GAS TURBINE ENGINE

A gas turbine engine 101 having first and second rotary electric machines 111, 113 mechanically coupled with a spool is provided. The first rotary electric machine 111 is mechanically coupled with the spool and has connected therewith a first power converter 201 to interface the electric machine 111 with a first dc network 203 operating at a first voltage. The second rotary electric machine 113 is mechanically coupled with the spool and has connected therewith a second power converter 204 to interface the electric machine 113 with a second dc network 204 operating at a second voltage greater than said first voltage. The first electric machine 111 and the second electric machine 113 are operable as a motor-generator set for transfer of electrical power to the first dc network 203 from the second dc network 204.