Power installations of construction machinery

A power installation is a complex consisting of an engine and its servicing systems. It converts some kind of energy into mechanical work. Engines are machines which change heat into motion. Depending on the type of engine, power installations employed in present- day construction machinery, in tractors and trucks can be subdivided into the following groups: steam, internal- combustion, electric, pneumatic and hydraulic ones.

Steam engines and internal- combustion engines are prime movers. They transform energy taken from fuel into mechanical work. Electric, pneumatic and hydraulic engines are known as secondary movers. They convert into mechanical work the energy produced by generators.

Internal combustion engines are the principal power installations employed in mobile and self propelled construction machinery as well as in trucks and tractors. They are very efficient under all working conditions and do not depend on the external sources of energy.

Electric power installations incorporate generators transforming mechanical energy into electrical one. The latter is then used to drive electric motors.

The widespread use of electric drives in road making and construction machines is due to their considerable economical and operational advantages as compared to other types of drives.

Pneumatic and hydraulic power installations are employed for machine control systems, auxiliary devices and mechanical tools.

Vocabulary:

power installation ['pQuq "Instq'leISqn] – силовая установка

engine ['enGIn] n.– двигатель

servicе ['sWvIs] v.– обслуживать

convert [kqn'vWt] v.– превращать

machine [mq'SJn] n.– машина, механизм

heat [hJt] n.– теплота

steam [stJm] n.– пар

internal- combustion [In't´nl kqm'bAsCqn] – внутреннее сгорание

pneumatic [njH'mxtIk] a.– пневматический

hydraulic [hQI'drLlIk] a. – гидравлический

source [s²s] n.– источник

generator ['GenqreItq] n.– генератор, источник энергии

auxiliary [Lg'zIljqrI] a. – вспомогательный

Answer the following questions:

1. What is a power installation?

2. What is the main function of a power installation?

3. What groups of power installations are there?

4. Why are steam engines and internal- combustion engines called prime movers?

5. How do the secondary movers work?

6. Why are internal- combustion engines the principal power installations in modern construction machinery?

7. What is the widespread use of electric drives in road making and construction machines due to?

8. What are pneumatic and hydraulic power installations employed for?

Э, М, ИНН, ПО (II семестр)

Date: 2015-10-19; view: 518; Нарушение авторских прав