A turbofan engine includes a first spool including a first turbine, and a first tower shaft engaged to the first spool. A second spool includes a second turbine, and a second tower shaft is engaged to the second spool. A superposition gearbox includes a sun gear, a plurality of intermediate gears engaged to the sun gear, and is supported in a carrier and a ring gear circumscribing the intermediate gears. The first tower shaft or the second tower shaft drives one of the intermediate gears. A drive motor is engaged to drive the sun gear, an inner electric motor, a stator disposed radially outside of the inner electric motor, and an outer electric motor disposed radially outside the stator. A first load on the first spool and a second load on the second spool is adjusted by operation of at least one of the inner electric motor and the outer electric motor.

A turbomachine for a vehicle is provided. The turbomachine includes a first rotatable component; a first power source operatively coupled with the first rotatable component; a second power source selectively coupled with the first rotatable component; and a controller having one or more processors and one or more memory devices, the one or more memory devices storing instructions that when executed by the one or more processors cause the one or more processors to perform operations, in performing the operations, the one or more processors are configured to: receive an input indicating an engine shutdown of the turbomachine; and in response to the engine shutdown, cause the second power source to provide power to and rotate the first rotatable component.

An aspect of the present disclosure is directed to a method for mitigating rotor bow in a turbo machine. The method includes rotating a rotor over a first period of time; discontinuing rotation of the rotor for a second period of time; and iterating, over an overall period of time, rotation of the rotor over the first period of time and discontinuing rotation of the rotor for the second period of time.

A turning system for rotating equipment, comprises a motor configured for speed control; a gear connected to the motor, the gear is further connected to the rotating equipment, the motor and gear are configured for rotating the rotating equipment at speeds less than the normal operating speed of the rotating equipment; and a controller configured to perform a method, wherein the method comprises a sequence of steps including, rotating the rotating equipment from a standstill an angular amount of rotation, stopping rotation after moving the angular amount of rotation, and maintaining the rotating equipment at a standstill for a period of time; and repeating the sequence of steps. By performing the sequence of steps after the rotating equipment comes to a standstill, bowing or sagging of the rotating equipment can be prevented, and the rotating equipment is ready to startup at anytime.

A method for starting a turbine engine in cold weather, including a starting system intended for rotating a drive shaft of the turbine engine. The method includes the following steps: a pre-starting step in which a first starting signal is generated to control the drive shaft in a first direction of rotation about a longitudinal axis and in a second opposite direction of rotation in an alternating manner; and a starting step in which a second starting signal is transmitted to the starting system in order for the latter to drive the drive shaft of the turbine engine in a normal direction of rotation and in which the drive shaft is rotated until a rotation speed that causes the turbine engine to start.

A method of manufacturing a motoring system for a gas turbine engine including the steps of: forming a mechanical shaft fuse, the mechanical shaft fuse including a plurality of through holes; forming an outer housing; installing a reduction gear train into the outer housing, the reduction gear train having an input and an output; operably connecting an electric motor to the input; operably connecting a clutch to the output using the mechanical shaft fuse, the clutch in operation engages and disengages the reduction gear train; operably connecting a starter to the clutch, the starter having an output shaft; and operably connecting an accessory gearbox to the output shaft of the starter. The mechanical shaft fuse in operation shears when torque on the mechanical is greater than or equal to a selected value.

A method of manufacturing a motoring system for a gas turbine engine including the steps of: forming a mechanical shaft fuse, the mechanical shaft fuse including a plurality of through holes; forming an outer housing; installing a reduction gear train into the outer housing, the reduction gear train having an input and an output; operably connecting an electric motor to the input; operably connecting a clutch to the output using the mechanical shaft fuse, the clutch in operation engages and disengages the reduction gear train; operably connecting a starter to the clutch, the starter having an output shaft; and operably connecting an accessory gearbox to the output shaft of the starter. The mechanical shaft fuse in operation shears when torque on the mechanical is greater than or equal to a selected value.

A wash system for a gas turbine engine includes a core turning assembly having a motor configured to be mechanically coupled to the gas turbine engine. The rotor of the core turning assembly is further configured to rotate one or more components of a compressor section or a turbine section of the gas turbine engine at a rotational speed greater than two (2) revolutions per minute and less than five hundred (500) revolutions per minute during washing operations of the gas turbine engine.

A wash system for a gas turbine engine includes a core turning assembly having a motor configured to be mechanically coupled to the gas turbine engine. The rotor of the core turning assembly is further configured to rotate one or more components of a compressor section or a turbine section of the gas turbine engine at a rotational speed greater than two (2) revolutions per minute and less than five hundred (500) revolutions per minute during washing operations of the gas turbine engine.

A turbofan engine includes a first spool including a first turbine, and a first tower shaft engaged to the first spool. A second spool includes a second turbine, and a second tower shaft is engaged to the second spool. A superposition gearbox includes a sun gear, a plurality of intermediate gears engaged to the sun gear, and is supported in a carrier and a ring gear circumscribing the intermediate gears. The first tower shaft or the second tower shaft drives one of the intermediate gears. A drive motor is engaged to drive the sun gear, an inner electric motor, a stator disposed radially outside of the inner electric motor, and an outer electric motor disposed radially outside the stator. A first load on the first spool and a second load on the second spool is adjusted by operation of at least one of the inner electric motor and the outer electric motor.