Study of transformerless rectified higher voltage D-C aircraft electric system

Variable-frequency a-c systems and paralleled d-c supplies operating simultaneously from the same a-c generators and with the elimination of transformers, voltage regulators, and reverse-current relays from the d-c supplies are proposed as a means of increasing aircraft reliability and of reducing costs, complexity, and weight. The suggested system can be connected to provide either a single direct voltage or two direct voltages obtained without transformers and without interfering with the simultaneous use of the a-c generators for conventional variable-frequency a-c loads.