Patent ID: 8657566

Claim:
A turbine engine for a helicopter, comprising: a gas generator; a free turbine which is driven in rotation by a gas stream generated by the gas generator and which transmits rotary movement to a rotor of the helicopter, the free turbine being disposed downstream of the gas generator; a reversible electric machine including a shaft which is coupled to a shaft of the gas generator via a first deactivatable coupling device and which is coupled to a shaft of the free turbine via a second deactivatable coupling device, wherein the first deactivatable coupling device includes a first freewheel and a first stepdown gear having a first stepdown coefficient, wherein the second deactivatable coupling device includes a second freewheel, mounted in opposition of the first freewheel, and a second stepdown gear having a second stepdown coefficient, wherein, when the first deactivatable coupling device is activated during a stage of starting the turbine engine, rotation of the shaft of the reversible electric machine drives rotation of the shaft of the gas generator so that the reversible electric machine sets the gas generator into rotation, wherein, when the second deactivatable coupling device is activated after the turbine has started, rotation of the shaft of the free turbine drives rotation of the shaft of the reversible electric machine so that the reversible electric machine generates electricity, wherein, when the first deactivatable coupling device is deactivated, rotation of the shaft of the gas generator cannot drive rotation of the shaft of the reversible electric machine, wherein, when the second deactivatable coupling device is deactivated, rotation of the shaft of the reversible electric machine cannot drive rotation of the shaft of the free turbine, and wherein the first and second deactivatable coupling devices are not activated simultaneously.