Railway Electrification

Unit 3

Ex.9. Make up a brief oral presentation about electrical current or circuit, electrical devices or measurements. Get information from units 1-2 or any other source.

Ex.8. Make up sentences using attributive groups from ex.7. according to the Model.

Ex.7. Read and translate the following attributive groups.

Ex.5. Read the course description. Then mark the following statements as true (T) or false (F). Correct the false statements.

1. The first section covers electrical measurements.

2. Safety techniques are taught in Basic Electricity II.

3. The second section is devoted to home electric appliances.

4. Students are supposed to make experiments at the end of the course.

5. Students can get a Certificate of Attendance upon the course completion.

6. Completion of the course is required for many jobs.

Ex. 6. Answer the questions after you have read the text:

7. Who is the course required for?

8. What does the course focus on?

9. How many parts are there in the course?

10. What is the first section about?

11. What can students learn about in the second section?

12. What knowledge can students gain from the third section?

13. How do students demonstrate what they have learned during the course?

Electrical circuit main elements, electrical circuit auxiliary elements, transmission line loads, electrical energy conversion, multiwinding transformer operation, electromagnetic process description, active and passive circuit elements, power station electricity supply, electrical appliance functioning, job safety techniques, measurement terminology studies.

Model: Measurement terminology studies are required for teaching qualified specialists.

Attributive group

are taught /required / explained is described /used / generated can be found / measured

at special courses; in electrical circuits; to change the type of energy; for home electrical appliances; at power stations, in a course book

Use the following phrases:

I would like to tell you about…/ I’m going to tell you about…/ My oral presentation is about / I will speak about…

First of all / Secondly / Then / Next / After that / And finally …

Let’s consider / discuss …/ In addition to this, I’d like to say…

I will explain / describe / present…

It is important to know that…/ It is useful to learn that…/ It’s worth mentioning that…

It is interesting to notice that… / In my opinion …

At the end I would like to…/ Finally I’ll say that…/ In conclusion I’d like to…

Thank you for your time.

If you have any questions, please, feel free to ask them. / I’ll be glad to answer your questions.

Railway must operate at variable speeds using different electrification systems such as AC (alternating current) and DC (direct current).

DC is a constant flow of electricity which travels around a circuit in one direction.

Unlike a DC supply, an AC supply flows backwards and forwards: its direction continually alternates. The rate at which the current alternates, called the frequency, is measured in hertz (Hz). For example, in the UK, AC supply is 50 Hz: it alternates 50 times per second.

Electricity supply is generated at power stations, which use large generators. A generator converts mechanical energy into electrical energy. Current from the generators leaves the power station and enters the power grid – the network of power lines (cables) which transmits it around the country.

DC voltages between 600V and 800V are used by most tramways (streetcars), trolleybus networks and underground (subway) systems. The DC system is quiet simple but it requires thick cables and short distances between feeder stations.

3kV DC is used in Belgium, Italy, Spain, Poland, Czech Republic, Slovakia, Slovenia, Croatia, South Africa and former Soviet Union countries.

DC is also used in third-rail systems. Third rail is applied in small-diameter tunnels and subway systems. There is also a four-rail system, which is used in the London underground.

AC is only used on overhead wires, as it implies very high voltages. Inside the locomotive, the transformer steps the voltage down for use by traction motors.

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