Reading
Date: 2015-10-07; view: 431.
Tuning-in
Electricity generation
Unit 6
Task 9
Speaking
Apply, application, supply, efficient, efficiency, rate, available
Vocabulary Study
Put the following words in their proper forms into the blanks:
1. High internal resistivity of the material will reduce its …
2. Compressive forces must be … through spring-loading.
3. These materials are … today and are used for military… .
4. Small conventional power … have an … of 5%.
5. Present energy sources are unable to … our needs for electric power.
6. Today a thermoelectric generator … at 5,000 watts is available.
Speak on different ways of generating electricity
Generating electricity is a miracle of modern technology. Acting more or less like a force field, electric current is comprised of protons and electrons that become charged when induced by friction or chemical changes. Most power plants burn fuel - coal, oil, natural gas, biomass - which creates steam to drive a turbine that generates electricity. Sometimes nuclear or solar energy creates the steam to drive the turbine. Other technologies - such as solar photovoltaics or fuel cells - rely upon chemical reactions to generate electricity.
Task 1. List the different ways in which electricity can be generated
Task 2. Study the diagram below of a portable generator. Answer these questions using the diagram and your own knowledge of engineering.
1) What are its main parts?
2) What does the engine run on?
3) What are the four strokes called?
4) What is the function of a crankshaft?
5) What do both stator and rotor have?
6) What is the difference between stator and rotor?
A portable generator can provide electricity to power lights and other appliances no matter how far you are from the mains. It works by turning the movement of a piston into electrical energy.
Task 3. Read the text to check as many of the answers as you can. You will not find complete answers to all the questions.
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| Fig.6. Plot of efficiency vs. cathode temperature for a number of materials for thermionic generators under investigation at the Westinghouse research laboratories | | |