2. Compare the two types of current.

   	Voltage	In houses	Battery appliance	Need of high voltage
   Direct Current
   Alternating Current

3. L ook at the pictures and describe them.

Power station

Steps up the voltage to 345 000 V

So it can be transferred through power line

Area Substation

Why not transfer electricity at a billion volts?

1) Air is not a perfect insulator;

2) At very high voltages arcs of “lightning” would shoot between power lines and the ground;

3) Safety. (Note: birds can land on a bare wire because they don’t create a closed circuit)

Steps the voltage down to 100 000 V

Steps the voltage down to 20 000 V

Distibuting Substation

4. Draw the scheme of distribution and delivery of electrical current to consumers.

5. Read the text eectrical generator

In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy usually via electromagnetic induction. Electromagnetic induction works by forcibly moving a loop of wire (a rotor) around a stationary bar (a stator) that provides an electric field, either through a permanent magnet or an electromagnet. By Faraday's law, this induces a current in the rotor, which can be used to power machinery or charge batteries. A generator forces electric current to flow through an external circuit. The source of mechanical energy may be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air, or any other source of mechanical energy. Generators provide nearly all of the power for electric power grids.

The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators have many similarities. Many motors can be mechanically driven to generate electricity and frequently make acceptable generators.

The electrical generator was first invented by the Hungarian inventor and engineer Anyos Jedlik between 1827 and 1830. Jedlik invented the generator, a simple dynamo, at least six years before Warner von Siemens in Germany and Charles Wheatstone in Britain, whose names are usually associated with the device's invention. Though the electrical generator was invented around 1830, it wouldn't be until Nikola Tesla's pioneering work on rotating magnetic fields around 1882 that generators would become suitable for industrial use.

An electric generator or electric motor that uses field coils rather than permanent magnets requires a current to be present in the field coils for the device to be able to work. If the field coils are not powered, the rotor in a generator can spin without producing any usable electrical energy, while the rotor of a motor may not spin at all.

The field coils are connected in series or parallel with the armature winding. When the generator first starts to turn, the small amount of remanent magnetism present in the iron core provides a magnetic field to get it started, generating a small current in the armature. This flows through the field coils, creating a larger magnetic field which generates a larger armature current.

Very large power station generators often utilize a separate smaller generator to excite the field coils of the larger.

Three Gorges Dam in China

Today, there exist electrical generators of all imaginable sizes, from 3-6 watt generators to power bicycle lights to the hydroelectric generators in the , which will provide 22.5 gigawatts of power when they are fully installed in 2012. The current worldwide production of electricity is about 20,000 terawatt-hours, with about 66% generated through thermal (burning of fossil fuels), 16% through hydro, 15% through nuclear, and 2% through renewables such as wind or solar power. For environmental and health reasons, worldwide efforts are underway to expand electrical production from hydro, nuclear, and renewable sources and reduce electrical production from fossil fuel sources.

a) Find in the text the English equivalents for Russian words.

1. поступательно-вращательный 8. подходящий 15. сокращать

2. горение твёрдого топлива 9. сходство 16. природоохранный

3. установленный 10. заставлять 17. возбуждать

4. вращаюшееся магнитное поле 11. рукоятка 18. вращаться

5. энергия солнца и ветра 12. сети 19. корпус

6. устройство 13. ядерный 20. железный стержень

7. превращать 14. возобновляемый 21. катушка магнитного

поля

b) Make up the sentences out of the given words.

1. electrical, mechanical, converts, energy, into, energy, A generator.

2. principles, on, generators, electrostatic, First, operated.

3. Michael, In, discovered, 1832,  Faraday, of, the principle, generators, electromagnetic.

4. hydraulic, Hydro- generator, turbine, is, by, a, driven.

5. fuels, Today, mainly, generated, is, from, burning, electricity.

c) Translate the word conbinations.

Генератор постоянного тока, возбуждение постоянными магнитами, магнитное поле, преобразовать в электрическую энергию, три подвижных магнита и шесть катушек, для увеличения мощности, возобновляемые источники энергии, неподвижный корпус, заряжать батарею, установить генератор переменного тока, заставить железный стержень вращаться, ядерная электростанция, понижающая и повышающая подстанции, очень высокое напряжение, распределение и потребление энергии.

d) Answer the questions.

1) What will happen if one bulb burns out in a series circuit? Why?

2) What are the main safety rules when you want to repair a socket?

3) What is necessary to force the generator to produce electrical current?

4) What is the difference between AC and DC?

5) How electrical current is delivered to consumers?

6) What are the two main types of circuit connections?

7) What electrical measuring instruments are used to work with electricity?

8) What causes the electrical shock?

e) The engineer is in the lab. Describe his duties at work using the following word combinations.

To work with, to test, to measure, to connect, to watch the indications, to check the type of the current, to turn on a switcher, insulated.