II. Read and translate the text.

Electric power is generated by converting heat, light, chemical energy, or mechanical energy to electrical energy. Most electrical energy is produced in large power stations by the conversion of mechanical energy or heat. The mechanical energy of falling water is used to drive turbine generators in hydroelectric stations. The heat derived by burning coal, oil, or other fossil fuels is used to operate steam turbines or internal-combustion engines that drive electric generators. Also the heat from fissioning of uranium or plutonium is used to generate steam for the turbine generator in a nuclear power plant.

Electricity generated by the conversion of light or chemical energy is used mainly for portable power sources. For example, a photoelectric cell converts the energy from light to electrical energy for operating the exposure meter in a camera. A lead-acid battery converts chemical energy to electrical energy for starting an automobile engine.

Electric power produced in large power stations generally is transmitted by using an alternating current that reverses direction 25, 50, or 60 times per second. The basic unit for measuring electric power is the watt.

Electricity is clean, inexpensive, and easily transmitted over long distances. It is used to operate lights, pumps, elevators, power tools, furnaces, refrigerators, air-conditioners, radios, television-sets, industrial machinery, and many other kinds of equipment. It has been counted that in developed countries about 43% of the electric power is generally used for industrial purposes, 32% in homes, and 21% in commercial enterprises.

Vocabulary

III. Remember these words:

fossil, fuel, engine, steam, cell, reverse, to measure, equipment, fission, pump.

Grammar

IV. Translate these sentences. Find predicates in the passive voice.

A)

1. The transmission lines are interconnected in switching stations.

2. The first central electric power station was installed in 1882.

3. The world power capacity is doubled about per decade.

4. The cable will be used to test the transmission line.

5. These stations can be linked up into a network.

B)

1. Electrical loads or consumers in power installations are the various arrangements and installations that are used to transform electric power into mechanical, heat and chemical power, or energy.

2. In a power network the large blocks of electric power are transmitted on the grid of transmission lines. From the grid power is being subdivided into smaller blocks and fed into the transmission parts of the power network. Finally, the consumers are being serviced from the distribution network.

Date: 2015-12-11; view: 1474