篇一：电气工程及其自动化,专业英语课程论文
重庆邮电大学移通学院
《电气工程及其自动化专业英语》课程论文
年级专业电气工程与自动化
姓名孙猜胜
学号
Three-phase asynchronous motor
Abstract:
The three-phase asynchronous motor is motor's one kind.Compared with single phase asynchronous motor, three-phase asynchronous motor operating performance is good, and can save various materials.Has the structure to be simple, the manufacture is easy, firm durable, the service is convenient, cost inexpensive ,drag the ability is good,and so on a series of merits. thus becomes in each kind of electrical machinery the output to be biggest utilizes the broadest one kind of electric motor.
Key words:
Moror Motor starting Star delta Starting
Three-phase asynchronous motor principle:
When the stator winding through into the three-phase ac three-phase symmetric arises when a synchronous speed n1 along the stator and rotor round for space in a clockwise rotation magnetic field. Because of a rotating magnetic field rotating speed to n1, rotor conductor of the static beginning, so the rotor conductor will cut the stator and produce a rotating magnetic field induction emf (induction emf direction DingZe judge with the right hand). Because the child is short circuit loop ends conductor short meet, in the role of the induced emf, will produce the rotor conductor with induction emf direction basic consistent induced current. The rotor current-carrying conductor at stator magnetic field is the role of the electromagnetic force (the direction of the force with the left hand DingZe judge). The electromagnetic force of the rotor axis electromagnetic torque, drive along the rotor rotating magnetic field rotation direction.[1]Through the above analysis can be summed up the motor principle: when the three-phase motor stator winding (each differ 120 KWH Angle), ventilation with three-phase ac, will produce a rotating magnetic field, the rotating magnetic field cutting rotor winding, and thus to the rotor winding induced current (rotor winding is closed access), load flow of rotor stator conductor under the action of a rotating magnetic field will produce the electromagnetic force, thus in the motor shaft formed on the electromagnetic torque, driving motor rotation, and motor rotation direction and the rotating magnetic field in the same direction.
The structure of three-phase asynchronous motor:
Types of three-phase asynchronous motor, but all kinds of three-phase asynchronous motor is the same basic structure, they are the stator and rotor of these two basic components, the stator and rotor has a certain air gap between. In addition, end caps, bearings, cable boxes, rings and other accessories,
1). Stator part
Stator is used to generate the rotating magnetic field.Stator Three-phase motors
generally shell, stator core, stator windings and other parts.
a. Shell
Three-phase motor casing including base,end caps,bearing caps,rings,such as junction boxes and comp onents
b. Stator Core
Induction motor stator core is part of the motor circuit from 0.35mm ~ 0.5mm thick coated with a thin insulating paint from silicon,
c. The stator windings
Three-phase motor stator windings are part of the circuit,there are three-phase three-phase motor windings,summetrical three-phase current access,it will have a rotating magnetic field.Three-phase winding consists of three separate components of the winding, and each has a number of coil windings connected.Is a phase of each winding, each winding in the space angle difference between the 120 ° electrical[2].
2). Rotor part
a. Rotor Core
With 0.5mm thick steel from, set in the shaft, the role and the same stator core, on the one hand, as part of the motor magnetic circuit, on the one hand to place the rotor windings.
b. Rotor windings
The rotor winding induction motor winding is divided into two kinds of cage-shaped and which is divided into winding rotor asynchronous motor with cage induction motor.
3). Other parts of
Other parts including the cover, fans, etc.
Induction motor starting methods:
There are several general methods of starting induction motors: full voltage, reduced voltage,wyes-delta,and part winding types.The reduced voltage type can include solid state starters, adjustable frequency drives, and autotransformers.The following is the most common method.
1).Full voltage
The full voltage starting method, also known as across the line starting, is the easiest method to employ, has the lowest equipment costs, and is the most reliable. This method utilizes a control to close a contactor and apply full line voltage to the motor terminals. This method will allow the motor to generate its highest starting torque and provide the shortest acceleration times.This method also puts the highest strain on the power system due to the high starting currents that can be typically six to seven times the normal full load current of the motor.
