In some examples, a gas turbine engine including a high-pressure (HP) spool assembly including a HP shaft, a HP compressor and HP turbine; a lower pressure (LP) spool assembly including a LP shaft and LP turbine; a motor-generator coupled to the LP shaft; and a controller. The controller is configured to control the motor-generator to operate in a motor mode to apply torque the LP shaft during a starting of the HP spool assembly, and control the motor-generator to operate in a generator mode for a least a period of time following the starting of the HP spool assembly.

In some examples, a gas turbine engine including a high-pressure (HP) spool assembly including a HP shaft, a HP compressor and HP turbine; a lower pressure (LP) spool assembly including a LP shaft and LP turbine; a motor-generator coupled to the LP shaft; and a controller. The controller is configured to control the motor-generator to operate in a motor mode to apply torque the LP shaft during a starting of the HP spool assembly, and control the motor-generator to operate in a generator mode for a least a period of time following the starting of the HP spool assembly.

A motoring system for a gas turbine engine having: a reduction gear train having an input and an output; an electric motor operably connected to the input; a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train; and a mechanical shaft fuse operably connecting the output to the clutch, the mechanical shaft fuse in operation shears when torque on the mechanical shaft fuse is greater than or equal to a selected value. The mechanical shaft fuse includes a plurality of through holes.

A motoring system for a gas turbine engine having: a reduction gear train having an input and an output; an electric motor operably connected to the input; a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train; and a mechanical shaft fuse operably connecting the output to the clutch, the mechanical shaft fuse in operation shears when torque on the mechanical shaft fuse is greater than or equal to a selected value. The mechanical shaft fuse includes a plurality of through holes.

A motoring system for a gas turbine engine having: a reduction gear train having an input and output; a motor operably connected to the input; a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train; and a pinned mechanical fuse operably connecting the output to the clutch, the pinned mechanical fuse having at least one shear pin. The pinned mechanical fuse having: an outer sleeve having a first section, second section, inner chamber, outer wall, and at least one through hole connecting the inner chamber to the outer wall within the first section; and an inner sleeve having a first portion, second portion, outer surface, and at least one blind hole located in the outer surface within the second portion. The second portion being located within the inner chamber and operably connected to the outer sleeve through at least one shear pin.

A motoring system for a gas turbine engine having: a reduction gear train having an input and output; a motor operably connected to the input; a clutch operably connected to the output, the clutch in operation engages and disengages the reduction gear train; and a pinned mechanical fuse operably connecting the output to the clutch, the pinned mechanical fuse having at least one shear pin. The pinned mechanical fuse having: an outer sleeve having a first section, second section, inner chamber, outer wall, and at least one through hole connecting the inner chamber to the outer wall within the first section; and an inner sleeve having a first portion, second portion, outer surface, and at least one blind hole located in the outer surface within the second portion. The second portion being located within the inner chamber and operably connected to the outer sleeve through at least one shear pin.

A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.

A gas turbine engine including a first rotor assembly comprising a first drive shaft extended along a longitudinal direction; a housing coupled to the first rotor assembly to provide rotation of the first rotor assembly around an axial centerline; a first accessory assembly, wherein the first accessory assembly sends and/or extracts energy to and from the first rotor assembly; and a first clutch assembly disposed between the first rotor assembly and the first accessory assembly. The first clutch assembly engages and disengages the first rotor assembly to and from the first accessory assembly.

An assembly is provided for a turbine engine. This turbine engine assembly includes a stationary structure, a rotating structure and an electric machine. The rotating structure is rotatably mounted to the stationary structure by a first bearing and a second bearing. The electric machine is between the first bearing and the second bearing. The electric machine includes a rotor and a stator circumscribing the rotor. The rotor is connected to the rotating structure. The stator is connected to the stationary structure.

An assembly is provided for a turbine engine. This turbine engine assembly includes a stationary structure, a rotating structure and an electric machine. The rotating structure is rotatably mounted to the stationary structure by a first bearing and a second bearing. The electric machine is between the first bearing and the second bearing. The electric machine includes a rotor and a stator circumscribing the rotor. The rotor is connected to the rotating structure. The stator is connected to the stationary structure.