VIII Speak about the function of three phase ac generator using the figure 1.1.

IX Find more information about the topic and prepare a presentation.

UNIT 7BRUSH-TYPE AC GENERATOR

AIM OF THE UNIT:- to identify brush-type ac generator

TASKS

1 Do your best to answer the brainstorming questions. 2 Read the text for general understanding.

3 Make up questions to the text. 4 Find the sentences with the new words in the text. Give the Kazakh or Russian

equivalents of the words.

5 Write sentences with the new vocabulary. 6 Do the given exercisesfor better remembering the tеxt.7Speak on the topic. Given schemes will help you to remember and understand the

topic.

8 Get more information about the topic. Do some research, create slideshow or a

project work and present them.

Brainstorming questions

 

 

1 What is a brush-typeac generatorconsists of?

2 What is the function of the brush-typeac generator?

 

A brush-typeac generator consists of an ac generator and a smallerdc exciter generator as one unit. The output of thegenerator supplies ac to the load. The only purpose forthe dc exciter generator is to supply the direct currentrequired to maintain the ac generator field.

The exciter is a dc, shunt-wound, self-excitedgenerator. The exciter field creates an area ofintense magnetic flux between its poles. When theexciter armature rotates in the exciter-field flux,voltage is induced in the exciter armature windings.The output from the exciter commutator flowsthrough brushes and slip rings to the generator field.

Being dc, already converted by the exciter commutator,the current always flows in one direction through thegenerator field. Thus, a fixed-polarity magneticfield is maintained in the generator field windings.

When the field winding rotates, its magnetic flux passesthrough and across the generator armature windings. The ac in the ac generator armature windings flowsthrough fixed terminals to the ac load.

The stationary member of the generator consists ofthe ac armature and the dc exciter field. Both ac andexciter terminal boards are easily accessible. All brushrigging is on the generator and has a brush cover. Theslotted-hole mounting provides for ease in attaching tothe engine pad. The capacitors connected between theexciter armature terminals and ground suppress radionoise.