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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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 AnalysisLesson 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!