A bowed-rotor prevention system for a turbomachine is disclosed. The system comprises a first turbomachine having a first shaft rotatably supported by a plurality of bearings, a second turbomachine having a second shaft rotatably coupled to the first rotatable shaft, and a pump having a third shaft rotatably coupled to the second shaft. The system further includes a gear box having a fourth shaft rotatably coupled to the third shaft by an clutch configured to operate in a freewheel condition when the first shaft is rotating faster than a first predetermined speed, and further configured to rotatably engage the fourth shaft to the third shaft when the first shaft is rotating slower than a second predetermined speed to thereby drive a rotation of the third shaft, wherein the first predetermined speed is faster than the second predetermined speed.

A gas turbine engine (10) includes a compressor section, a turbine section, and an accessory gearbox (100). A turning unit (200) for the gas turbine engine includes an output assembly (204) configured to be mechanically coupled to the gas turbine engine, and an electric motor (202). The electric motor is operable to rotate, through the output assembly, one or more components of the compressor section or the turbine section at a rotational speed less than about fifty revolutions per minute during a shut-down condition of the gas turbine engine.

An example method includes obtaining a representation of a change in rotational speed of an electric machine; obtaining a representation of an expected change in rotational speed of the electric machine; and determining, based on the obtained representation of the change in rotational speed of the electric machine and the representation of an expected change in rotational speed of the electric machine, whether a disconnect device has failed, wherein, when operating in an engaged state, the disconnect device is configured to couple rotational mechanical energy between the electric machine and a rotating device, and wherein, when operating in a disengaged state, the disconnect device is not configured to couple rotational mechanical energy between the electric machine and the rotating device.

A gas turbine engine includes a fan drive turbine driving a fan rotor through a main gear reduction. A primary lubricant system supplies lubricant to the main gear reduction. An auxiliary oil pump supplies oil to the main gear reduction. An auxiliary pump epicyclic gear train drives the auxiliary pump when the fan rotor is rotating in either direction. The main gear reduction is separate from the auxiliary pump epicyclic gear train.

In one embodiment, a plant control apparatus includes a first stop controller configured to, when stopping a plant, stop a steam turbine to start to drop rotating speed of a second shaft of the steam turbine from rated speed, and start to drop rotating speed of a first shaft of a gas turbine from the rated speed while continuing combustion of a combustor after the stop of the steam turbine. The apparatus further includes a second stop controller configured to shut off fuel of the combustor to stop the gas turbine when the rotating speed of the first shaft drops to first speed. The second stop controller stops the gas turbine such that the rotating speed of the first shaft catches up with the rotating speed of the second shaft at second speed that is equal to or lower than the first speed and a clutch is engaged.

A power extraction system for a gas turbine engine may comprise a low spool transmission and a low spool accessory gearbox. The low spool accessory gearbox may comprise a generator and a dual clutch transmission. The dual clutch transmission may be coupled between the low spool transmission and the generator.

Systems and methods for preventing rotation of an ESP motor when the motor is not powered on, thereby preventing the motor from acting as a generator when fluid flowing through the pump section of the ESP applies a torque to the motor. In one embodiment, an ESP has a motor section, a pump section. The ESP may include a directional coupling that allows unidirectional rotation between the motor shaft and a pump shaft of the pump section, and a directional lock that allows unidirectional rotation between the motor shaft and a housing of the motor section. The directional coupling and directional lock allow the pump shaft to freewheel in the forward direction without causing the motor shaft to rotate, and prevent the pump shaft and motor from rotating in the reverse direction.

A gearbox rigidly coupled to a static structure; a driven component rigidly coupled to another static structure; a clutch assembly floating between and coupled to the gearbox and driven component. The clutch may have aligned output and input shafts, defining an engagement surface, a bearing, and a magnetic friction plate coupled and rotating with the input shaft. The plate may have a friction-engagement face, and a magnetic flux generator. The magnetic flux generator may be rigidly coupled to a static housing and partially surrounded in the radial direction by a structure configured to reduce leakage of a magnetic flux, by defining a plurality of voids, which direct multiple passes of the magnetic flux through the engagement surface of the output shaft. The magnetic flux generator may create the magnetic flux that creates a magnetic force between the engagement face and the magnetic friction plate that causes them to engage.

A gas turbine engine is provided. The gas turbine engine includes a turbomachine comprising a low speed spool; a rotor assembly coupled to the low speed spool; an electric machine mechanically coupled to the low speed spool at a connection point of the low speed spool; and a clutch positioned in the torque path of the low speed spool between the connection point and the rotor assembly

A gas turbine engine is provided. The gas turbine engine defines a radial direction. The engine includes: an airfoil positioned within an airflow and extending between a root end and a tip along the radial direction; and a mount coupled to or formed integrally with the root end of the airfoil for mounting the airfoil to the engine, the mount including an outer surface along the radial direction exposed to the airflow and defining an air-cooling channel extending between an inlet and an outlet, the inlet positioned on the outer surface of the mount.