A starter/generator arrangement includes a starter/generator, a power converter electrically connected to the starter/generator, and coolant circuit with a pump and a condenser in fluid communication with the power converter. The power converter is arranged to flow start mode electrical power in a first direction in a start mode and a second direction in a generate mode. The coolant circuit fluidly couples the pump to the condenser for storing heat in a coolant disposed within the coolant circuit while flowing the start mode electrical power in the first direction. Gas turbine engines and methods of cooling starter/generator arrangements are also described.

The rapid assistance device applies to a free turbine engine of an aircraft having at least a first free turbine engine provided with a gas generator and associated with an electrical machine capable of operating both as a starter and as a generator, the first engine being capable of being put into a standby mode or into an unwanted shut-down mode, the electrical machine being powered from on on-board electrical energy power supply network. The device further includes at least one electrical energy storage member adapted to be electrically connected to the electrical machine associated with the first engine in order to provide a burst of assistance to the gas generator of that engine. The electrical energy storage member constitutes a non-rechargeable “primary” energy storage member that can be used once only. The device includes a system for activating the electrical energy storage member and a device for coupling the electrical energy storage member with an electrical power supply system of the electrical machine.

The rapid assistance device applies to a free turbine engine of an aircraft having at least a first free turbine engine provided with a gas generator and associated with an electrical machine capable of operating both as a starter and as a generator, the first engine being capable of being put into a standby mode or into an unwanted shut-down mode, the electrical machine being powered from on on-board electrical energy power supply network. The device further includes at least one electrical energy storage member adapted to be electrically connected to the electrical machine associated with the first engine in order to provide a burst of assistance to the gas generator of that engine. The electrical energy storage member constitutes a non-rechargeable “primary” energy storage member that can be used once only. The device includes a system for activating the electrical energy storage member and a device for coupling the electrical energy storage member with an electrical power supply system of the electrical machine.

A turbine system includes a compressor system compressing a fluid, a combustor system fluidly coupled to the compressor to combust a fuel mixed with the fluid to produce a combusted fluid, a gas turbine system fluidly coupled to the combustor to rotate a gas turbine shaft based on the combusted fluid, a power turbine system fluidly coupled to the gas turbine to rotate a power turbine shaft based on the combusted fluid existing the gas turbine, the shaft mechanically coupled to a clutch system, a clutch system mechanically coupled to a generator shaft, and an electric generator having the generator shaft to produce electricity based on rotations of the generator shaft. The turbine system includes a controller operatively coupled to the clutch system to restart production of the electricity via the clutch system.

A turbine system includes a compressor system compressing a fluid, a combustor system fluidly coupled to the compressor to combust a fuel mixed with the fluid to produce a combusted fluid, a gas turbine system fluidly coupled to the combustor to rotate a gas turbine shaft based on the combusted fluid, a power turbine system fluidly coupled to the gas turbine to rotate a power turbine shaft based on the combusted fluid existing the gas turbine, the shaft mechanically coupled to a clutch system, a clutch system mechanically coupled to a generator shaft, and an electric generator having the generator shaft to produce electricity based on rotations of the generator shaft. The turbine system includes a controller operatively coupled to the clutch system to restart production of the electricity via the clutch system.

An apparatus for driving a load is provided. The apparatus comprises a multiple-shaft gas turbine comprising a high pressure compressor and a high pressure turbine drivingly connected to one another by a first gas turbine shaft and a low pressure compressor and a power turbine drivingly connected to one another by a second gas turbine shaft extending coaxial with the first gas turbine shaft, the high pressure compressor and the high pressure turbine. The apparatus also comprises a load coupling drivingly connecting the power turbine to the load and a dual-speed turning gear with an output shaft drivingly engageable to and disengageable from the load, the dual-speed turning gear comprising a low speed turning motor and a high speed turning motor, wherein the low speed turning motor and the high speed turning motor are configured to selectively drive the load.

An apparatus for driving a load is provided. The apparatus comprises a multiple-shaft gas turbine comprising a high pressure compressor and a high pressure turbine drivingly connected to one another by a first gas turbine shaft and a low pressure compressor and a power turbine drivingly connected to one another by a second gas turbine shaft extending coaxial with the first gas turbine shaft, the high pressure compressor and the high pressure turbine. The apparatus also comprises a load coupling drivingly connecting the power turbine to the load and a dual-speed turning gear with an output shaft drivingly engageable to and disengageable from the load, the dual-speed turning gear comprising a low speed turning motor and a high speed turning motor, wherein the low speed turning motor and the high speed turning motor are configured to selectively drive the load.

A propulsion unit, notably for an aircraft, including a turbomachine; a propeller that can be selectively coupled to the turbomachine; a rotary electrical machine able to drive at least the turbomachine, and selective coupling of the rotary electric machine to the propeller and/or the turbomachine that is able to couple only the propeller to the rotary electrical machine during a defined stage of operation of the propulsion unit and that is able to couple or not couple the rotary electric machine to a gas generator and/or a free turbine of the turbomachine.

A propulsion unit, notably for an aircraft, including a turbomachine; a propeller that can be selectively coupled to the turbomachine; a rotary electrical machine able to drive at least the turbomachine, and selective coupling of the rotary electric machine to the propeller and/or the turbomachine that is able to couple only the propeller to the rotary electrical machine during a defined stage of operation of the propulsion unit and that is able to couple or not couple the rotary electric machine to a gas generator and/or a free turbine of the turbomachine.

A method of starting an aircraft having at least a first starter/generator (S/G) and a second S/G using at least one inverter/converter and at least one of an AC power source and a first DC power source, the method includes selectively starting at least one of the first S/G or second S/G in an AC start mode and in a DC start mode.