Abstract :
SINCE 1932, 60-cycle a-c systems have been used in most naval ship´s service electrical installations, particularly installations of large capacity. These systems operated satisfactorily and served well during World War II. However, during and since that period the trend has been to increase the use of electric power, thereby increasing weight and space requirements of the electric plant out of proportion to the size of the ship, and to require improved performance of the equipment installed. In order to solve this problem, consideration must be given to the basic factors influencing electric equipment designs. For example, an increase in system frequency increases maximum speed of rotation, thereby decreasing the weight of rotating electric machinery. In addition, high-frequency transformers and reactors require a lower value of maximum flux and, hence, a smaller iron core than corresponding 60-cycle units. Inherently smaller time constants permit increased speed of response, an advantage in certain control systems.
