Контрольная работа по Английскому языку на тему: «Контрольно‑практические задания по теме „Машины постоянного тока: генераторы и двигатели“»

Вариант 2

I. Соотнесите части А и В. A.: field coil, voltage source, excitation current, separately excited generator, self excited generator, field current, series generator, compound generator, exciter, amplifier. B.: ток возбуждения, генератор с последовательным возбуждением, источник напряжения, усилитель, катушка возбуждения, генератор смешанного возбуждения, катушка возбуждения, генератор с параллельным возбуждением, генератор независимого возбуждения, генератор с самовозбуждением.

II. Вставьте данные ниже сказуемые в пропущенные места в предложениях. Переведите предложения на русский язык. is, have, supplied, must be connected, drives, may be supplied, is called, will result, can use 9 1. To produce a constant field to use in a generator, the field coils … across a d.c. voltage. 2. The d.c. current in the field coils … the «excitation current». 3. The excitation current … from a separate d.c. voltage. 4. A generator … part of its output to supply a field current. 5. Separately excited generators … two circuits. 6. In a separately excited d.c. generator the field … independent of the armature. 7. With a slight change in the field current, a large change in the load current … . 8. The output of the generator supplies the current which … a motor.

III. Переведите текст. Most practical d.c. generators have electromagnetic fields. To produce a constant field to use in a generator, the field coils must be connected across a d.c. voltage source. The d.c. current in the field coils is called the «excitation current», and may be supplied either from a separate d.c. voltage source, or by using the d.c. output of the generator itself. If the field is supplied with current from an external source, the generator is called «separately excited»; but if some of the generator output is used to supply the field current it is said to be «self-excited». In a self-excited generator the field coils may be connected either in series with the armature coils («series»), in parallel with the armature coils («shunt»), or partly in series and partly in parallel with the armature coils («compound»). Separately-excited d.c. generators have two circuits: the field circuit, consisting of the field coils connected across a separate d.c. source, and the armature circuit, consisting of the armature coil and the load resistance. In a separately excited d.c. generator, the field is independent of the armature, since it is supplied with the current from either another generator (exciter), an amplifier or a battery. The separately-excited field provides a means of controlling the power output of the generator. With a slight change in the field current, a large change in the load current will result. A separately-excited generator is frequently used in automatic motor control systems. In these systems the field current is controlled by an amplifier, and the output of the generator supplies the current which drives a motor. 

IV. Ответьте на вопросы. 1. What is the d.c. in the field coils called? 2. What kind of a generator is supplied with the current from an external source? 3. What is a self-excited generator? 4. How can the field coils in a self-excited generator be connected? 5. How many circuits do separately-excited generators have? 6. Is the field in a separately excited d.c. generator independent of the armature? Why? 7. What kind of a device is the field current in a separately-excited generator controlled by?

V. Задайте вопросы к выделенным словам. 1. Ammeter measures the current flowing in a circuit. 2. Voltmeter is used to measure the potential difference between two points in a circuit. 3. The function of a wattmeter is to measure the power which is the product of the current and voltage. 4. We measure insulation resistance with a megohmmeter. 5. This device is easy to handle.

VI. Переведите предложения на английский язык. 1. Существуют два способа возбуждения генераторов. 2. В зависимости от способа возбуждения генераторы делятся на два типа: генераторы независимого возбуждения и генераторы с самовозбуждением. 3. Постоянный ток в катушках возбуждения называется током возбуждения. 4. Генераторы независимого возбуждения используют внешний источник для подачи тока возбуждения полю. 5. Генераторы с самовозбуждением используют часть своей выходной мощности для подачи тока возбуждения полю. 6. Самовозбуждение генераторов может быть последовательным, параллельным и смешанным. 7. Генераторы с независимым возбуждением имеют две цепи: цепь возбуждения (поля) и якорную цепь. 8. Небольшое изменение в токе возбуждения приводит к большому изменению в токе нагрузки.

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Вариант 2

I. Переведите следующие слова и словосочетания на русский или английский языки соответственно. Actuate, требующий большого пускового крутящего момента, automatic control system, неподвижная часть, rotating part, отделяются, air gap, служит для, commutator, обмотка, медная пластина, is attached to the shaft, посредством металлических колец, prime mover, питающая цепь, this may result in fluctuations, чтобы предотвратить эти дефекты.

II. Закончите предложения, используя информацию текста, приведённого ниже. 1. In order to prevent short circuits the armature of a motor and its stator are …. 2. In order to prevent fluctuations …. 3. A prime mover actuates …. 4. The function of a stator is … . 5. No current passes through an … .

III. Прочитайте и переведите текст. DIRECT CURRENT MOTORS D.c. motors actuate installations requiring large starting torques. To them belong, for example, electrified transport (electric trains, trolleybuses, etc.), cranes and other installations. D.c. motors are also used in automatic control systems. A d.c. motor consists of two main parts: stationary part (stator) and rotating part (rotor). These parts are separated by an air gap. The stator serves for producing the magnetic field. It includes the poles and a frame manufactured from iron and steel. The rotor (armature) comprises a shaft, a core, a commutator and windings. The windings is made of coil sections consisting of insulated copper wire. The commutator includes copper bars insulated from one another. The bars are also insulated from the shaft. The commutator is attached to the shaft by means of metal rings. The armature connected to the load is actuated by a prime mover. The prime mover supplies a torque. 36 When a motor is operating at no-load, the armature current is equal to zero or so small that it can be ignored. In direct connection of a d.c. motor to a supply circuit the starting current is rather heavy; it may exceed the rated value. This may result in fluctuations in the voltage or some other faults. In order to prevent these faults, d.c. motors should not be connected directly to the line voltage. In order to reduce high starting currents, starting rheostats should be applied.

IV. Согласитесь или опровергните следующие утверждения (true – false). 1. D. c. motors actuate installations requiring small starting torques. 2. Stationary and rotating parts in d.c. motor are joined by an air gap. 3. High starting currents are reduced by applying starting rheostats. 4. The armature consists of copper bars insulated from one another. 5. The prime mover is a device for supplying a torque.

V. Просмотрите слова и словосочетания, приведённые ниже, и расположите их в 2 столбца. В первый поместите все, относящиеся к частям двигателя постоянного тока, а во второй – названия устройств, в которых применяется этот двигатель. Переведите на русский язык. Insulated copper wire, shaft, fan, pump, commutator, metal ring, winch, windlass, capstan, core, winding, automatic control system, crane, electrified transport, field coils.

VI. Переведите на русский и английский языки соответственно. Direct current motors are of three principle kinds and are named according to the way their field coils are connected to the armature. They are named respectively: series, shunt and compound. In series motors the field windings and armature are connected in series with each other. Катушки возбуждения в двигателе с параллельным возбуждением соединены напрямую через щётки, поэтому двигатель получает полное напряжение сети, к которой он подключен. Двигатель с параллельным возбуждением можно назвать двигателем с постоянной скоростью.