电气自动化专业英语试题及答案一

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电气自动化专业英语试题及答案（一）

　　电气自动化专业英语是一门比较难学的课程，很多同学对这门课程比较头痛，同学们要加倍努力才能学好电气自动化专业英语。下面是阳光网小编给大家整理的电气自动化专业英语试题及答案，欢迎大家学习参考。

电气自动化专业英语试题及答案（一）

　　电气自动化专业英语试题及答案(一)

　　电气工程《专业英语》试题

　　Ⅰ.Reading comprehension(20points): Passage one: The traditional mechanical wristwatch uses a balance wheel and hairspring to keep time. In a digital watch these mechanical parts have been replaced by vibrating quartz crystal controlled by minute electronic circuits. The artificial quartz crystals used in digital watches are designed to vibrate up to 32,768 cycles per second when the current from a battery is passed through them. These vibrations produce electric pulses. As the pulses travel through the electronic circuits of the microchip, their rate is gradually halved. The result creates a pulse rate of one per second. Each one-second pulse triggers the microchip to send signals to the digital display to advance the numerals by one second. The pulses are also used to control different functions such as the hour display, date and alarm signal.

　　①The best title of this article is . A. Mechanical wristwatch. C. Digital Watch B. Electronic circuits . D. Counter. ②How many times do the electronic circuits of the microchip halve when creating a pulse rate of one per second? A. 10 B. 15 C. 13 D. 12 Passage two: The higher the frequency of the analogue signal, the more often it must be sampled. However, it is usually adequate to sample a signal at twice its highest frequency. Each binary digit used to show a binary value is known as a bit. The accuracy of conversion is limited by the number of binary bits used by the ADC . If the conversion is made using a four-bit ADC, only sixteen different binary values can be produced. The smallest value is 0000 and the largest is 1111. If an 8-bit ADC is used, then 256 different digital values can be produced. When a measurement of the analogue signal does not coincide with one of these binary values, it must be rounded up or down ① If the analogue signal is u=sin(200 π t), then the adequate sampling frequency must be more .A 50Hz. C. 100Hz than B 200Hz D. 50πHz ②If the conversion is made using a ten-bit ADC, different binary values can be produced. A 1024. C. 256 B.512 D. 10 ③Explain the underlining words in Chinese according to the articles (1) minute ( ) (2) halved ( ) (3) advance ( ) (4) rounded down or up( ) (5) trigger ( ) Ⅱ. Please translate following four passages into Chinese(40points): Passage one (10points) The salient construction features of the three-phase induction motor are described in Sec.5.3. Because the induction machine is singly excited, it is necessary that both the magnetizing current and the power component of the current flow in the same lines. Moreover, because of the presence of an air gap in the magnetic circuit of the induction machine, an appreciable amount of magnetizing current is needed to establish the flux per pole demanded by the applied voltage. Usually, the value of the magnetizing current for three-phase induction motors lies between 25 and 40% of the rated current. Consequently, the induction motor is found to operate at a low power factor at light loads and at less than unity power factor in the vicinity of rated output. Passage two (15points) Performance Optimization of Induction Motors During Voltage-Controlled Soft Starting Abstract—This paper deals with the performance optimization of medium/high-power induction motors during soft starting by eliminating the supply frequency torque pulsations, and by keeping the line current constant at the preset value. Starting torque pulsations are eliminated by triggering back-to-back-connected thyristors at proper points on the first supply voltage cycle. Line current during starting can be kept constant at any preset value by a

　　simple strategy composed of successive cosinusoidal and constant function segments of the triggering angle. These strategies are implemented by the use of an 8-b microcontroller. Transient performance analyses of the system are carried out by means of a hybrid ABC/dq machine model which takes into account the three-phase, two-phase, and disconnected modes of operation in terms of actual stator variables. Experimental results obtained on a custom-design test bed are found to be in good agreement with the theoretical ones. Index Terms--Induction motor, soft starter, torque pulsations. Passage three(5points) An electric transmission line is modeled using four parameters that affect its performance characteristics. The four parameters are the series resistance, series inductance, shunt capacitance, and shunt conductance. The line resistance and inductive reactance are of importance in many problems of interest. For some studies it is possible to omit the shunt capacitance and conductance and thus simplify the equivalent circuit considerably. Passage four(10points) Definition of a control system may be defined in a variety of ways, the most basic definition is as follows: A control system is a group of components assembled in such a way as to regulate energy input in order to achieve the desired result. For example, in a temperature control system, thermal energy is regulated to maintain temperature at a pre-determined value or within a certain range (Fig.1).

　　Ⅲ.Please write one or two sentences for each given technical word to describe its function.(10points) a. Diode b. Rectifier c. Transformer d. Resistor e. Aerial Ⅳ.Please translate the following two sentences into English.(5points) 1. 就磁场分布对转矩的影响而言，计算结果与实验结果一致。

　　2. 本文提出一种新的设计方法，重点放在其推导思路上。它和传统方法相比有很多优点，最后举例说明了该方法的.应用。

　　Ⅴ.Filling the English meanings in the blanks respectively. (25points) 万用表集成电路局域网运算放大器积分状态变量数据总线谐波换向器晶闸管发电厂正反馈绕组阻尼系数逻辑运算占空比中性点示波器继电器涡流损耗自耦变压器有功功率传感器逆变器线电压

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