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.

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

To produce a constant field to use in a generator, the field coils …

across a d.c. voltage.

The d.c. current in the field coils … the «excitation current».

The excitation current … from a separate d.c. voltage.

A generator … part of its output to supply a field current.

Separately excited generators … two circuits.

In a separately excited d.c. generator the field … independent of the armature.

With a slight change in the field current, a large change in the load current … .

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.

Ответьте на вопросы.

What is the d.c. in the field coils called?

What kind of a generator is supplied with the current from an external source?

What is a self-excited generator?

How can the field coils in a self-excited generator be connected?

How many circuits do separately-excited generators have?

Is the field in a separately excited d.c. generator independent of the armature? Why?

What kind of a device is the field current in a separately-excited generator controlled by?

Задайте вопросы к выделенным словам.

Ammeter measures the current flowing in a circuit.

Voltmeter is used to measure the potential difference between two points in a circuit.

The function of a wattmeter is to measure the power which is the product of the current and voltage.

We measure insulation resistance with a megohmmeter.

This device is easy to handle.

Переведите предложения на английский язык.

Существуют два способа возбуждения генераторов.

В зависимости от способа возбуждения генераторы делятся на два типа: генераторы независимого возбуждения и генераторы с самовозбуждением.

Постоянный ток в катушках возбуждения называется током возбуждения.

Генераторы независимого возбуждения используют внешний источник для подачи тока возбуждения полю.

Генераторы с самовозбуждением используют часть своей выходной мощности для подачи тока возбуждения полю.

Самовозбуждение генераторов может быть последовательным, параллельным и смешанным.

Генераторы с независимым возбуждением имеют две цепи: цепь возбуждения (поля) и якорную цепь.

Небольшое изменение в токе возбуждения приводит к большому изменению в токе нагрузки.

 

 

Вариант 2

Переведите данные слова и словосочетания на русский язык.

Сircuit overload, fuse, excessive current, tripped position, to reset, live wiring, to melt a metal conductor, to restore power exposed, fuse clips, electrocution, to interrupt, selective tripping, to replace, protective covering.

Подставьте в предложения недостающие слова, воспользовавшись приведёнными в скобках подсказками.

(Перегруз цепи) is drawing too many amperes, which can result in damage to the electrical devices.

(Плавкий предохранитель) is a piece of metal with a low melting point, inserted in series with a circuit.

The circuit breaker is a safe device, since (электропроводка, находящаяся под напряжением), is behind the cover.

(Оголённые контактные пружины плавкого предохранителя) can cause electrocution if touched.

Circuit breakers are normally designed for (выборочного срабатывания).

III. Составьте предложения, используя слова, приведённые ниже.

a) automatically, an overload, is, each, circuit, protected, from.

b) fuses, stop, open, flow, circuit, circuit breakers, automatically, electricity, of.

c) can, reset, to, be, manually, position, circuit, the, «on», a, breaker.

d) to restore, the, fuse, replaced, in, power, be, order, must.

e) the, of, cause, should, overload, identified, circuit, be, the.

Переведите на русский язык следующий отрывок.

Each electrical circuit on the ship has a maximum current load, measured in amperes (amps) that it can safety handle. A circuit overload (drawing too many amps) will result in overheated wiring and damage to the electrical devices it serves. Therefore, each circuit is automatically

protected from an overload. On newer ships, this is done with circuit breakers. On older ships, the circuits are protected by fuses. Both devices automatically open the circuit and stop the flow of electricity when they are heated by excessive current. A circuit breaker moves to the

tripped position and, after a few minutes to cool off, can be manually reset to the «on» position. The circuit breaker is also safe, since all live wiring is behind the cover. Fuses interrupt the flow of current by melting a metal conductor inside a protective covering. In order to restore

power, the fuse must be replaced. This must be done by qualified personnel only, as the exposed fuse clips can cause electrocution if touched.

A circuit breaker is a magnetic type overload relay designed to protect circuits not only from overload but from voltage failure or current reversal.

A fuse is simply a piece of metal with low melting point inserted in series with a circuit which is to be protected. Although a fuse is a simple and inexpensive device, it has the disadvantage that it is almost instantaneous in action. So a fuse cannot be used to protect motor as the starting

current is a lot higher than the operating current.

Восстановите недостающие реплики.

– How are circuits protected from an overload on your ship?

– ……

– How is the protection performed?

– ……

– Are fuses used on modern ships?

– ……

– What disadvantage does a fuse have?

– ……

Составьте вопросы, ответами на которые могли бы являться следующие предложения.

Exceeding the maximum values is called an overload.

An overload will result in overheated wiring and damage to the electrical devices.

Fuses are rated in amperes.

The proper fuse must be used for each circuit in order to afford proper overload protection.

The cause of the circuit overload should be identified and corrected before the circuit breaker is reset or the fuses replaced.

Circuit breakers are designed for selective tripping.

The circuit breakers closest to the fault should trip first.

Selective tripping ensures circuit protection while maintaining power to as much of the ship as possible.

A fuse cannot be used to protect motors because the starting current is much higher than the operating current.

Yes, a circuit breaker is a magnetic type overload relay

VII. Переведите на английский язык.

ЗАЩИТА ЦЕПИ ОТ ПЕРЕГРУЗКИ

На нашем судне цепи защищены от перегрузки с помощью автоматических выключателей. Обычно схема защиты состоит из автоматов, плавких предохранителей, контакторов, реле максимального тока (overcurrent relays), реле минимального напряжения (under-voltage relays) и реле обратной мощности (reverse power relays). Процесс защиты происходит следующим образом: автомат прерывает ток повреждения (fault current). Реле максимального тока обнаруживает ток повреждения и инициирует срабатывание.

Автоматический выключатель – это реле магнитного типа, предназначенное защищать цепи не только от перегрузок, но и от сбоев в напряжении и обратного тока (current reversal).