# US 10,873,243 B2 · Electrical machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,243 B2 - Document ID: US10873243B2 - Status: Granted - Kind: B2 - Application number: 15/795,492 - Filed: 2017-10-27 - Published: 2018-05-10 - Granted: 2020-12-22 - Earliest claimed: 2016-11-04 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Geraint W. Jewell; Adam J. McLoughlin; Ellis F H Chong - Web page: https://patentgrep.com/patent/US10873243B2 ## CPC - H02K 7/1085: {Magnetically influenced friction clutches} - F16D 11/14: with clutching members movable only axially (F16D11/02, F16D11/08 take precedence) - F16D 27/01: with permanent magnets - F16D 27/108: with axially movable clutching members - F16D 27/118: with interengaging jaws or gear teeth - H02K 1/272: the magnetisation axis of the magnets being perpendicular to the rotor axis - H02K 7/125: {magnetically influenced} - H02K 7/1823: {structurally associated with turbines or similar engines} - F02C 7/36: Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) - F05D 2260/403: through the shape of the drive components - Y02E 10/72: Wind turbines with rotation axis in wind direction - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract An electrical machine comprising a two-part rotor formed of a first rotor part and a second rotor part. The first rotor part includes a conical section and is mounted to a shaft of the machine. The second rotor part has a bore including a complementary conical section. The second rotor part is configured to displace axially between a first state, in which it is engaged with the first rotor part to form the rotor of the electrical machine, and a second state, in which it is axially disengaged from the first rotor part. Also a clutch having an engaged state and a disengaged state. When the clutch is in one of its states the second rotor part is in its first state and switching the clutch to the other of its states axially displaces the second rotor part to its second state. ## Claims ### Claim 1 An electrical machine comprising: a two-part rotor having a rotational axis and formed of: a first rotor part which includes a conical section and which is mounted to a shaft of the machine; a second rotor part positioned radially outside the first rotor part and which has a bore including a complementary conical section, the second rotor part configured to displace axially between a first state, in which the second rotor part is engaged with the first rotor part to form the rotor of the electrical machine, and a second state, in which the second rotor part is axially disengaged from the first rotor part, the second rotor part including an annular array of permanent magnets on an outer periphery; a stator including electrical coils and being positioned radially outside the two-part rotor; and a clutch having an engaged state and a disengaged state; wherein when the clutch is in one of the engaged and disengaged states the second rotor part is in the first state, wherein a switch of the clutch to the other of the engaged and disengaged states axially displaces the second rotor part to the second state, and wherein the clutch comprises an electromagnetic actuator. ### Claim 2 (depends on 1) An electrical machine as claimed in claim 1 wherein when the clutch is in the engaged state the second rotor part is in the first state and a switch of the clutch to the disengaged state axially displaces the second rotor part to the second state. ### Claim 3 (depends on 1) An electrical machine as claimed in claim 1 wherein when the clutch is in the disengaged state the second rotor part is in the first state and a switch of the clutch to the engaged state axially displaces the second rotor part to the second state. ### Claim 4 (depends on 1) An electrical machine as claimed in claim 1 wherein the electromagnetic actuator includes a DC coil. ### Claim 5 (depends on 4) An electrical machine as claimed in claim 4 wherein the electromagnetic actuator further comprises one or more permanent magnets. ### Claim 6 (depends on 1) An electrical machine as claimed in claim 1 wherein the clutch comprises a non-rotating member and a rotating member, the rotating member coupled to the second rotor part. ### Claim 7 (depends on 6) An electrical machine as claimed in claim 6 wherein the non-rotating member comprises a coil and the rotating member comprises a ferromagnetic plate. ### Claim 8 (depends on 1) An electrical machine as claimed in claim 1 wherein the electrical machine comprises a permanent magnet electrical machine. ### Claim 9 (depends on 1) An electrical machine as claimed in claim 1 wherein the conical section and the complementary conical section include positive engagement features. ### Claim 10 (depends on 9) An electrical machine as claimed in claim 9 wherein the positive engagement features comprise splines. ### Claim 11 (depends on 1) An electrical machine as claimed in claim 1 wherein the first and second rotor parts each comprise more than one complementary conical section. ### Claim 12 (depends on 1) An electrical machine as claimed in claim 1 further comprising a bias member to bias the second rotor part into the second state. ### Claim 13 (depends on 12) An electrical machine as claimed in claim 12 wherein the bias member is selected from the group consisting of a compliant member, a spring, and a Belleville washer. ### Claim 14 (depends on 1) An electrical machine as claimed in claim 1 further comprising a bias member to bias the second rotor part into the first state. ### Claim 15 (depends on 1) An electrical machine as claimed in claim 1, wherein the electrical machine is a generator and the electromagnetic actuator is configured to position the second rotor part in the second state, in which the second rotor part is axially disengaged from the first rotor part.