Abstract: Fault-tolerant radial flux rotary electric machines are provided. One such machine comprises: a permanent magnet rotor having fourteen poles; and an alternate-wound stator having sixteen slots and four coil pairs, each coil pair forming part of one of four independent electrical phases.

Abstract: There is disclosed a cooling arrangement for a turbine casing (50) of a gas turbine engine (10). The cooling arrangement comprises a first cooling duct (203) that is at least partly within a second cooling duct (204). The first cooling duct is for a first cooling fluid flow and the second cooling duct is for a second cooling fluid flow which flows around the first cooling duct.

Abstract: A method of monitoring the health of a semiconductor power electronic switch such as an insulated gate bipolar transistor (IGBT) is provided. The method having the steps of: measuring one or more parameters selected from the group consisting of: a rate of change of voltage ( dV dt ) across the switch; a rate of change of current ( di dt ) through the switch, a charge present on a gate of the switch (QG), a peak overshoot voltage (VPO) across the switch, and a peak overshoot or reverse recovery current (IRR) through the switch; and estimating the health of the switch based on the measured parameter(s).

Abstract: A mixed propulsion system for a seagoing vessel such as a liquid natural gas carrier including a gas turbine engine is described. The vessel has at least one electric propulsion drive and a plurality of prime movers of different types each coupled directly to drive an electrical generator. The outputs of the several generators are connected to at least two electricity distribution switchboards to supply the power requirements of the vessel, and each electric propulsion drive is cross-coupled to receive power selectively from either switchboard such that in the event of a single failure in a switchboard or prime mover or both power can be maintained to both propulsion drives.