电气技术专业英语电气技术专业英语

朱一纶 主编朱一纶 主编

中国电力出版社中国电力出版社

Unit 9 Motor Controller Unit 9 Motor Controller

课件制作课件制作 : : 吴岱曦吴岱曦

IndexIndex

• TextText– 1. Introduction 1. Introduction – 2. Relay2. Relay– 3. Contactor3. Contactor

• Reading materialsReading materials– 1. Time Relay 1. Time Relay – 2. Novel controller 2. Novel controller – 3. Experiment material3. Experiment material

• ExercisesExercises– 1. Put the Phrases into English 1. Put the Phrases into English – 2. Put the Phrases into Chinese 2. Put the Phrases into Chinese – 3. Sentence Translation3. Sentence Translation– 4. 4. TranslationTranslation

TextText

1. Introduction1. Introduction

• A motor controller is a device or A motor controller is a device or group of devices that serves to group of devices that serves to govern in some predetermined govern in some predetermined manner the performance of manner the performance of an electrian electric motor. c motor.

• A motor controller might include a manA motor controller might include a manual or automatic means for starting and ual or automatic means for starting and stopping the motor, selecting forwardstopping the motor, selecting forward or reverse rotation, selecting and or reverse rotation, selecting and regulating the speed, regulating or regulating the speed, regulating or limiting the torque, and protecting limiting the torque, and protecting against overloads and faults. against overloads and faults.

• A motor controller is connected to a A motor controller is connected to a power source such as a battery pack power source such as a battery pack or power supply, and control circuitry or power supply, and control circuitry in the form of analog or digital input in the form of analog or digital input signals. signals.

• An electric current through a An electric current through a conductor will produce a magnetic conductor will produce a magnetic field at right angles to the direction field at right angles to the direction of electron flow. If that conductor is of electron flow. If that conductor is wrapped into a coil shape, the wrapped into a coil shape, the magnetic field produced will be magnetic field produced will be oriented along the length of the coil.oriented along the length of the coil.(Fig 9.1) (Fig 9.1)

Fig 9.1 direction of the magnetic Fig 9.1 direction of the magnetic fieldfield

• The greater the current, the greater The greater the current, the greater the strength of the magnetic field, all the strength of the magnetic field, all other factors being equalother factors being equal. .

• If we place a magnetic object near If we place a magnetic object near such a coil for the purpose of making such a coil for the purpose of making that object move when we energize that object move when we energize the coil with electric current, we have the coil with electric current, we have what is called a solenoid. what is called a solenoid.

• The movable magnetic object is The movable magnetic object is called an armature, and most called an armature, and most armatures can be moved with either armatures can be moved with either direct current (DC) or alternating direct current (DC) or alternating current (AC) energizing the coil. The current (AC) energizing the coil. The polarity of the magnetic field is polarity of the magnetic field is irrelevant for the purpose of irrelevant for the purpose of attracting an iron armature. attracting an iron armature.

• Solenoids can be used to electrically Solenoids can be used to electrically open door latches, open or shut open door latches, open or shut valves, move robotic limbs, and even valves, move robotic limbs, and even actuate electric switch mechanisms. actuate electric switch mechanisms. However, if a solenoid is used to However, if a solenoid is used to actuate a set of switch contacts, we actuate a set of switch contacts, we have a device so useful it deserves have a device so useful it deserves its own name: the relay. its own name: the relay.

2. Relay2. Relay

• Relays are extremely useful when we Relays are extremely useful when we have a need to control a large have a need to control a large amount of current and/or voltage amount of current and/or voltage with a small electrical signal. with a small electrical signal.

• The relay coil which produces the The relay coil which produces the magnetic field may only consume magnetic field may only consume fractions of a watt of power, while the fractions of a watt of power, while the contacts closed or opened by that contacts closed or opened by that magnetic field may be able to conduct magnetic field may be able to conduct hundreds of times that amount of hundreds of times that amount of power to a load. In effect, a relay acts power to a load. In effect, a relay acts as a binary (on or off) amplifier. as a binary (on or off) amplifier.

