Exciter polarity reversals in aircraft alternators

THE USE OF a-c generators in aircraft has posed some new problems. One of these is co-ordinating the excitation system design with the alternator design to obtain satisfactory performance during transient conditions. There has been much concern over the tendency of exciters to reverse polarity under the conditions of initial build-up, and when a short circuit is applied to the alternator. The tendency is most pronounced on wide-speed-range machines operating near their maximum speeds.