Английский язык. Арланова Т.Л - 25 стр.

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Exercise 4. Study the diagram below of a portable generator. Answer these
questions using the diagram and your own knowledge of engineering.
What are its main parts?
What does the engine run on?
What are the four strokes called?
What is the function of the crankshaft?
What do both stator and rotor have?
What is the difference between stator and rotor?
Exercise 5. Read this text to check as many of the answers as you can.
You will not find complete answers to all of the questions.
Portable generator
Although most electricity comes from power stations, power can also be
generated by far smaller means. Nowadays, electricity generators can be
small enough to hold in the hand.
Portable generators are made up of two main parts: an engine, which
powers the equipment, and an alternator, which converts motion into
electricity.
The engine shown (Fig. 1) runs on petrol. It is started by pulling a cord.
This creates a spark inside which ignites the fuel mixture.
In a typical four-stroke engine, when the piston descends, the air inlet
valve opens and a mixture of air and petrol is sucked in through a carburettor.
The valve closes, the piston rises on the compression stroke and a spark
within the upper chamber ignites the mixture. This mini-explosion pushes
the piston back down, and as it rises again the fumes formed by the ignition
are forced out through the exhaust valve.
This cycle is repeated many times per second. The moving piston makes
the crankshaft rotate at great speed.
The crankshaft extends directly to an alternator, which consists of two
main sets of windings-coils of insulated copper wire wound closely around an
iron core. One set, called stator windings, is in a fixed position and shaped
like a broad ring. The other set, the armature windings, is wound on the rotor
which is fixed to the rotating crankshaft. The rotor makes about 3,000
revolutions per minute.
The rotor is magnetized and as it spins round, electricity is generated in
the stator windings through the process of electromagnetic induction. The
electric current is fed to the output terminals or sockets.
This type of generator can produce a 700 watt output, enough to operate
lights, television, and some domestic appliances. Larger versions provide
emergency power to hospitals and factories.
Source: Adapted from 'Inside out: Portable generator'. Education Guardian
Exercise 6. Study this text on the four-stroke cycle. Then label each stroke
correctly in Fig. 2 opposite.
In the four-stroke cycle, the piston descends on the intake stroke, during