Fig 9.2 Load controlled by a Fig 9.2 Load controlled by a relayrelay

• In Fig 9.2, the relay's coil is In Fig 9.2, the relay's coil is energized by the low-voltage (12 Venergized by the low-voltage (12 VDCDC) ) source, while the single-pole, single-source, while the single-pole, single-throw (SPST) contact interrupts the throw (SPST) contact interrupts the high-voltage (480 Vhigh-voltage (480 VACAC) circuit. ) circuit.

• It is quite likely that the current It is quite likely that the current required to energize the relay coil required to energize the relay coil will be hundreds of times less than will be hundreds of times less than the current rating of the contact. the current rating of the contact. Typical relay coil currents are well Typical relay coil currents are well below 1 amp, while typical contact below 1 amp, while typical contact ratings for industrial relays are at ratings for industrial relays are at least 10 amps. least 10 amps.

• One relay coil/armature assembly One relay coil/armature assembly may be used to actuate more than may be used to actuate more than one set of contacts. Those contacts one set of contacts. Those contacts may be normally-open, normally-may be normally-open, normally-closed, or any combination of the closed, or any combination of the two. two.

• As with switches, the "normal" state As with switches, the "normal" state of a relay's contacts is that state of a relay's contacts is that state when the coil is de-energized, just as when the coil is de-energized, just as you would find the relay sitting on a you would find the relay sitting on a shelf, not connected to any circuit. shelf, not connected to any circuit.

• Compare with transistors, relays Compare with transistors, relays have following advantages: have following advantages:

1.1. Relays can switch AC and DC, transistors Relays can switch AC and DC, transistors can only switch DC. can only switch DC.

2.2. Relays can switch high voltages, Relays can switch high voltages, transistors cannot. transistors cannot.

3.3. Relays are a better choice for switching Relays are a better choice for switching large currents (> 5A). large currents (> 5A).

4.4. Relays can switch many contacts at Relays can switch many contacts at once. once.

3. Contactor3. Contactor

• When a relay is used to switch a large aWhen a relay is used to switch a large amount of electrical power through its comount of electrical power through its contacts, it is designated by a special namntacts, it is designated by a special name: contactor. e: contactor. In other words, aIn other words, a contact contactor is a large relay, usually used to switch or is a large relay, usually used to switch current to an electric motor or other higcurrent to an electric motor or other high-power load. h-power load.

• Contactors typically have multiple contaContactors typically have multiple contacts, and those contacts are usually (but cts, and those contacts are usually (but not always) normally-opennot always) normally-open （（ FFig 9.3ig 9.3 ）） ,, so that power to the load is shut off whe so that power to the load is shut off when the coil is de-energized. Perhaps the mn the coil is de-energized. Perhaps the most common industrial use for contactorost common industrial use for contactors is the control of electric motors. s is the control of electric motors.

Fig 9.3 AC contactorFig 9.3 AC contactor

• The top three contacts switch the The top three contacts switch the respective phases of the incoming 3-respective phases of the incoming 3-phase AC power, typically at least 380 phase AC power, typically at least 380 Volts for motors 1 horsepower or Volts for motors 1 horsepower or greater. The lowest contact is an greater. The lowest contact is an "auxiliary" contact which has a current "auxiliary" contact which has a current rating much lower than that of the large rating much lower than that of the large motor power contacts, but is actuated motor power contacts, but is actuated by the same armature as the power by the same armature as the power contacts. contacts.

• The auxiliary contact is often used in The auxiliary contact is often used in a relay logic circuit, or for some other a relay logic circuit, or for some other part of the motor control scheme, part of the motor control scheme, typically switching 120 Volt AC power typically switching 120 Volt AC power instead of the motor voltage. One instead of the motor voltage. One contactor may have several auxiliary contactor may have several auxiliary contacts, either normally-open or contacts, either normally-open or normally-closed, if required. normally-closed, if required.

