Motor–generator

A motor–generator (an M–G set)is a device for converting electrical power to another form. Motor–generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line. Large motor–generators were widely used to convert industrial amounts of power while smaller motor–generators (such as the one shown in the picture) were used to convert battery power to higher DC voltages. These motor-generators should not be confused with "motor generator", which is a term occasionally used to describe a portable generator powered by an internal combustion engine.