VII Prepare a presentation on the topic.

VIII Using the figures describe brushless type ac generators.

UNIT 9AC GENERATOR VOLTAGECONTROL

AIMS OF THE UNIT: - to identify alternatingcurrent (ac) generator

voltagecontrol

- to understand the grammar point ‘Gerund and

Participle I `

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 topic.7 Study grammar point ‘Gerund and participle I` do the tasks and sentences with

Gerund and participle I in the text.

8 Speak on the topic. Given schemes and questions will help you to remember and

understand the topic.

9 Find more information about the topic. Do some research, create slideshow or a

project work and present them.

Brainstorming questions

 

1 What is the most common method of voltage regulation for ac generators?

2 Why would we use a permanent magnet on the generator rotor in place of exciter

windings?

 

Methods of voltage regulation include varying thecurrent to the generator exciter windings andmaintaining a constant load on the generator. This isaccomplished by using a voltage regulator. Generator output frequency is regulated by keepingthe generator rotating at a required speed. This is doneby mounting the generator on a constant speed drive(CSD) unit.The most commonmethod of voltage control inpower generating systems is varying the current to thegenerator exciter winding (sometimes called fieldwinding). This, in turn, changes the size of themagnetic field, which changes the voltage output of thegenerator. The second method of voltage regulation is tomaintain a constant load on the generator. This methoduses a permanent magnet on the generator rotor in placeof exciter windings, which simplifies generatorconstruction. This type of regulation must be used withsystems that supply constant loads and have a limitedcapacity. For example, an inverter or an electronicpower supply uses this type of voltage regulation. Theregulator varies the resistance of a parallel resistor, sototal resistance remains constant regardless of the loadresistance. This typeregulator is for use with both acand direct current (dc) power sources.