motor generator

from The Century Dictionary.

• noun In electricity, an apparatus which changes one form of electrical power into another by means of two separate machines, a motor and a generator, permanently connected together. See converter, 3, dynamotor, and motor- generator.

from the GNU version of the Collaborative International Dictionary of English.

• The combination consisting of a generator and a driving motor mechanically connected, usually on a common bedplate and with the two shafts directly coupled or combined into a single shaft.