electromagnetic relay ?????
  • voltage relay ?????

65
New Words2
  • current relay ?????
  • auxiliary relay ?????
  • thermal relay ????
  • time relay ?????
  • velocity relay ?????
  • symbol n. ??,??

66
Text Analysis Lesson 18 Relay
  • Para1 What is a relay? In a general way, a relay
    is an electrical switch that opens and closes
    under the control of another electrical circuit.
    In the original form, the switch is operated by
    an electromagnet to open or close one or many
    sets of contacts. Because a relay can control an
    output circuit of higher power than the input
    circuit, it can be considered to be a form of an
    electrical amplifier.
  • Para2 The circuit symbol for a relay and the
    pictures of the common relays are presented in
    fig7-1. Fig 7-2 shows a working relay with its
    coil and switch contacts.

67
Fig 7-1 Relays
Circuit symbol for a relay    
68
Fig 7-2
69
  • Para3The most common relays used on port
    machinery are electromagnetic relay (which
    includes voltage relay, current relay and
    auxiliary relay), thermal relay, time relay and
    velocity relay.
  • Para4The symbols of the common relays are shown
    in fig 7-3.

70

Fig 7-3
symbol of thermal relay
symbol of electromagnetic relay
symbol of velocity relay
symbol of time relay
71
Para1
  • Q What is a relay?
  • KeyIn a general way, a relay is an electrical
    switch that opens and closes under the control of
    another electrical circuit.

72
Para2
  • Q What do NO,COM and NC stand for?
  • Key NO, Normal open contact
  • NC, Normal close contact
  • COM,

73
Para3
  • Q What are the most common relays used on port
    machinery?
  • Key The most common relays used on port
    machinery are electromagnetic relay (which
    includes voltage relay, current relay and
    auxiliary relay), thermal relay, time relay and
    velocity relay.

74
Exercises
Words Matching
Translation
75
Words Matching
  • current relay ?????
  • auxiliary relay ?????
  • thermal relay ????
  • time relay ?????
  • velocity relay ?????
  • electromagnetic relay ?????
  • voltage relay ?????

76
Translation
  • In the original form, the switch is operated by
    an electromagnet to open or close one or many
    sets of contacts. Because a relay can control an
    output circuit of higher power than the input
    circuit, it can be considered to be a form of an
    electrical amplifier.
  • Key ?????,???????????????????????????????????????
    ???????,???????????????????

77
Lesson 19Low-voltage Switch
Lead-in
New Words
Text Analysis
Exercises
78
Lead-in
  • Q What is low-voltage switch?

79
New Words
  • low-voltage switch ????
  • knife switch ???
  • transfer switch ????
  • automatic switch ????
  • application n. ??
  • combination switch ????
  • manual adj. ???
  • automatic air switch ??????
  • automatic air-blast breaker ???????

80
Text Analysis Lesson 19 Low-voltage Switch
  • Para1 Low-voltage switch here refers to knife
    switch, transfer switch and automatic switch. The
    picture of knife switch is shown in fig8-1.And
    its symbol is just like fig 8-2. Today, the use
    of knife switches has been confined to heavy-duty
    industrial applications and to demonstration
    purposes. The knife switch has a metal lever,
    insulated at the 'free end' that comes into
    contact with a metal 'slot'. Since the electrical
    connections are exposed, knife switches are never
    seen in household wiring.

81
Fig 8-1 Fig 8-2 Symbol of Knife Switch
Fig 8-2 symbol of knife switch
Fig 8-1
82
  • Para2 Transfer switch is also called combination
    switch (see fig 8-3). Its symbol is shown as fig
    8-4. Most often transfer switches can be seen
    where emergency power generators are used to back
    up power. The switch is a manual switch, an
    automatic switch or a combination of manual and
    automatic.

Fig 8-3 combination switch 
83
Fig 8-4
84
  • Para3 Another name of automatic switch is
    automatic air switch or automatic air-blast
    breaker. Fig 8-5 shows an automatic air switch.
    And fig 8-6 shows the symbol of a common
    automatic switch.

