I. Before reading the text try to predict what information you will find in it, choosing the statements from the list below.
a. History and development of electric motors.
b. Operating principle of an electric motor.
c. Use of electric machines.
d. Nanotube nanomotor.
e. Motor standards.
II. Read the text to find out if you are right.
Vocabulary
reverse [rɪ'vɜ:s] – противоположный, обратный
alternator ['ɔ:ltəneɪtə] – генератор переменного тока
dynamo ['daɪnəməu] – динамо-машина
Traction motor – тяговый электродвигатель
vehicle ['vi:ɪkl] – транспортное средство
Disk drive – дисковод
grid – энергетическая система
inverter [ɪn'vɜ:tə] – инвертор, обратный преобразователь
propulsion [prə'pʌlʃən] – силовая установка
rating ['reɪtɪŋ] – (номинальная) мощность; производительность
exploitation [,eksplɔɪ'teɪʃən] – использование
solenoid ['səulənɔɪd] – соленоид
actuator ['æktʧueɪtə] – силовой привод
transducer[trænz'dju:sə] – преобразователь
Electric Motor
An electric motor is an electromechanical device that converts electrical energy into mechanical energy.
Most electric motors operate by interacting magnetic fields and current-carrying conductors to generate force. The reverse process, producing electrical energy from mechanical energy, is done by generators such as an alternator or a dynamo; some electric motors can also be used as generators, for example, a traction motor on a vehicle may perform both tasks. Electric motors and generators are commonly referred to as electric machines.
Electric motors are found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives. They may be powered by direct current, e.g., a battery powered portable device or motor vehicle, or by alternating current from a central electrical distribution grid or inverter. The smallest motors may be found in electric wristwatches. Medium-size motors of highly standardized dimensions and characteristics provide convenient mechanical power for industrial uses. The very largest electric motors are used for propulsion of ships, pipeline compressors, and water pumps with ratings in the millions of watts. Electric motors may be classified by the source of electric power, by their internal construction, by their application, or by the type of motion they give.
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The physical principle behind production of mechanical force by the interactions of an electric current and a magnetic field, Faraday's law of induction, was discovered by Michael Faraday in 1831. Electric motors of increasing efficiency were constructed from 1821 till the end of the 19-th century, but commercial exploitation of electric motors on a large scale required efficient electrical generators and electrical distribution networks. The first commercially successful DC motor was demonstrated in 1873 by Zenobe Gramme, a Belgian electrical engineer. The first AC motor was invented in 1888 by Nikola Tesla.
Some devices convert electricity into motion but do not generate usable mechanical power as a primary objective, and so are not generally referred to as electric motors. For example, magnetic solenoids and loudspeakers are usually described as actuators and transducers instead of motors.
III. Answer the following questions:
1. What is the work of an electric motor based on?
2. What is the difference between an electric motor and a generator?
3. How are electric motors used?
4. What types can electric motors be divided in?
5. Why is the name of M. Faraday associated with the invention of electric motors?
6. When was the first motor powered by alternating current made?
7. What appliances belong to transducers?
IV. Find in the text and put down 10–12 words or word combinations which can be used to speak about electric motors.
V. Find words with similar meanings.
To use, to demonstrate, appliance, to convert, grid, use, to apply, exploitation, to perform, force, different, instrument, diverse, device, to execute, network, tool, to transform, power, to show.
VI. Match the name of the device with its explanation.
battery, electricity, antenna, temperature, alternator, generator, thermometer, dynamo, adaptor, compass
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1. This makes electricity. 2. This shows North. 3. This stores electricity.
4. An AC _____ changes AC to DC. 5. This receives radio signals. 6.
A solar panel changes sunlight into _____. 7. You can measure _____ in Fahrenheit or Celsius. 8. This is an electric generator for producing AC.
9. This measures temperature. 10. This turns and makes electricity.
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