• Large electric motors can be protected Large electric motors can be protected from damage through the use of from damage through the use of overload heaters and overload contacts overload heaters and overload contacts of thermal overloads. If the series-of thermal overloads. If the series-connected heaters get too hot from connected heaters get too hot from excessive current, the normally-closed excessive current, the normally-closed overload contact will open, de-overload contact will open, de-energizing the contactor sending power energizing the contactor sending power to the motor. to the motor.

This is the End of the TextThis is the End of the Text

Reading materialsReading materials

1. Time Relay1. Time Relay

• Some relays are constructed with a Some relays are constructed with a kind of "shock absorber" mechanism kind of "shock absorber" mechanism attached to the armature which attached to the armature which prevents immediate, full motion prevents immediate, full motion when the coil is either energized or when the coil is either energized or de-energized. de-energized.

• This addition gives the relay the This addition gives the relay the property of time-delay actuation. property of time-delay actuation. Time-delay relays can be Time-delay relays can be constructed to delay armature constructed to delay armature motion on coil energization, de-motion on coil energization, de-energization, or both.energization, or both.

• Time-delay relay contacts must be Time-delay relay contacts must be specified not only as either normally-specified not only as either normally-open or normally-closed, but whether open or normally-closed, but whether the delay operates in the direction of the delay operates in the direction of closing or in the direction of opening. closing or in the direction of opening. The following is a description of the The following is a description of the four basic types of time-delay relay four basic types of time-delay relay contacts. contacts.

• First we have the normally-open, timed-First we have the normally-open, timed-closed (NOTC) contactclosed (NOTC) contact （（ Fig 9.4Fig 9.4 ）） . Thi. This type of contact is normally open when s type of contact is normally open when the coil is unpowered (de-energized). Ththe coil is unpowered (de-energized). The contact is closed by the application of e contact is closed by the application of power to the relay coil, but only after thpower to the relay coil, but only after the coil has been continuously powered foe coil has been continuously powered for the specified amount of time. r the specified amount of time.

• In other words, the direction of the contIn other words, the direction of the contact's motion (either to close or to open) iact's motion (either to close or to open) is identical to a regular NO contact, but ts identical to a regular NO contact, but there is a delay in closing direction. Becahere is a delay in closing direction. Because the delay occurs in the direction of cuse the delay occurs in the direction of coil energization, this type of contact is aloil energization, this type of contact is alternatively known as a normally-open, oternatively known as a normally-open, on-delay. n-delay.

Fig 9.4 Timing diagram of NOTC's Fig 9.4 Timing diagram of NOTC's operation operation

• Next we have the normally-open, Next we have the normally-open, timed-open (NOTO) contact (Fig 9.5). timed-open (NOTO) contact (Fig 9.5). Like the NOTC contact, this type of Like the NOTC contact, this type of contact is normally open when the contact is normally open when the coil is unpowered (de-energized), and coil is unpowered (de-energized), and closed by the application of power to closed by the application of power to the relay coil. the relay coil.

• However, unlike the NOTC contact, However, unlike the NOTC contact, the timing action occurs upon de-the timing action occurs upon de-energization of the coil rather than energization of the coil rather than upon energization. Because the upon energization. Because the delay occurs in the direction of coil delay occurs in the direction of coil de-energization, this type of contact de-energization, this type of contact is alternatively known as a normally-is alternatively known as a normally-open, off-delay: open, off-delay:

Fig 9.5 Timing diagram of NOTO's Fig 9.5 Timing diagram of NOTO's operationoperation

• Normally-closed, timed-open. Normally-closed, timed-open. Abbreviated "NCTO", these relays Abbreviated "NCTO", these relays close immediately upon coil de-close immediately upon coil de-energization and open only if the coil energization and open only if the coil is continuously energized for the is continuously energized for the time duration period. Also called time duration period. Also called normally-closed, on-delay relays. normally-closed, on-delay relays.

• Normally-closed, timed-closed. Normally-closed, timed-closed. Abbreviated "NCTC", these relays Abbreviated "NCTC", these relays open immediately upon coil open immediately upon coil energization and close after the coil energization and close after the coil has been de-energized for the time has been de-energized for the time duration period. Also called normally-duration period. Also called normally-closed, off -delay relays. closed, off -delay relays.

