An electric propulsion system for a vertical takeoff-and-landing aircraft having an inverter assembly, a gearbox assembly, an electric motor assembly. The inverter assembly, the gearbox assembly, and the electric motor assembly may be substantially aligned along an axis. The inverter assembly, a gearbox assembly, and electric motor assembly may each abut at least one of the others. The electric engine may use a liquid, such as oil, for cooling and lubricating components of the inverter assembly, gearbox assembly, and electric motor assembly. Further, the electric engine may use volumes of oil for cooling and lubricating components below a threshold volume so that the electric engines do not require a fire protective barrier.

An electrical machine including: a stator core extending along an axial direction and supported by a stator frame. An intermediate plate is provided between the stator core and the stator frame and configured to support the stator core. One of the stator frame and the intermediate plate includes a stopping formation configured to abut the other of the stator frame and the intermediate plate to constrain movement of the stator core relative to the stator frame in at least one direction in the axial direction. The stopping formation is movable relative to the one of the stator frame and the intermediate plate.

An electrical machine including: a stator core extending along an axial direction and supported by a stator frame. An intermediate plate is provided between the stator core and the stator frame and configured to support the stator core. One of the stator frame and the intermediate plate includes a stopping formation configured to abut the other of the stator frame and the intermediate plate to constrain movement of the stator core relative to the stator frame in at least one direction in the axial direction. The stopping formation is movable relative to the one of the stator frame and the intermediate plate.

An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

An electric propulsion system for a vertical take-off and landing (VTOL) aircraft having a heat exchanger to cool fluids used in an electrical engine, the electric propulsion system comprising at least one electrical engine mechanically connected directly or indirectly to a fuselage of the VTOL aircraft and electrically connected to an electrical power source. The electrical engine may comprise an electrical motor having a stator and a rotor; a gearbox assembly comprising a sun gear; at least one planetary gear; a ring gear; and a planetary carrier. The electric engine may include an inverter assembly comprising a thermal plate and an inverter assembly housing; an end bell assembly that is connected to the thermal plate of the inverter assembly; and a heat exchanger comprising an array of cooling fins and tubes.

An electric machine including a direct thermal contact end-winding microchannel heat exchanger is provided. A plurality of insulators are coupled to a stator. A plurality of windings are coupled to the plurality of insulators. A direct thermal contact end-winding microchannel heat exchanger is coupled to a section of the plurality of insulators that extends beyond the stator. The direct thermal contact end-winding microchannel heat exchanger is in direct thermal conduction with a section of the plurality of windings that extends beyond the first end to remove heat from the plurality of windings. According to other illustrative embodiments, a method and modular machine are provided.

An electric machine including a direct thermal contact end-winding microchannel heat exchanger is provided. A plurality of insulators are coupled to a stator. A plurality of windings are coupled to the plurality of insulators. A direct thermal contact end-winding microchannel heat exchanger is coupled to a section of the plurality of insulators that extends beyond the stator. The direct thermal contact end-winding microchannel heat exchanger is in direct thermal conduction with a section of the plurality of windings that extends beyond the first end to remove heat from the plurality of windings. According to other illustrative embodiments, a method and modular machine are provided.

An electrical machine is described which comprises: a rotor; a plurality of stator units each extending only partway about a circumference of the rotor; wherein each stator unit is movably mounted to the rotor by a plurality of bearings such that the stator unit can move relative to the rotor in a radial and/or axial direction and wherein each stator unit is fixed in position in a circumferential direction; wherein the electrical machine comprises a magnetic system arranged such that rotation of the rotor generates an electric current in each stator unit and/or an electric current in each stator unit causes rotation of the rotor. A system comprising an electrical machine and a remote assembly and maintenance apparatus is also described, along with methods of assembling and disassembling an electrical machine.

An electrical machine is described which comprises: a rotor; a plurality of stator units each extending only partway about a circumference of the rotor; wherein each stator unit is movably mounted to the rotor by a plurality of bearings such that the stator unit can move relative to the rotor in a radial and/or axial direction and wherein each stator unit is fixed in position in a circumferential direction; wherein the electrical machine comprises a magnetic system arranged such that rotation of the rotor generates an electric current in each stator unit and/or an electric current in each stator unit causes rotation of the rotor. A system comprising an electrical machine and a remote assembly and maintenance apparatus is also described, along with methods of assembling and disassembling an electrical machine.

An electric motor has a housing with a main part and a side cover; a stator; a rotor having a rotor shaft; and a rolling bearing assembly located on a first side of the stator. The rotor shaft is mounted with the side cover via the first rolling bearing assembly, which transmit axial loads exerted on the rotor shaft to the side cover. The side cover is fixedly secured to the main part, located on the first side of the stator. The side cover abuts against the first rolling bearing assembly, so that said axial loads are transmitted to the main part by the side cover. When the side cover is not secured to the main part, the housing is open, allowing insertion of the rotor into the stator via the first side of the stator.