85
Fig 8-5 Fig 8-6
Fig 8-6
Fig 8-5
86
Para1
  • Q1 What is low-voltage switch?
  • KeyLow-voltage switch here refers to knife
    switch, transfer switch and automatic switch.
  • Q2 On what occasions are knife switch often used?
  • Key The use of knife switches has been confined
    to heavy-duty industrial applications and to
    demonstration purposes.
  • Q2 Why knife switches are never seen in household
    wiring?
  • Key The knife switch has a metal lever,
    insulated at the 'free end' that comes into
    contact with a metal 'slot'. Since the electrical
    connections are exposed, knife switches are never
    seen in household wiring.

87
Para2
  • Q On what occasions are knife switch often used?
  • KeyMost often transfer switches can be seen
    where emergency power generators are used to back
    up power.

88
Para3
  • Q What is another name of automatic switch?
  • Key Another name of automatic switch is
    automatic air switch or automatic air-blast
    breaker.

89
Exercises
Words Matching
Translation
90
Words Matching
  • low-voltage switch ??????
  • knife switch ????
  • transfer switch ???????
  • automatic switch ????
  • combination switch ????
  • manual adj. ????
  • automatic air switch ???
  • automatic air-blast breaker
    ???

91
Translation
  • Most often transfer switches can be seen where
    emergency power generators are used to back up
    power.
  • Key?????????????????????????

92
Lesson 20 Master Switch
Lead-in
New Words
Text Analysis
Exercises
93
Lead-in
  • Q What is a master switch?
  • KeyA master switch is an electrical apparatus
    used to send out signal instruction in electric
    automatic control system.

94
New Words1
  • master switch ????
  • electrical apparatus ????
  • button n. ??
  • travel switch ????
  • proximity switch ????
  • universal change switch ??????
  • master controller ?????
  • intervention n. ??
  • normal open contact ????

95
New Words2
  • normal close contact ????
  • composite contact ????
  • limit switch ????
  • position switch ????
  • button type ???
  • rotary type ???
  • no-contact travel switch ???????
  • shift n. ??
  • fixed contact ????
  • moving contact ???

96
Text Analysis Lesson 9 Master Switch
  • Para1 A master switch is an electrical apparatus
    used to send out signal instruction in electric
    automatic control system. Common master switch
    consists of button, travel switch, proximity
    switch, universal change switch and master
    controller.
  • Para2The picture of common button is shown in fig
    9-1.The most common button types are LA2, LA18,
    LA19 and LA20. Fig 9-2 shows symbols of some
    kinds of buttons. It is known that red stands for
    stop, green stands for start and yellow for
    intervention.

97
Fig 9-1 LA19 button
98
Fig 9-2
(a) normal open contact (b) normal close
contact (c) composite contact
99
  • Para3Travel switch is also called as limit switch
    or position switch. Travel switches have many
    types which are shown in fig 9-3.The symbols of
    some common travel switches are shown in fig 9-4.

(a) button type  (b) (c) rotary type Fig 9-3
100
Fig 9-4
(a) normal open contact  (b) normal close contact 
 (c) composite contact
101
  • Para4 Proximity switch (see fig 9-5) is also
    called no-contact travel switch.

Fig 9-5
102
  • Para5 Universal change switches have more shifts,
    contacts and more control circuits, so we call it
    universal. LW5 universal change switch is
    presented in fig9-6.

Fig 9-6 LW5 universal change switch
103
  • Para6 A master controller is a kind of master
    switch which switches several control circuits
    frequently. The structure schematic diagram of
    the master controller refers to fig 9-7.

Fig 9-7
104
Para1
  • Q1 What is a master switch?
  • KeyA master switch is an electrical apparatus
    used to send out signal instruction in electric
    automatic control system.
  • Q2 What are the components of a master switch?
  • Key Common master switch consists of button,
    travel switch, proximity switch, universal change
    switch and master controller.

105
Para2
  • Q What are the most common button types?
  • Key The most common button types are LA2, LA18,
    LA19 and LA20.

106
Para3
  • Q What are other names of the travel switch?
  • KeyTravel switch is also called as limit switch
    or position switch.

