外文翻譯---電動(dòng)機(jī)的結(jié)構(gòu)特點(diǎn)-其他專業(yè)-免費(fèi)閱讀
【正文】 另外，在圖 中涉及電刷的位置。這使得電流在電機(jī)旋轉(zhuǎn)時(shí)能夠?qū)腚姌欣@組。流過(guò)繞組的直流電流建立了分布在氣隙圓周的磁場(chǎng)，同步電動(dòng)機(jī)的轉(zhuǎn)子也采用這種方式。不同于感應(yīng)電動(dòng)機(jī) 的是同步電動(dòng)機(jī)是雙重激發(fā)的電機(jī)，即能量不僅供給定子也供給轉(zhuǎn)子。圖 （ a）為基本的雙極形式重復(fù)兩次，三相繞組表示為四個(gè)磁極。由于 轉(zhuǎn)子繞組通過(guò)端環(huán)短路，則感應(yīng)電動(dòng)機(jī)形成（轉(zhuǎn)子）電流，電流與磁場(chǎng)相互作用產(chǎn)生電磁轉(zhuǎn)矩，結(jié)果使得電動(dòng)機(jī)運(yùn)動(dòng)起來(lái)。繞組終端與三個(gè)滑環(huán)相連，這樣使得外部的三相導(dǎo)體和轉(zhuǎn)子相連，輸出轉(zhuǎn)速。 the armature windings is located on the stator. This statement is valid even when the synchronous machine operates as a motor. In this mode AC power is applied to the stator winding and DC power is applied to the rotor winding for the purpose of energizing the field poles. Mechanical energy is then taken from the shaft. Note, too, that unlike the induction motor, the synchronous motor is a doubly excited machine。英文翻譯 第 1 頁(yè) 共 8 頁(yè) Construction Features of Electrical Machines The energyconversion process usually involves the presence of two important features in a given electromechanical device. These are the field winding, which produces the flux density, and the armature winding, in which the “working emf is induced. In this section the salient construction features of the principal types of electric machines are described to show the location of these windings, as well as to demonstrate the general position of such machines. Induction Motor This is one of the most rugged and most widely used machines in industry. Its stator is posed of laminations of highgrade sheet steel. The inner surface is slotted to acmodate a threephase winding. In (a) the threephase winding is represented by three coils, the axes of which are 120 electrical degrees apart. Coil aa39。 ., energy is applied to the rotor as well as the stator winding. In fact it is this characteristic which enables this machine to develop a nonzero torque at only one speed —hence the name synchronous. Because the magizing current for the synchronous machine originates from a 英文翻譯 第 4 頁(yè) 共 8 頁(yè) separate source (the DC supply), the airgap lengths are larger than those found in induction motors of parable size and rating. However, synchronous machines are more expensive and less rugged than induction motors in the smaller horsepower ratings because the rotor must be equipped with slip rings and brushes in order to allow the direct current to be conducted to the field winding. Machines Electromechanical energyconversion devices that are characterized by direct current are more plicated than the AC type. In addition to a field winding and armature winding, a third ponent is needed to serve the function of converting the induced AC armature voltage into a DC voltage. Basically the device is a mechan
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