3. Give the Russian equivalents of the following expressions.

To vary in size, according to the rated voltage, strung on a pole, strike a happy combination, mechanical weakness, as a practical conductor, touchstone of conductors, to determine their economical value, in particular circumstances;

medium – hard drawn, transmission circuit of long spans, springiness and flexibility, for tying conductors to pin – type insulator, soft – drawn wire, be limited to short spans;

short distribution spans, steel reinforced aluminum wire, transmission lines, to strand on a core of a wire, to rust rapidly, can be counteracted by galvanizing, lack of conductivity and durability, copper – clad and aluminum – clad steel wire, utility company, coating of copper, for guying purposes.

4. Find English equivalents of the following sentences in the text.

1. Существуют другие проводники кроме медных и алюминиевых, но они, к сожалению, являются плохими проводниками.

2. Для предотвращения процесса ржавления стальных проводников используется гальванизирование поверхности цинком.

3. Линейные проводники варьируются согласно номинальному напряжению.

4. Серебро из-за высокой стоимости и свойству легко подвергаться механическим воздействиям является нерентабельным проводником.

5. Алюминиевые проводники, армированные железом, очень прочные и чаще всего используются для длинных расстояний между опорами.

5. Answer the questions.

1. What materials are overhead line conductors generally made of?

2. What characteristics determine a conductor’s value?

3. What are advantages of aluminum as a conductor?

4. What are advantages of steel as a conductor?

5. Why are conductors stranded?

6. Retell the text ‘Conductors’ using the following word combinations.

The text deals ……………… .

It is arranged as follows ……………… .

The first paragraph introduces ……………… .

The second paragraph advances the idea of ……………… .

In conclusion ……………… is given.

Unit 7 (part 4). Conductors and insulators

1. Words to remember.

covering – изоляция

bare – неизолированный

resistant to abrasion – устойчивый к истиранию, износу

rubber gloves – резиновые перчатки

energized – под напряжением

bucket – подъёмная клеть, люлька

live conductor – неизолированный провод

groove – желоб

tie-wire – вязальная проволока

to hold by clamp or ‘shoe’ – удерживать зажимом или ‘башмаком’

to be spliced by overlapping and twisting the ends – соединенный / состыкованный с помощью наложения и скручивания концов

double sleeve – рукав

butt – торец

to crimp – сгибать

be gripped by a spring – зажимать пружиной

split-nut – разъёмная гайка

tin-plated bolt – болт с гальваническим покрытием

channel – желоб, паз

2. Read the text. Conductor coverings and connectors

CONDUCTOR COVERINGS

Conductors on overhead lines may be either bare or covered. Such conductors, located in trees, or adjacent to structures where they may come into occasional contact, may be covered with high density polyethylene or other plastic material resistant to abrasion. This covering is generally not sufficient to withstand the rated voltage at which the line is operating; so these conductors must be mounted on insulators anyway. The purpose of the covering is mainly to protect the wire from mechanical damage. The wires should be treated as though they were bare.

Whether or not the lines are covered, workers consider it necessary for safety to work with rubber. Besides wearing rubber gloves and sleeves, they make sure to cover the conductors, insulators, and other apparatus with line hose, hoods, blankets, and shields. Developments now allow workers to work on conductors while energized, as long as the platform or bucket in which they are standing is insulated. In this ‘bare hand’ method, they usually wear noninsulating leather work gloves. Extreme caution is necessary in this method, as the insulated platform or bucket insulates workers from a live conductor and ground, but does not protect them when working on two or more live conductors between which high voltage may exist. Transmission lines, operating at higher voltages, may be worked on when energized or de-energized. They are generally situated in open areas where the danger to the public from fallen wires is negligible. Also, because the amount of insulation required would make the conductor bulky and awkward to install, it is desirable to leave high-voltage transmission line conductors bare.

TIE WIRES

Conductors must be held firmly in place on the insulators to keep them from falling or slipping. On pin insulators, they are usually tied to the top or side groove of the insulator by means of a piece of wire, called a tie-wire. On suspension type insulators, conductors are usually held in place by a clamp or ‘shoe’. Where conductors must be maintained while energized, and cannot be touched by hands, they are handled on the ends of sticks called ‘hot sticks.’

CONNECTORS

Conductors are sometimes spliced by overlapping the ends and twisting the ends together, taking three or four turns. But to insure a good electrical connection as well as uniformity in workmanship, it is ends of the tie wires are looped so that they can be easily wrapped or unwrapped wise to connect conductors with mechanical connectors. They are often substantial money savers.

One type inserts the two ends into a double sleeve. When the two conductors are parallel and adjacent to each other, the sleeve is then twisted. With the compression sleeve the conductors are inserted from both ends until they butt and the sleeve is then crimped in several places. The ‘automatic’ splice has the conductor ends inserted in each end where they are gripped together by a spring. The split-nut connector is a copper or tin-plated bolt with a channel cut into the shank; both conductors fit into the channel and are compressed together by a nut.