107
Para4
  • Q What is Proximity switch also called ?
  • Key Proximity switch is also called no-contact
    travel switch.

108
Para5
  • Q How does the universal change swithch get the
    name?
  • KeyUniversal change switches have more shifts,
    contacts and more control circuits, so we call it
    universal.

109
Para6
  • Q What is master controller?
  • Key A master controller is a kind of master
    switch which switches several control circuits
    frequently.

110
Exercises
Words Matching
Translation
111
Words Matching
  • master controller ??
  • intervention n. ???? ?????
  • normal open contact ????
  • normal close contact ???
  • composite contact ???
  • limit switch ????
  • position switch ????
  • button type
  • rotary type ????

112
Translation
  • A master controller is a kind of master switch
    which switches several control circuits
    frequently.
  • Cn
  • ??????????????????????????

113
Lesson 21 Frequency Converter
Lead-in
New Words
Text Analysis
Exercises
114
Lead-in
  • Q1 What is the function of frequency converter?
  • KeyThe frequency converter can
    convertalternating current (AC) of one frequency
    to alternating current of another frequency. The
    device may also change the voltage.

115
New Words
  • frequency converter ???
  • frequency n. ??
  • voltage n. ??
  • voltage frequency converter ??????
  • current frequency converter ??????
  • pulse amplitude modulation ??????
  • pulse width modulation ????
  • phase n. ??

116
Text Analysis Lesson 21 Frequency Converter
  • Para1 A frequency converter or frequency changer
    (see fig10-1) is an electronic device that
    converts alternating current (AC) of one
    frequency to alternating current of another
    frequency. The device may also change the voltage.

Fig 10-1 TEMCO Frequency Converter
117
  • Para2 Frequency changers are often used to
    control the speed of pumps and fans. In many
    applications significant energy savings are
    achieved. The most demanding application areas
    are found on the industrial processing lines,
    where the control accuracy requirements can be
    very high.
  • Para3 Frequency converters have many
    classification methods
  • i) According to different operating patterns of
    the main circuits, frequency converters are
    divided into voltage frequency converters and
    current frequency converters.

118
  • ii) According to different switching modes,
    they can be classified as PAM frequency
    converter, PWM frequency converter and so on.
    Here PAM means pulse amplitude modulation, PWM
    means pulse width modulation.
  • iii) According to different working principle,
    we can define frequency converters them as V/f
    frequency converter, slip frequency converter and
    vector control frequency converter.
  • iv) According to different applications, we can
    classify converters into general inverter, high
    performance specific inverter, high frequency
    inverter and single phase inverter.

119
  • Para4 Common frequency converter configurations
    include
  • 50Hz or 60 Hz input
  • 50Hz or 60 Hz, or 400 Hz output
  • 120 volts through 600 volts input
  • 120 volts through 600 volts output
  • 1 or 3 phase input
  • 1 or 3 phase output
  • 6 kW through 200 kW

120
Para1
  • Q What is frequency converter?
  • keyA frequency converter or frequency changer
    (see fig10-1) is an electronic device that
    converts alternating current (AC) of one
    frequency to alternating current of another
    frequency. The device may also change the voltage.

121
Para2
  • Q1 Where are frequency changers often used?
  • Key Frequency changers are often used to control
    the speed of pumps and fans.
  • Q2 Why the industrial processing lines are the
    most demanding application areasfor the frequency
    changers?
  • Key The most demanding application areas are
    found on the industrial processing lines, where
    the control accuracy requirements can be very
    high.

122
Para3
  • Q How many types can frequency converters be
    classified into according to different methods?
  • Key1.According to different operating patterns
    of the main circuits, frequency converters are
    divided into voltage frequency converters and
    current frequency converters.
  • 2.According to different switching modes, they
    can be classified as PAM frequency converter, PWM
    frequency converter and so on. Here PAM means
    pulse amplitude modulation, PWM means pulse width
    modulation.
  • 3.According to different working principle, we
    can define frequency converters as V/f frequency
    converter, slip frequency converter and vector
    control frequency converter.
  • 4.According to different applications, we can
    classify converters into general inverter, high
    performance specific inverter, high frequency
    inverter and single phase inverter.

