Abstract: The disclosure relates to winding arrangements for electrical machine stators. Example embodiments include a coil for a tooth element of an electrical machine stator, the coil formed from a plurality of hairpin wires having pairs of legs passing through first and second slots on opposing radial faces of the tooth element, the coil having n full turns passing around the tooth element, the first and second slots each having 2n+2 slot positions having a depth d? for accommodating a single hairpin wire, the slots each having a first slot position at a first common end and a 2n+2th slot position at a second opposing end, the coil having first and second terminal connections connected to hairpin wires extending through the first and second slots at respective first and second slot positions.

Abstract: Turbomachinery comprising first and second sets of rotors configured to operate on a working fluid. The machinery further comprises first and second sets of electric machines coupled to the respective first and second rotors, and a coupling arrangement arranged to couple adjacent rotors of the first and second rotor sets to provide for fixed ratio, contra-rotation of the first and second rotor sets.

Abstract: A method of controlling two or more sources of electrical power to supply electrical power to a shared bus. Each source of electrical power has a rated power Pr, a maximum overload power Pm, and is operable along a multi-voltage droop slope, the multi-voltage droop slope including a share region and a catch region, the share region being defined by an upper voltage limit, Vhigh and a base voltage Vbase, and the catch region being defined by the base voltage Vbase and a lower voltage limit Vlow.

Abstract: The disclosure relates to winding arrangements for electrical machine stators. Example embodiments include a coil for a tooth element of an electrical machine stator, the coil formed from a plurality of hairpin wires having pairs of legs passing through first and second slots on opposing radial faces of the tooth element, the coil having n full turns passing around the tooth element, the first and second slots each having 2n+2 slot positions having a depth d? for accommodating a single hairpin wire, the slots each having a first slot position at a first common end and a 2n+2th slot position at a second opposing end, the coil having first and second terminal connections connected to hairpin wires extending through the first and second slots at respective first and second slot positions.

Abstract: Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

Abstract: Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

Abstract: A method of controlling two or more sources of electrical power to supply electrical power to a shared bus. Each source of electrical power has a rated power Pr, a maximum overload power Pm, and is operable along a multi-voltage droop slope, the multi-voltage droop slope including a share region and a catch region, the share region being defined by an upper voltage limit, Vhigh and a base voltage Vbase, and the catch region being defined by the base voltage Vbase and a lower voltage limit Vlow.

Abstract: Turbomachinery comprising first and second sets of rotors configured to operate on a working fluid. The machinery further comprises first and second sets of electric machines coupled to the respective first and second rotors, and a coupling arrangement arranged to couple adjacent rotors of the first and second rotor sets to provide for fixed ratio, contra-rotation of the first and second rotor sets.

Abstract: A permanent magnet electrical machine (30) comprising a first shaft having a rotational axis (34). A second shaft spaced from the first shaft and rotating about the rotational axis. The second shaft comprises magnetic material. A first magnet mounted to the first shaft or aligned with the first shaft to selectively magnetise at least a portion of the first shaft. A second magnet aligned with the second shaft to selectively magnetise at least a portion of the second shaft and thereby to couple the second shaft to the first shaft.