Turbo Alternators set consists of a high-speed turbine coupled to a low speed electrical machine through a reduction gearbox. However, the power output of an electrical machine is proportional to speed. Consequently, if the electrical machine is run at turbine speed, it is so small that it can be integrated into the engine on the same shaft as the turbo machinery forming a compact high-speed generator or turbo alternator. The gearbox is no longer required and the alternator also acts as a starter motor to further reduce the size of the generator set.