123
Para4
  • Q What are configurations of the common frequency
    converter?
  • Key Common frequency converter configurations
    include
  • 50Hz or 60 Hz input
  • 50Hz or 60 Hz, or 400 Hz output
  • 120 volts through 600 volts input
  • 120 volts through 600 volts output
  • 1 or 3 phase input
  • 1 or 3 phase output
  • 6 kW through 200 kW

124
Exercises
Words Matching
Translation
125
Words Matching
  • frequency converter ??????
  • frequency n. ??????
  • voltage n. ??
  • voltage frequency converter ????
  • current frequency converter ??
  • pulse amplitude modulation ??
  • pulse width modulation ???
  • phase n. ??????

126
Translation
  • According to different switching modes, they can
    be classified as PAM frequency converter, PWM
    frequency converter and so on. Here PAM means
    pulse amplitude modulation, PWM means pulse width
    modulation.
  • Cn
  • ?????????,???????PAM???,PWM?????
    PAM???????,PWM??????

127
Lesson 22 Contactor and Fuse
Lead-in
New Words
Text Analysis
Exercises
128
Lead-in
  • Q What is contactor and fuse?

129
New Words
  • contactor n. ???
  • fuse n. ???
  • amp n. ??
  • volt n. ??
  • contact system ????
  • electromagnet system ????
  • protective adj. ???
  • short circuit protection ????

130
Text Analysis Lesson 22 Contactor and Fuse
  • Para1 This passage mainly deals with contactor
    and fuse.
  • Contactor
  • Para2 Firstly, lets learn the contactor. A
    contactor (see fig 11-1) is an electrically
    controlled switch used for switching a power
    circuit. Generally speaking, a contactor is
    activated by a control input which is a lower
    voltage / current than that which the contactor
    is switching. Contactors come in many forms with
    varying capacities and features.

131
Fig 11-1
132
  • Para3 Contactors vary from having a breaking
    current of several amps and 110 volts to
    thousands of amps and many kilo-volts. The
    physical size of contactors differs from a few
    inches to the size of a small car.
  • Para4 Then lets know the purpose of contactor.
    Usually, contactors are used to control electric
    motors, lighting, heating, capacitor banks and
    other electrical loads.
  • Para5 And now lets see what a contractor
    consists of. We can say a contactor consists of
    3 different systems contact system,
    electromagnet system and arc control system.

133
  • Para6 So do you know their function? In a general
    way, the contact system is the current carrying
    part of the contactor. This includes power
    contacts, auxiliary contacts, and contact
    springs. The electromagnet system provides the
    driving force to close the contacts.
  • Fuse
  • Para7 Maybe you have already known that a fuse
    (see fig 11-2) is the easiest and efficient
    protective electrical apparatus and it is
    designed for short circuit protection in many
    cases. Always we use FU to stand for fuse.

134
Fig 11-2
135
Para1
  • Q What is the lesson mainly about?
  • KeyThis passage mainly deals with contactor and
    fuse.

136
Para2
  • Q What is a contactor?
  • Key A contactor is an electrically controlled
    switch used for switching a power circuit.

137
Para3
  • Translate the paragraph
  • Contactors vary from having a breaking current of
    several amps and 110 volts to thousands of amps
    and many kilo-volts. The physical size of
    contactors differs from a few inches to the size
    of a small car.
  • Cn
  • ?????????????????????,??????110?????????????????
    ????????????????

138
Para4
  • Q What is the purpose of contactor?
  • Key Usually, contactors are used to control
    electric motors, lighting, heating, capacitor
    banks and other electrical loads.

139
Para5
  • Q What does a contractor consist of?
  • Key A contactor consists of 3 different systems
    contact system, electromagnet system and arc
    control system.

140
Para6
  • Q What are the functions of contact system and
    electromagnet system?
  • Key In a general way, the contact system is the
    current carrying part of the contactor. This
    includes power contacts, auxiliary contacts, and
    contact springs. The electromagnet system
    provides the driving force to close the contacts.

141
Para7
  • Q What is a fuse?
  • Key A fuse is the easiest and efficient
    protective electrical apparatus and it is
    designed for short circuit protection in many
    cases.

