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VI. Запомните и воспроизведите диалог.Стр 1 из 10Следующая ⇒
A: Do you know that since the loop continues rotating through the field the conductors of the loop will always have an alternating e.m.f. induced in them? B: Yes, that is quite right. A: And how can d.c. be obtained from the generator? B: To obtain d.c. from the generator one must convert the generated a.c. to d.c. A: What device converts the generated a.c. to d.c.? B: To my mind the commutator does. A: And how is the action of converting a.c. to d.c. called? B: It is called commutation.
VII. Просмотрите текст и расскажите о коллекторе, употребив следующие слова: one of the slip rings, the other slip ring, along its axis, the ends of the coil, each of the segments of the slip ring, no electrical contact, the shaft, any other part of the armature, the entire slip ring, commutator, its action of converting, commutation, between, is eliminated, is split, are connected to, are insulated, there is, is known as.
Text 4 D.C. Generator Construction and Operation Now you will learn about actual generators and how they are constructed. There are several components essential to the operation of a generator. Once you learn to recognize these components and become familiar with their function, you will find it much easier to do fault-finding and maintenance work on generators. All generators – whether a.c. or d.c. – consist of a rotating part and a stationary part. In most d.c. generators the armature coil is mounted on the rotating part, which is then referred to as the "armature". The field coils are mounted on the stationary part which is then referred to as the "field". In most a.c. generators the field is mounted on the rotating part – the rotor and the armature winding on the stationary part – the stator. In either case there is relative motion between the armature and field coils, so that the armature coils cut through the magnetic lines of force of the field. As a result, an e.m.f. is induced in the armature, causing a current to flow through the outside load. Since the generator supplies electrical power to a load, mechanical power must be put into the generator to cause the rotor to turn and to generate electricity. The generator itself simply converts mechanical power into electrical power. Consequently, all generators must have machines associated with them which will supply the mechanical energy necessary to turn the rotors. These machines are called "prime movers", and may be steam engines, electric motors and so on. In assembling the generator, the fields are mounted in the stator and one end housing is bolted to the stator frame. The armature is then inserted between the field poles and the housing end, with the brush assemblies mounted last. Generator assembly and disassembly varies depending on the size, type and manufacturer. The field windings, when mounted on the pole pieces, form electromagnets which provide the magnetic field necessary for generator action. Field windings can be connected either in series or in parallel (or shunt, as the parallel connection is often called) with the armature. Shunt field windings consist of many turns of fine wire, while series field winding are composed of fewer turns of fairly heavy wire.
Words and Word Combinations
Note: with the brush assemblies mounted last –..., а щеточные устройства устанавливаются последними.
E x e r c i s e s I. Прочитайте и переведите слова и словосочетания: essential, maintenance, stationary, referred to as, motion, function, outside (load), mechanical, to cause, consequently, associated with, necessary, assembling, size, to insert, assemblies, winding, fault-finding, turn, components.
II. Найдите в тексте эквиваленты следующих словосочетаний: работа генератора, вращающаяся часть, неподвижная часть, в любом случае, относительное движение, в результате, сам генератор, при сборке генератора, в зависимости от размера и типа, тонкая проволока, толстая проволока.
III. Вставьте нужное слово. 1. Several components are... to the operation a generator (essential, stationary). 2. As a result an e.m.f.... in the armature causing a current to flow through the outside load (is mounted, is induced). 3. The armature coil... on the rotating part (is mounted, is called). 4. The generator itself simply... mechanical power into electrical power (supplies, converts). 5. These... are called "prime movers" (stators, machines).
IV. Напишите (прочитайте) следующие предложения, поставив сказуемое в пассивной форме в прошедшем и будущем времени. Образец. 1) These machines are called "prime movers". These machines were called... These machines will be called... 2) The parallel connection is often called "shunt". The parallel connection was often called "shunt". The parallel connection will be called "shunt".
1. In assembling the generator, the fields are mounted in the stator and one end housing is bolted to the stator frame. 2. The armature is then inserted between the field poles and the housing end with the brush assemblies mounted last.
V. Выразите согласие или несогласие с данными утверждениями, используя следующие фразы: Yes, it is right; No, it is wrong (парная работа). 1. If you know the components essential to the generator operation you will do fault-finding and maintenance work much easier. 2. In most d.c. generators the armature coil is mounted on the rotating part, which is then referred to as the "armature". 3. The generator itself does not convert mechanical power into electrical power. 4. The generators must have machines which will supply the mechanical energy necessary to turn the rotors. 5. The magnetic fields are not necessary for generator action. 6. Series field windings are composed of many turns of fine wire.
  Живите по правилу: МАЛО ЛИ ЧТО НА СВЕТЕ СУЩЕСТВУЕТ? Я неслучайно подчеркиваю, что место в голове ограничено, а информации вокруг много, и что ваше право...  Что делать, если нет взаимности? А теперь спустимся с небес на землю. Приземлились? Продолжаем разговор...  Что способствует осуществлению желаний? Стопроцентная, непоколебимая уверенность в своем...  Что делает отдел по эксплуатации и сопровождению ИС? Отвечает за сохранность данных (расписания копирования, копирование и пр.)... Не нашли то, что искали? Воспользуйтесь поиском гугл на сайте:
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