機(jī)械專業(yè)外文翻譯--伺服系統(tǒng)-免費(fèi)閱讀
【正文】 , only coil B carries current, and the flux is directed to the right. At 180186。 N39。 旋轉(zhuǎn)磁通的速度叫做同步轉(zhuǎn)速，它由線圈電流的頻率決定。 18 度時(shí)，由于 A 線圈電流在負(fù)值方向上，所以磁通方向向下。適當(dāng)選擇電容值的大小，可改變 IA 相對(duì) E 的相位，使 lA 和 IB 的相位差接近 90 度。 圖 4 圖 4 給出了表示雙極、雙相感應(yīng)電動(dòng)機(jī)的轉(zhuǎn)于、剖面和電路圖。平衡電位計(jì)產(chǎn)生的偏差信號(hào)與控制變換器產(chǎn)生的偏差電壓完全是用于同樣方式。這種伺服系統(tǒng)的框圖如圖 2 所示。伺服系統(tǒng)可按照所用伺服馬達(dá)的類型劃分為電動(dòng)式、液壓式、氣動(dòng)式或機(jī)械式。 為使伺服系統(tǒng)滿足五項(xiàng)基本要求，它必須具有一個(gè)偏差檢測(cè)元件和一個(gè)操縱負(fù)載位移馬達(dá)的控制器。由于這個(gè)原因，并且在傳送大力矩時(shí)，偏差角增大，同步系統(tǒng)只能用丁轉(zhuǎn)動(dòng)刻度盤(pán)和指針，移動(dòng)控制活門(mén)和驅(qū)動(dòng)其他小力矩負(fù)載。 畢業(yè)設(shè)計(jì) (論文 )外文資料翻譯 系 部： 機(jī)械系 專 業(yè)： 機(jī)械工程及自動(dòng)化 姓 名： 學(xué) 號(hào)： 外文出處： 《 Servo Systems》 附 件： ； 。另一方面，伺服系統(tǒng)可提供要求移動(dòng)大負(fù)載的大力矩，只需給輸入軸加上很小的力矩。 二、伺服系統(tǒng)部件 伺服系統(tǒng)包括偏差指示器和按照?qǐng)D 1 方式連接輸入和輸出軸的控制器。本文只討論電動(dòng)伺服系統(tǒng)。若這個(gè)系統(tǒng)用直流馬達(dá)，圖中放大器必須具有將同步系統(tǒng)的交流電壓整流，同時(shí)進(jìn)行功率放大的功能，若使用交流 馬達(dá)，則需要交流放大器圖 2 所示的系統(tǒng)中，輸入軸與輸出軸之間的偏差角，確定了由控制變換器產(chǎn)生并送到伺服放大器的偏差電壓的相位和幅值。 圖 3 CT（控制變換器）的指令一般來(lái)自離 CT 一段距離的同步發(fā)送器轉(zhuǎn)軸的運(yùn)動(dòng)，而平衡電位計(jì)轉(zhuǎn)軸指令則可加到一個(gè)電位計(jì)滑動(dòng)觸點(diǎn)的轉(zhuǎn)子上。定于和轉(zhuǎn)子都是由薄鋼片疊加構(gòu)成的。由于電流流過(guò)兩個(gè)線圈，通過(guò)轉(zhuǎn)子鐵芯的總磁通的幅值是常量，并由定子電流的頻率確定磁場(chǎng)沿電動(dòng)機(jī)軸轉(zhuǎn)動(dòng)的速度。頂行圖示說(shuō)明了供電電流每個(gè)周期內(nèi)，磁通旋轉(zhuǎn)一周的變化。對(duì)于工作在400 周／秒電源的雙極電動(dòng)機(jī)來(lái)說(shuō)，其同步轉(zhuǎn)速為 2400 轉(zhuǎn)／分。和 S39。, the flux is directed downward because coil A carries current in the negative direction. The patterns in the top row show that the flux rotates one revolution for each cycle of the supply current. Flux patterns obtained at intermediate values of phase angle, when current flows in both coils, are given in the second row of Fig. 5. Because the turns of the stator coils are distributed in the slots in such a way that the air gap flux density varies sinusoid ally with angle around the rotor, the flux remains constant in magnitude throughout its rotation, and the speed of rotation is constant. For example, at a phase angle of 45 coil A carries a current whose magnitude is of maximum producing a. flux in the upward direction which is of maximum value. Coil B also carries a current whose magnitude is of maximum producing a flux to the right whose magnitude is of maximum. The vector sum of these two flux ponents at right angles to each other falls at an angle of 45 and has a magnitude equal to the maximum magnitude of either individual ponents, Figure 5 Rotating Field in TwoPhase Induction Motor Figure 6 Relation of Rotating Flux to Rotor Currents and Torque in a TwoPhase Induction Motor The speed at which the flux rotates is called the synchronous speed and depends upon the frequency of the coil currents. For a twopole motor operated from 40U cps power, the synchronous speed is rpm. Trip direction of rotation of the flux in a twophase induction motor is reversed if the terminals of either stator coil are interchanged. In other words, a 180186。, only coil A carries current, and the flux is directed upward along the axis of coil A. At 90186。（圖中假定轉(zhuǎn)子轉(zhuǎn)速近似等于同步轉(zhuǎn)速，且轉(zhuǎn)子電流與轉(zhuǎn)子感應(yīng)電勢(shì)同相）字母 N和 S 代表定子旋轉(zhuǎn)磁場(chǎng)的北極和南極。兩個(gè)成直角的磁通線圈，其合成相量轉(zhuǎn)到 45 度方向，幅值等于每個(gè)單個(gè)線圈的最大幅值。 90 度時(shí)，僅 B 線圈有電流，磁通方向向右。正如圖 4 (e）的相量圖所示，B 線圈電流 IB 因線圈的感抗而滯
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