Electric machine

A gas turbine engine defining an engine centerline and comprising:

• a turbomachine comprising a turbine and a rotating assembly configured to rotate about the centerline, the rotating assembly comprises a shaft rotatable with the turbine;
• and
• an electric machine defining an electric machine centerline, the electric machine comprising
• a stator assembly defining a first surface;
• a rotor assembly rotatable with the rotating assembly of the turbomachine relative to the stator assembly about the electric machine centerline and defining a second surface opposing the first surface, the rotor assembly also comprises a connection assembly and a rotor, and wherein the connection assembly extends between the shaft and the rotor;
• an air gap formed between the first surface and the second surface that corresponds to a minimum distance between the stator assembly and the rotor assembly;
• and
• an actuator coupled to the connection assembly for moving the connection assembly along the electric machine centerline relative to the shaft so as to move the rotor assembly between a first position and a second position, the connection assembly being connected to the shaft through a splined connection, and
• wherein the minimum distance is less in the first position than in the second position.

A method of operating an electric machine,

• the electric machine comprising:
• a stator assembly defining a first surface,
• a rotor assembly defining a second surface opposing the first surface, the rotor assembly comprises a connection assembly and a rotor, the connection assembly extends between a shaft of a turbomachine and the rotor, the connection assembly being connected to the shaft through a splined connection, the shaft being rotatable with a turbine of the turbomachine, and
• an air gap formed between the first surface and the second surface and corresponding to a minimum distance between the stator assembly and the rotor assembly,
• the electric machine defining a centerline,
• the method comprising:
• operating the electric machine to convert electrical power to rotational power, to convert rotational power to electrical power, or both while the rotor assembly is in a first position relative to the stator assembly;
• receiving information indicative of a fault condition within the electric machine;
• and
• moving, with an actuator coupled with the connection assembly, the connection assembly so as to move the rotor assembly relative to the stator assembly along the centerline of the electric machine from the first position to a second position in response to receiving information indicative of the fault condition within the electric machine,
• wherein the minimum distance is less in the first position than in the second position.