Dynamotor

An electrical machine that converts low-voltage DC into high-voltage DC. The dynamotor has two armatures on its single rotating shaft, and these armatures turn inside of two sets of field coils. One set of field coils and one armature is for a low-voltage DC motor, and the other set of field coils and armature are for a high-voltage DC generator. A dynamotor is also called a rotary converter.