2).Autotransformer
The motor leads are connected to the lower voltage side of the transformer. The most common taps that are used are 80%, 65%, and 50%. At 50% voltage the current on the primary is 25% of the full voltage locked rotor amps. The motor is started with this reduced voltage, and then after a pre-set condition is reached the connection is switched to line voltage. This condition could be a preset time, current level, bus volts,
or motor speed. The change over can be done in either a closed circuit transition, or an open circuit transition method. In the open circuit method the connection to the voltage is severed as it is changed from the reduced voltage to the line level. Care should be used to make sure that there will not be problems from transients due to the switching. This potential problem can be eliminated by using the closed circuit transition. With the closed circuit method there is a continuous Voltage applied to the motor. Another benefit with the autotransformer starting is in possible lower vibration and noise levels during starting.
3).Star delta Starting
This approach started with the induction motor,the structure of each phase of the terminal are placed in the motor teminal box ,This allows the motor star connection in the initial start up,and then re-connected into a triangle run..The initial start time when the voltage is reduced to the original star connection,the starting current and starting torque by 2/3. Depending on the application on,the motor switch to the triangle in the rotational speed of between 50% and the maximum speed.Must be noted that the same problems,including the previously mentioned switch method ,if the open circuit method,the transition may be a transient problem.This method is often used in lesst than 600V motor,the rated voltage 2.3KV and higher are not suitable for star delta motor start method.[3]
4).Series Resistor or Reactor Starting
This method is to use a series resistance or place in the motor loop reactor.In the motor is started, a resistor to limit current and make the motor at the input voltage drop. Therefore plays a role of limiting current at startup.On the small motor series resistor startup mode used more frequently
Conclusion:
There are many ways asynchronous motor starting, each method has its own benefits, according to the constraints of power systems,equipment costs, load the boot device to select the best method.
References:
[1]Tang Tianhao Fundamentals of Electrical Machines and Drives [M] Beijing China Machine Press2013.7118-137
[2] Wang Liming English for Electrical Engineering and Automation [M] Beijing Tsinghua University Press 2012.12 61-64
[3]Stephen J.Chapman Electromechanics [M] AmericaElectronic Industry Press340-370
篇二：电气工程及其自动化专业英语个人简历(English)
Personal resume
Basic personal information
Name:Li Wenbin Gender: Malenation: Han Date of birth: 1991.06.12Household register: henan
Political affiliation:A member of the Communist Youth League
The specialty: Electrical engineering and automationEducation：Bachelor's degree Height: 180cmContact telephone number: 18737199160 E-MAIL: lwb564226349@126.com
Contact address: Zhao Zhai Village Zi Ling town Qinyang city Henan province
Zip code: 454592
Home address: Zhao Zhai Village Zi Ling town Qinyang city Henan province
Zip code: 454592
Occupation skill ? Foreign language ability： CET-4 CET-6
? Computer skills：NCRE-2
? Familiar with computer operation, skilled use of office and Internet series of office software
application
? Master the C language, assembly language, MATLAB, CAD and so on, has the strong ability
of programming and program analysis.
Education experience 2011.9-2015.6 Henan University of Technology
2008.9-2011.6 Qinyang First Middle High School
Professional coursesMajor courses： Circuit theory, modern control theory and sampling system, power electronics technology, power supply and distribution system, the principle of automatic control,
Motor learning, analog electronic technology, digital electronic technology, distributed control system, PLC principle and application, Single chip microcomputer principle and interface technology,Power system analysis etc.
Minor courses: microeconomics, macroeconomics, introduction to the world economy, international financial, accounting, Multi-National Corporation and direct investment, international trade, business English etc.
Social practice/Internship experience 2015 July internship in Shanghai Hualian Supermarket
Design in 2015 August involved in Shanghai electric scientific research, test switch (mainly used for high pressure two times side)
Self evaluationElectrical solid theoretical foundation, abundant project experience; familiar with electric power system load calculation, short circuit analysis and power flow distribution calculation;
familiar with a variety of main electrical equipment and related standards, rich experience in project design. Skilled in 3D design software and Office office automation software, serious and responsible work, cooperation consciousness and organizational skills, able to work under pressure.
篇三：电气工程及其自动化本科毕业设计(论文)外文资料中英文对照翻译
本科毕业设计（论文）
中英文对照翻译
院（系部） 电气工程与自动化学院专业名称电气工程及其自动化 年级班级
学生姓名
指导老师
Unattended substation and substation automation
The development of automatic reclosing made the unattended substation practical .Automatic operation ,without the continuous presence of an attendant(operator),was first tried on the synchronous converter substations supplying an interurban electric railway in 1914.In the early 1920s,the development of automatic reclosing ,protective relays ,and means for automatic control of voltage made it possible for ac substations to be completely automatic .During the period when the substations had to be controlled manually ,it was necessary that they handle enough power to justify the operator`s wages .This dictated large stations ,frequently serving large areas by means of many feeders .The feeders that served the more distant parts of an area had to go a long way before they picked up any load .Furthermore ,as the load on a large substation grows ,transformer capacity has to be added .This increases the short-circuit current on the secondary side sometimes the short-circuit capacity exceeds the interrupting capacity of the circuit breakers already installed .Appropriate remedies include bus sectionalizing ,the installation of reactors or some combination of the two .Such measures are frequently expensive and inconvenient and they constitute an undesirable limitation on operating flexibility.
