Device for a continuous mechanical drive, in particular of a pump

The drive device has a coupling (4) for selectively connecting an internal combustion engine (2) with output shaft (1) between the engine and electrical machine (3). A flywheel (10) is provided between output shaft and coupling, which is supported on common drive shaft (8) of electrical machine. The electrical machine is used as a generator to output power to an uninterrupted electrical power supply when driving the output shaft to the engine. The electrical machine is designed as a synchronous machine.