2. Novel controller2. Novel controller

• Recent developments in drive Recent developments in drive electronics have allowed efficient electronics have allowed efficient and convenient control of these and convenient control of these motors, where this has not motors, where this has not traditionally been the case. The traditionally been the case. The newest advancements allow for newest advancements allow for torque generation down to zero torque generation down to zero speed. speed.

• This allows the polyphase AC This allows the polyphase AC induction motor to compete in areas induction motor to compete in areas where DC motors have long where DC motors have long dominated, and present an dominated, and present an advantage in robustness of design, advantage in robustness of design, cost, and reduced maintenance. Hcost, and reduced maintenance. Here ere are some examples:are some examples:

• A motor soft starter connects the A motor soft starter connects the motor to the power supply through a motor to the power supply through a voltage reduction device and voltage reduction device and increases the applied voltage increases the applied voltage gradually or in steps.gradually or in steps.

Fig 9.6 Fig 9.6 QJ Series auto-reduced vQJ Series auto-reduced voltage starter oltage starter

• QJ Series auto-reduced voltage QJ Series auto-reduced voltage starter (Fig 9.6) is applicable to starter (Fig 9.6) is applicable to infrequent reduced-voltage start up infrequent reduced-voltage start up and stop of AC 50Hz three-phase and stop of AC 50Hz three-phase squirrel-cage induction motor with squirrel-cage induction motor with voltage of 380V and power of 10, 14, voltage of 380V and power of 10, 14, 28, 40, 55 and 75kW in general 28, 40, 55 and 75kW in general industry. industry.

• When the tapped autotransformer When the tapped autotransformer starts, it reduces the power supply starts, it reduces the power supply voltage, so that the starting current voltage, so that the starting current reduces. This product also provides reduces. This product also provides with thermal relay and under-voltage with thermal relay and under-voltage tripping gear. tripping gear.

• When the motor is overloaded or the When the motor is overloaded or the voltage of the line is at a certain voltage of the line is at a certain value below the rated voltage, the value below the rated voltage, the motor will be switched off from the motor will be switched off from the power supply to protect the motor.power supply to protect the motor.

Fig 9.7 Fig 9.7 DK-1B type controller DK-1B type controller

• DK-1B type controller (Fig 9.7) in TKZ DK-1B type controller (Fig 9.7) in TKZ series speed-adjustment and control series speed-adjustment and control combination device is speed-combination device is speed-adjustment motor’s direct control adjustment motor’s direct control unit. It can realize wide-range unit. It can realize wide-range stepless speed adjustment by stepless speed adjustment by operating appointed potentiometer. operating appointed potentiometer.

• DK-1B can be equipped with ZC-1A DK-1B can be equipped with ZC-1A operator to work as single set operator to work as single set manual speed adjustment and manual speed adjustment and control; be equipped with DDZ control; be equipped with DDZ adjustor to work as single set adjustor to work as single set automatic speed adjustment and automatic speed adjustment and control ;control ;

• be equipped with TC-1A co-operator be equipped with TC-1A co-operator and ZC-1A operator to realize multi-and ZC-1A operator to realize multi-set synchronous or proportional set synchronous or proportional running; and be combined with DDZ running; and be combined with DDZ adjustor ZC-1A operator to realize adjustor ZC-1A operator to realize multi-set automatic synchronous or multi-set automatic synchronous or proportional running.proportional running.

3. Experiment material3. Experiment material

• Relay-contactor Control of three-Relay-contactor Control of three-phase induction motor phase induction motor

1 Objectives1 Objectives– 1. To be familiar with relay, contactor, 1. To be familiar with relay, contactor,

and other controlling devices;and other controlling devices;– 2. To understand the controlling circuits 2. To understand the controlling circuits

of three-phase induction motors.of three-phase induction motors.

• 2 Apparatus and Equipments2 Apparatus and Equipments

• The apparatus and equipments are The apparatus and equipments are listed in table 9.1.listed in table 9.1.

