Starting and controlling speed of a two spool gas turbine engine

An apparatus for controlling the speed of a two spool gas turbine engine comprising:

• a motor/generator rotationally attached to a gas generator shaft of said gas turbine engine;
• an electrical generator having a drive shaft rotationally attached to a power turbine shaft of said gas turbine engine;
• at least one sensor for measuring at least one condition reflective of a change in an amplitude of an external electric load drawn from said electrical generator;
• and
• a motor/generator controller for powering said motor/generator to adjust the rotational speed of said gas generator shaft.

An apparatus for controlling the speed of a drive shaft of an electrical generator attached to a power turbine shaft of a two spool gas turbine engine comprising:

• a motor/generator rotationally attached to a gas generator shaft of said gas turbine engine;
• at least one sensor for measuring at least one condition reflective of a change in external electric load drawn from said electrical generator;
• a motor/generator controller for powering said motor/generator to adjust the rotational speed of said gas generator shaft;
• and
• an engine control unit for receiving a measurement from said at least one sensor and for instructing said motor/generator controller to drive said motor/generator based on said measurement.

A two spool gas turbine engine comprising:

• a power turbine shaft having an electrical generator rotationally attached thereto;
• a power turbine attached to said power turbine shaft;
• a gas generator shaft driven by a combustor of said gas turbine engine;
• a compressor and a turbine attached to said gas turbine shaft;
• said gas generator shaft providing an air flow to rotate said power turbine and said power turbine shaft, thereby driving said electrical generator;
• a motor/generator rotationally attached to said gas generator shaft;
• at least one sensor for measuring at least one condition reflective of a change in external electric load drawn from said electrical generator;
• and
• a motor/generator controller for powering said motor/generator to adjust the rotational speed of said gas generator shaft to power said electrical generator based on said external electric load.

A method for controlling the speed of a two spool gas turbine engine comprising:

• rotationally attaching a motor/generator to a gas generator shall of said gas turbine engine;
• rotationally attaching a drive shaft of an electrical generator to a power turbine shaft of said gas turbine engine;
• measuring at least one condition reflective of a change in external electric load drawn from said electrical generator;
• and
• adjusting the rotational speed of said gas generator shaft to power said electrical generator based on said external electric load by providing an output from a motor/generator controller to power said motor/generator.