Excitation systems for a.c. aircraft generators

The paper briefly reviews various methods of exciting a.c. aircraft generators and the control equipment associated with each, and discusses the requirements of reliability, endurance and light weight for modern aircraft. The limitations of various existing methods are discussed and it is shown that a.c. exciters offer the following advantages: (a) A minimum of sliding contacts and even their complete elimination if silicon rectifiers are mounted on the generator shaft. (b) Fewer machine cooling difficulties. (c) Use of transductors (magnetic amplifiers) for voltage control. (d) High margin for excitation under fault conditions, with more rapid excitation response as a result.