142
Exercises
Words Matching
Translation
143
Words Matching
  • contactor n. ???
  • fuse n. ??
  • amp n. ???
  • volt n. ????
  • contact system ????
  • electromagnet system ????
  • protective adj. ???
  • short circuit protection ??

144
Translation
  • In a general way, the contact system is the
    current carrying part of the contactor. This
    includes power contacts, auxiliary contacts, and
    contact springs. The electromagnet system
    provides the driving force to close the contacts.
  • Cn
  • ??????????????????????????????????????????????????
    ??????

145
Lesson 23 Transformers
Lead-in
New Words
Text Analysis
Exercises
146
Lead-in
  • Q What is transformer and what is the function of
    it?

147
New Words
  • transformer n. ???
  • electrical energy ??
  • primary coil ????
  • secondary coil ????
  • electrical connection ????
  • induction n. ??
  • work efficiency ????

148
Text Analysis Lesson 23 Transformers
  • Para1 Have you ever seen the picture of fig12-1?
    Yes, it is a transformer. Maybe you often use a
    transformer in your daily life. So you must be
    familiar with it. We can define a transformer
    like this A transformer is a device that
    transfers electrical energy from one circuit to
    another circuit through inductively coupled
    electrical conductors. All transformers have at
    least one coil most have two although they may
    have many more. The usual function of
    transformers is to change the level of voltage.

149
Fig 12-1 Three-phase pole-mounted step-down
transformer
150
  • Para2 In fact, standard power transformers have
    two coils. These 2 coils are labeled PRIMARY and
    SECONDARY separately. And the primary coil is the
    one connected to the source. The secondary is the
    one connected to the load. You must notice there
    is no electrical connection between the primary
    and secondary. Actually, the secondary gets its
    voltage by induction.
  • Para3 Transformers come in a range of sizes from
    a thumbnail-sized coupling transformer which is
    hidden inside a stage microphone to huge units
    weighing hundreds of tons which is often used to
    interconnect portions of national power grids.
    But all operate with the same basic principles.
    Fig 12-2 tells us clearly the structure of a
    transformer. Have you got the working principle
    of it? Please think over.

151
Fig 12-2
152
  • Para4 At last lets pay attention to their
    working efficiency .It is said that transformers
    are some of the most efficient electrical
    machines, with some large units able to transfer
    99.75 of their input power to their output.

153
Para1
  • Q1 What is a transformer?
  • Key We can define a transformer like this A
    transformer is a device that transfers electrical
    energy from one circuit to another circuit
    through inductively coupled electrical
    conductors.
  • Q2 What is the function of it?
  • Key The usual function of transformers is to
    change the level of voltage.

154
Para2
  • Q What are the characteristics of the two coils
    in a standard power transformer?
  • KeyThese 2 coils are labeled PRIMARY and
    SECONDARY separately. And the primary coil is the
    one connected to the source. The secondary is the
    one connected to the load. You must notice there
    is no electrical connection between the primary
    and secondary. Actually, the secondary gets its
    voltage by induction.

155
Para3
  • Q How big is a transformer?
  • KeyTransformers come in a range of sizes from a
    thumbnail-sized coupling transformer which is
    hidden inside a stage microphone to huge units
    weighing hundreds of tons which is often used to
    interconnect portions of national power grids.

156
Para4
  • Q How efficient is a transformer?
  • KeyIt is said that transformers are some of the
    most efficient electrical machines, with some
    large units able to transfer 99.75 of their
    input power to their output.

157
Exercises
Words Matching
Translation
158
Words Matching
  • transformer n. ??
  • electrical energy
    ????
  • primary coil ????
  • secondary coil ????
  • electrical connection ???
  • induction n. ??
  • work efficiency ????

159
Translation
  • Transformers come in a range of sizes from a
    thumbnail-sized coupling transformer which is
    hidden inside a stage microphone to huge units
    weighing hundreds of tons which is often used to
    interconnect portions of national power grids.
  • Cn
  • ??????????,??????????????????????????,????????????
    ???????????

160
  • Thank you for your attention!
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