Once the unattended substation became a reality ,the substation could be made smaller .Located nearer the load ,and long feeders were no longer necessary .This new method of distribution had become available since load growth could now be accommodated by installing
another substation that could carry parts of the area loads formerly carried by adjacent substations .Usually ,there is no interconnection between the circuits energized by the various substations .Consequently ,there is no increase in short-circuit severity .however ,at the distribution level ,tie switches are used to switch feeders or feeder sections between transformers in the same station or to adjacent substations for substation transformer load management.
Automatic control ha(本文来自：wwW.xIAocAofaNwEn.com 小 草范 文 网:电气工程与自动化英语论文)s been applied to larger and larger substations ,and to many hydroelectric generating stations .It is also used on individual circuits and equipment in many attended stations .For example ,even in many stations where an operator is on duty ,outgoing overhead feeders are controlled by automatic reclosing relays .Under some circumstances ,it may be impractical to make a station completely automatic .These circumstances could exist because of technical ,economic ,or safety considerations .A station need not be attended even though it is not fully automatic ,it is possible to control a station from another location ,such as a larger attended station or the system operating office .This can be done by means of supervisory control(a form of remote control).
By means of a SCADA system ,an operator at a dispatch center can cause operations such as the opening and closing of breakers ,the starting and stopping of condensers ,and the changing of the taps on transformers with load tap changer .The operator can receive an indication that the operation has been completed .All of this can be done over a voice-grade communication channel .It
is the use of voice-grade ,two-way communication channels that distinguishes supervisory control from direct-wire remote control ;The latter requires one direct-wire circuit for each control from direct-wire remote control ;The latter requires one direct-wire circuit for each controlled device .SCADA equipment supplements automatic control .All of the protective relays and most of the control relays required for automatic control are also necessary when supervisory control is used .Only the initiating devices may be different or omitted .For example a fully automatic synchronous condenser is started and stopped by an initiating device responsive to voltage or current or both .In addition ,there are many protective and control relays .If the condenser is to be controlled by supervisory control ,all the other devices are still necessary ,and only the initiating devices can be omitted.
With the recent revolution in microelectronic performance and costs ,digital automation systems are now being developed for power systems .These automation systems provide an integrated systems concept for protection ,control ,and monitoring functions .The approach utilizes distributed microprocessor-based modules located within the substations and ort on the transmission and distribution system .This provides protection and control decisions out on the system where the data is located .By automatic transmission and distribution systems ,major benefits will be obtained .There include greater utilization of existing facilities ,reduction of communication requirements ,deferral of major system investments ,optimized operations and maintenance ,improved system reliability ,more efficient-system
operation through lower losses and rapid restoration of service after a fault the functions implemented by using this integrated systems approach include :Transmission automation functions and distribution substation and feeder automation functions.
The transformer substation automation and unmanned on duty are the popular topics that the charged barbed wire net adjusts one degree automation realm nowadays, its development power head is just on the up.The abroad has a kind of standpoint to think, the person is subjected to
environment,motion,personality,disease...etc. many factor
influence easily, so oneself be a not dependable factor.Really there aren't a few troubles to being cause by the artificial mistake operation of, seeing from this angle, no man the on duty really can raise to circulate credibility.For example ZHENG4 ZHOU DI4 adjust as early as 1959 to start adopt the remote control technique, more than 30 in the last yearseses never take place a mistake
operation;Again if after power supply bureau in Shenzhen carry out a transformer substation no man on duty, mistake operation the trouble rate lowered 60%.
The transformer substation automation is at the calculator technique and the network correspondence technical foundation up develop.The abroad has already had the dispersion type transformer substation automation to publish in 80's, taking Siemens(SIEMENS) company as an example, that company the 1st whole dispersion type transformer substation automation LSA678 as early as 1985 circulates in the German Hanover devotion, the transformer
substation that go to various electric voltage grade that 1993