Say a few words about your electrical engineering laboratory. Are there any faulty devices in it? Have a talk with your groupmate about the faults and the ways to repair them

10. You know that all electrical devices and installations are constructed of a certain number of components. To these components belong elec­tric power sources, wires, cables, buses, switches, fuses, resistors, rheo- j stats, capacitors, transformers, motors and others.

Let us have a talk about these components. Speak with your group-] mates about their types, their use, operation, possible faults and ways of their repair. Use the table below:

Circuit components

Electric energy source

D.c. generator

D.c. motor

Chemical power source (primary or storage cell)

11. Draw schemes of circuits and devices constructed from these compo­nents. Have a talk with your groupmates about them:

1. Connect four resistors, two voltage sources and a switch in series. Speak about the construction and the operation of the circuit.

2. Connect several resistors and cells in series-parallel. Suppose that one of the resistors gets open; what does it result in? Suppose that a whole set gets open. What does it result in?

3. Measure the value of current (voltage, power, resistance) in the circuit. Use proper meters. Speak about the way you connect the meters to the circuit.

4. Take the proper components and construct an earthing protection sys­tem. Draw its scheme. Speak about its operation.

5. Draw a scheme of a thermal relay. What components are necessary for it?

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6. Draw a scheme of an overhead transmission line. Speak about its op­eration. What are its possible faults?

7. Draw a scheme of a substation. Speak about its operation and about its possible faults. What are the ways of their repair?

1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.

b) Cover the left column and translate the Russian words back into English.

[э'флг]

достигать

принадлежать, относиться (к)

снабжать, питать

определять

относиться (к), быть связанным (с)
[pn'dommant] преобладающий
[gra:f] кривая, график

народное хозяйство

2. Read the words and put down their Russian equivalents. Then trans­late them back into English (orally).

[.kaenkta'nstik]

[mju:'nisipl]

[I'lektnfai]

[[tiaidrou]

['piariad]

3. Distribute the words below into three columns:

actionprocessdoer

utilizer, protect, distribution, utilize, protection, distributor, consumption,! consume, utilization, consumer

4. Put down the Russian equivalents of these word combinations. Trans­
late them back into English (orally).

a. load graph_______________________________________

lighting load_______________________________________ J

power load________________________________________ .1

b. power utilizing devices parallelly operating plants enterprises utilizing power

5. Complete the sentences translating the words in brackets:

1. Water-turbine (заводы) are called hydroturbines.

2. Load graph (определяет) the operating load (условия).

3. Economical (потребление) of electric power (достигается) by inter­connected operation of power plants.

Electric Power Consumers and Power Systems

An electric power consumer is an enterprise utilizing electric power. Its operating characteristics vary during the hours of day, days and nights, days of week and seasons.

All electric power consumers are divided into groups with common load characteristics. To the first group belong municipal consumers with a predominant lighting load: dwelling houses, hospitals, theatres, street lighting systems, mines, etc.

To the second group belong industrial consumers with a predomi­nant power load (electric motors): industrial plants, mines, etc.

To the third group belongs transport, for example, electrified rail­ways. The fourth consists of agricultural consumers, for example, elec-trotractors.

The operating load conditions of each group are determined by the load graph. The load graph shows the consumption of power during dif­ferent periods of day, month, and year. On the load graph the time of the maximum loads and minimum loads is given.

Large industrial areas with cities are supplied from electric networks fed by electric power plants. These plants are interconnected for opera­tion in parallel and located in different parts of the given area. They may include some large thermal and hydroelectric power plants.

The sum total of the electric power plants, the networks that inter­connect them and the power utilizing devices of the consumers, is called a power system. All the components of a power system are inter­related by the common processes of protection, distribution, and con­sumption of both electric and heat power.

In a power system, all the parallelly operating plants carry the total bad of all the consumers supplied by the given system.

81 -

The building up of a power system is of great importance for the na. tional economy. An economical utilization of the power plant install*, tions and of the sources of power is achieved by interconnected operation of a series of power plants in a common power distribution system.

6. Answer these questions:

1. What enterprises are called electric power consumers?

2. When do their operating characteristics vary?

3. What consumers belong to the four different groups?

4. What conditions does the load graph determine?

5. What type of system is called a power system?

6. What processes interconnect the components of a power system?

7. In what way is an economical utilization of power installation? achieved?

7. Describe a power system and its operation.

1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.

b) Cover the left column and translate the Russian words back into English.

2. Put down the Russian equivalents of these word combinations. Trans­late them back into English (orally).

circuit breaker J

auxiliary units________________________________________ I

distribution centre

flexible construction_____________________________________

reliable operation_______________________________________

switch gear bus________________________________________

hydraulic as well as solar sources of energy_____________________

as to phase-word motors__________________________________

3. Fill in as well as, as to and translate the sentences:

1. Excessive starting current may result in fluctuations in the voltage ... in other faults of the motor.

2. ... A.C. motors they are subdivided into single- and three-phase motors.

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