GAS TURBINE ENGINE INCORPORATING A VARIABLE GEAR RATIO ELECTRICAL MACHINE

An electrical machine (30) comprising a moveable permanent magnet component (32) configured to generate a first magnetic field. A stator (44) comprising windings configured to excite a second magnetic field. A moveable inter-pole component (52) located between the permanent magnet component and the stator, the inter-pole component comprising an array of magnetic inter-pole pieces (54). The speed of movement of the inter-pole component is controlled to set a magnetic gear ratio between the first and second magnetic fields. Also a gas turbine engine, propulsor or thruster incorporating the electrical machine.