PURPOSE: To improve the quality of the generated electricity by connecting a generator and two prime movers located on both sides so that the rotor section of the generator is made the node of the shaft system torsional vibration and the shaft rotary phases of the prime movers can be adjusted.

CONSTITUTION: Two prime movers 1 and 1' are arranged on both sides of a generator 2, and they are connected via multiple drive sections 3 and 3' and couplings 4 and 4' respectively. The shaft rotary phases of the prime movers 1 and 1' are adjusted by moving bolts of the couplings 4 and 4' in bolt holes. The node (c) of the shaft system torsional vibration is located on the rotor section of the generator, and the driving torque of the rotor section can be reduced. The quality of the electricity fed by the generator 2 can be improved.