Table 9.1 The apparatus and Table 9.1 The apparatus and equipmentsequipments

• 3 Approach of the Experiment3 Approach of the Experiment

• 1. The direct starting of the three-phase 1. The direct starting of the three-phase induction motorinduction motor

• (1) Be familiar with the structures of (1) Be familiar with the structures of devices (see Fig 9.8) and their terminals. devices (see Fig 9.8) and their terminals. Distinguish the normal closed contacts and Distinguish the normal closed contacts and normal open contacts of the main normal open contacts of the main contactor KM. Write down the data of the contactor KM. Write down the data of the induction motor.induction motor.

Fig 9.8 Experiment board for Fig 9.8 Experiment board for relay-contactor controlrelay-contactor control

• (2) Complete following experiment (2) Complete following experiment steps after finishing the circuit steps after finishing the circuit connection (Fig 9.9)connection (Fig 9.9)– Turn on the power supply (air-breaker Turn on the power supply (air-breaker

Q)Q)– Start the induction motor Start the induction motor directlydirectly

(button SB2)(button SB2)– Stop the motor by the button SB1Stop the motor by the button SB1

Fig 9.9 The direct starting of Fig 9.9 The direct starting of the three-phase induction the three-phase induction motor motor

• * Observe the operation of the contact* Observe the operation of the contactor KM and the motoror KM and the motor– Start the motor by button SBStart the motor by button SB22, then turn off , then turn off

the power supply by the air-breaker Q to stothe power supply by the air-breaker Q to stop the motor.p the motor.

– Turn on the power supply (air-breaker Q) agTurn on the power supply (air-breaker Q) againain

• * Observe the operation of the motor * Observe the operation of the motor and understand low-voltage protectioand understand low-voltage protection of the circuit.n of the circuit.– Intermittent operation: turn off the power sIntermittent operation: turn off the power s

upply (Q), remove the auxiliary contact conupply (Q), remove the auxiliary contact connected between the modes a and b, turn on nected between the modes a and b, turn on the power supply (Q) again, then operate ththe power supply (Q) again, then operate the button SBe button SB22

• * Understand the function of the * Understand the function of the auxiliary contact acting as a self-auxiliary contact acting as a self-locked contact.locked contact.

• 2. Rotating and inverse rotating of an 2. Rotating and inverse rotating of an induction motor induction motor

• The circuit is shown in Fig 9.10The circuit is shown in Fig 9.10

• * Observe the operation of the * Observe the operation of the motor and understand the motor and understand the functions of the auxiliary functions of the auxiliary contacts.contacts.

Fig 9.10 Rotating and inverse Fig 9.10 Rotating and inverse rotating of an induction motor rotating of an induction motor

• 4 Discussions4 Discussions

• 1. Point out the protective functions 1. Point out the protective functions in the circuit shown in Fig 9.10;in the circuit shown in Fig 9.10;

• 2. Point out the self-locked contacts 2. Point out the self-locked contacts and inter-locked contacts;and inter-locked contacts;

• 3. Whether can the fuse and thermal 3. Whether can the fuse and thermal overload relay replace each other?overload relay replace each other?

This is the End ofThis is the End of the Reading materials the Reading materials

ExercisesExercises

• Ready to go?Ready to go?

1. Put the Phrases into 1. Put the Phrases into EnglishEnglish

• 1) 1) 控制电路控制电路• 22 ）磁场）磁场• 33 ）其它因数）其它因数• 44 ）线圈通电）线圈通电• 55 ）关上阀门）关上阀门

Show the Answer

• 66 ）继电器线圈）继电器线圈• 77 ）常闭触点）常闭触点• 88 ）同时合上很多触点）同时合上很多触点• 99 ）电动机）电动机• 1010 ）交流接触器）交流接触器

Show the Answer

2. Put the Phrases into 2. Put the Phrases into ChineseChinese

• 11 ）） starting and stopping the motor starting and stopping the motor • 22 ）） predetermined mannerpredetermined manner

