Simplified back-up VSCF converter systemUNIT 5 PERMANENT MAGNET GENERATORS
AIMS OF THE UNIT: - to describe permanent magnet generators
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 Make up exercises as in the UNIT 2page 210 (Exercises for better remembering the topic). 7 Speak on the topic. Given schemes will help you to remember and understand the topic. 8 Find more information about the topic and make up a project work on the topic.
1 What is the function of back-up generator? 2 What is PMA?
The use of PMGs to provide emergency power has become prominent over the last decade or so. As can be seen from the description of the back-up converter above, the back-up generator hosts PMGs which may supply several hundred watts of independent generated power to the flight control DC system where the necessary conversion to 28 VDC is undertaken. It was already explained earlier in the chapter that AC generators include a PMG to bootstrap the excitation system. PMGs – also called Permanent Magnet Alternators (PMAs) – are used to provide dual independent on-engine supplies to each lane of the FADEC. As an indication of future trends it can therefore be seen that on an aircraft such as the Boeing 777 there are a total of 13 PMGs/PMAs across the aircraft criticalcontrol systems – flight control, engine control andelectrical systems. Boeing 777 PMG/PMA complement
|
