Gas turbine engine fuel system

A fuel system for a gas turbine engine, the gas turbine engine comprising a combustor having a fuel injector, the gas turbine engine comprising a main alternating current electrical generator driven by an engine shaft such that an electrical output frequency of the electrical generator varies in dependence on engine rotational speed, the fuel system comprising:

• a variable flow fuel pump configured to provide a fuel flow to the fuel injector;
• a frequency and/or voltage controller configured to provide electrical power having at least one of a predetermined output frequency and a predetermined voltage;
• and
• a variable speed electric motor configured to drive the fuel pump;
• the electric motor comprising an induction motor having a stator and at least a first rotor, the stator having first and second sets of stator windings, each set of stator windings being configured to impart a torque on the first rotor to drive the fuel pump in use, the first set of stator windings being supplied only with electrical power from an AC bus powered by the main generator, the electrical power from the AC bus supplied to the first set of stator windings having a same electrical output frequency and voltage as the electrical output frequency and voltage output by the main generator, and the second set of stator windings being supplied only with electrical power output from the frequency and/or voltage controller.