• 33 ）） forwardforward or reverse rotation or reverse rotation

• 44 ）） digital input signalsdigital input signals

• 55 ）） be oriented along the length of be oriented along the length of the coilthe coil

Show the Answer

• 66 ）） attracting an iron armatureattracting an iron armature

• 77 ）） industrial relays industrial relays • 88 ） ） sit on a shelfsit on a shelf• 99 ） ） high-power load high-power load • 1010 ）） auxiliary contactauxiliary contact

Show the Answer

3. Sentence Translation3. Sentence Translation

• 1) 1) A motor controller is connected to a A motor controller is connected to a power source such as a battery pack or power source such as a battery pack or power supply, and control circuitry in the power supply, and control circuitry in the form of analog or digital input signals.form of analog or digital input signals.

• 11 ）电动机控制器可以直接接在电池组上或）电动机控制器可以直接接在电池组上或电源上，用模拟或数字输入信号控制（电电源上，用模拟或数字输入信号控制（电动机）电路。 动机）电路。

• 2) The greater the current, the 2) The greater the current, the greater the strength of the magnetic greater the strength of the magnetic field, all other factors being equal. field, all other factors being equal.

• 22 ）在其他条件不变的情况下电流越大，则）在其他条件不变的情况下电流越大，则磁场的强度越大。 磁场的强度越大。

• 3) 3) Relays are extremely useful when we Relays are extremely useful when we have a need to control a large amount of have a need to control a large amount of current and/or voltage with a small electcurrent and/or voltage with a small electrical signal.rical signal.

• 33 ）当我们要用一个小的电信号去控制大电）当我们要用一个小的电信号去控制大电流或高电压时，继电器十分有用。 流或高电压时，继电器十分有用。

• 4) It is quite likely that the current requir4) It is quite likely that the current required to energize the relay coil will be hunded to energize the relay coil will be hundreds of times less than the current rating reds of times less than the current rating of the contact. of the contact.

• 44 ）给继电器线圈供电的电流是触点额定电）给继电器线圈供电的电流是触点额定电流的几百分之一。 流的几百分之一。

• 5) When a relay is used to switch a 5) When a relay is used to switch a large amount of electrical power large amount of electrical power through its contacts, it is designated through its contacts, it is designated by a special name: contactor.by a special name: contactor.

• 55 ）当继电器用于作为大电流的开关时，就）当继电器用于作为大电流的开关时，就有一个指定的名称：接触器。 有一个指定的名称：接触器。

44 ．． TranslationTranslation

• 1) Numerical control or numerically 1) Numerical control or numerically controlled (NC) machine tools are controlled (NC) machine tools are machines that are automatically machines that are automatically operated by commands encoded on operated by commands encoded on a digital medium. a digital medium.

• NC machines were first developed NC machines were first developed soon after World War II and made it soon after World War II and made it possible for large quantities of the possible for large quantities of the desired components to be very desired components to be very precisely and efficiently produced precisely and efficiently produced (machined) in a reliable repetitive (machined) in a reliable repetitive manner. manner.

Show the Answer

• 2) Apple2) Apple iPod nano iPod nano (Fig 9.11) (Fig 9.11)

• Third Gen. Green (8 GThird Gen. Green (8 GB, MB253LL/A) DigitaB, MB253LL/A) Digital Media Player l Media Player

• The larger, brighter display means The larger, brighter display means amazing picture quality. It features amazing picture quality. It features an anodized aluminum top and an anodized aluminum top and polished stainless steel back. It'll polished stainless steel back. It'll wow you for hours. Play up to 5 hours wow you for hours. Play up to 5 hours of video or up to 24 hours of audio on of video or up to 24 hours of audio on a single charge. a single charge.

• iTunes provides music, movies, TV showiTunes provides music, movies, TV shows, games and more. All those features wis, games and more. All those features within a wafer-thin, 6.5-mm profile makes thin a wafer-thin, 6.5-mm profile makes iiPod nanoPod nano a tiny big attraction you'll just a tiny big attraction you'll just love carrying around! love carrying around!

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This is the End of the This is the End of the ExercisesExercises

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