# US 10,374,486 B2 · Method and assembly of an electric machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,374,486 B2 - Document ID: US10374486B2 - Status: Granted - Kind: B2 - Application number: 15/468,849 - Filed: 2017-03-24 - Published: 2018-09-27 - Granted: 2019-08-06 - Earliest claimed: 2017-03-24 - Assignees: GE Aviation Systems LLC - Applicants: Ge Aviation Systems, LLC - Inventors: Hao Huang; Xiaochuan Jia - Web page: https://patentgrep.com/patent/US10374486B2 ## CPC - H02K 7/20: Structural association with auxiliary dynamo-electric machines, e.g. with electric starter motors or exciters - H02K 1/32: with channels or ducts for flow of cooling medium - H02K 3/24: with channels or ducts for cooling medium between the conductors - H02K 7/1823: {structurally associated with turbines or similar engines} - H02K 9/197: in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A method and assembly of a dry cavity oil cooled electric machine includes a housing, a shaft configured to operably couple with a source of rotational force and rotate about a rotational axis, and an exciter rotor and a permanent magnet generator rotor carried by the shaft, wherein the exciter rotor and the permanent magnet generator rotor rotate relative to the housing, which provides such a construction of dry cavity generators that have high efficiency and high power density. ## Claims ### Claim 1 An electric machine assembly comprising: a housing; a shaft configured to operably couple with a source of rotational force and rotate about a rotational axis and having a shaft cooling passage; an arm carried by and extending radially outward from the shaft and having a first cooling passage different from the shaft cooling passage; and an exciter rotor and a permanent magnet generator rotor carried by the arm; wherein the exciter rotor and the permanent magnet generator rotor are substantially coplanar at a plane orthogonal to the rotational axis. ### Claim 2 (depends on 1) The electric machine assembly of claim 1 wherein the exciter rotor is positioned radially outward from the permanent magnet generator rotor. ### Claim 3 (depends on 1) The electric machine assembly of claim 1, wherein at least one of a main machine stator, a main machine rotor, the rotatable shaft, or a housing is formed by additive manufacturing. ### Claim 4 (depends on 1) The electric machine assembly of claim 1, further comprising an exciter stator carried by the housing and positioned proximate to the exciter rotor and a permanent magnet generator stator carried by the housing and positioned proximate to the permanent magnet generator rotor. ### Claim 5 (depends on 1) The electric machine assembly of claim 1 wherein the exciter rotor and the permanent magnet generator rotor are coplanar at a plane orthogonal to the rotational axis. ### Claim 6 (depends on 1) The electric machine assembly of claim 1 wherein the exciter rotor and the permanent magnet generator rotor at least partially overlap in the axial direction relative to the rotational axis. ### Claim 7 (depends on 1) The electric machine assembly of claim 1 wherein the electric machine generates at least 1 megawatt of electrical power. ### Claim 8 (depends on 1) The electric machine assembly of claim 1 wherein the electric machine includes a power density greater than 7 kiloWatt/kilogram. ### Claim 9 (depends on 1) The electric machine assembly of claim 1 wherein the electric machine is a dry cavity generator. ### Claim 10 (depends on 9) The electric machine assembly of claim 9 further comprising a contained liquid cooling system including a set of cooling passages for liquid coolant to flow through. ### Claim 11 (depends on 10) The electric machine assembly of claim 10 further comprising a main machine rotor carried by the shaft and having at least one rotor pole and at least one second cooling passage located proximate to the at least one rotor pole. ### Claim 12 (depends on 10) The electric machine assembly of claim 10 further comprising a set of stator windings carried by the housing and having a third cooling passage extending through the set of stator windings. ### Claim 13 (depends on 10) The electric machine assembly of claim 10 wherein the liquid coolant is oil. ### Claim 14 A method of operating an electric machine, comprising: rotating a rotatable shaft about a rotational axis, the shaft carrying an arm extending radially outward from the shaft, an exciter rotor, and a permanent magnet generator rotor; and supplying liquid coolant from a rotatable shaft cooling passage to a first contained cooling passage extending through the arm to extract heat from the arm; wherein at least one of the exciter rotor or the permanent magnet generator rotor is mounted to the arm, and wherein the exciter rotor and the permanent magnet generator rotor are substantially coplanar at a plane orthogonal to the rotational axis. ### Claim 15 (depends on 14) The method of claim 14 further comprising supplying liquid coolant to a second contained cooling passage extending through at least one set of stator windings mounted proximate to the rotatable shaft to extract heat from the at least one set of stator windings.