# US 2017/0284302 A1 · Electromagnetic anti-windmilling system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0284302 A1 - Document ID: US20170284302A1 - Status: Published application - Kind: A1 - Application number: 15/089,891 - Filed: 2016-04-04 - Published: 2017-10-05 - Earliest claimed: 2016-04-04 - Assignees: United Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Gary D. Roberge - Web page: https://patentgrep.com/patent/US20170284302A1 ## CPC - F02C 7/26: Starting; Ignition - F01D 15/10: Adaptations for driving, or combinations with, electric generators - F01D 21/006: {Arrangements of brakes (brakes per se F16D)} - F01D 25/28: Supporting or mounting arrangements, e.g. for turbine casing - F02C 3/107: with two or more rotors connected by power transmission - F02C 6/14: Gas-turbine plants having means for storing energy, e.g. for meeting peak loads - F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) - 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) - F02K 3/06: with front fan - F04D 19/002: {Axial flow fans} - F04D 25/026: {with a magnetic coupling} - F04D 25/028: {the driving means being a planetary gear} - F05D 2220/32: in gas turbines - F05D 2220/766: via a direct connection, i.e. a gearless transmission - F05D 2220/768: equipped with permanent magnets - F05D 2260/40311: of the epicyclical, planetary or differential type - F05D 2260/404: through magnetic drive coupling - F05D 2260/903: using electrical or magnetic forces - 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) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A gas turbine engine including a compressor has a first compressor section and a second compressor section, a combustor fluidly connected to the compressor, and a turbine fluidly connected to the combustor. The turbine includes a first turbine section and a second turbine section. A first shaft connects the first compressor section and the first turbine section. A second shaft connects the second compressor section and the second turbine section. A fan is connected to the first shaft via a geared architecture. The first shaft includes at least one magnetic section. An electromagnet is disposed radially outward of the first shaft at an axial location of the at least one magnetic section, relative to an axis defined by the gas turbine engine. ## Claims ### Claim 1 A gas turbine engine comprising: a compressor having a first compressor section and a second compressor section; a combustor fluidly connected to the compressor; a turbine fluidly connected to the combustor, the turbine having a first turbine section and a second turbine section; a first shaft connecting the first compressor section and the first turbine section; a second shaft connecting the second compressor section and the second turbine section; a fan connected to said first shaft via a geared architecture; said first shaft including at least one magnetic section, and an electromagnet disposed radially outward of said first shaft at an axial location of the at least one magnetic section, relative to an axis defined by the gas turbine engine. ### Claim 2 (depends on 1) The gas turbine engine of claim 1, wherein the at least one magnetic section includes a plurality of magnetic sections defined circumferentially around said first shaft at a single axial location. ### Claim 3 (depends on 2) The gas turbine engine of claim 2, wherein the plurality of magnetic sections are distributed about said first shaft in a balanced distribution. ### Claim 4 (depends on 3) The gas turbine engine of claim 3, wherein the balanced distribution is an even distribution. ### Claim 5 (depends on 1) The gas turbine engine of claim 1, wherein said at least one magnetic section extends less than a full circumference of the first shaft. ### Claim 6 (depends on 1) The gas turbine engine of claim 1, wherein the electromagnet is mounted to and structurally supported by an engine static structure. ### Claim 7 (depends on 1) The gas turbine engine of claim 1, further comprising a controller controllably coupled to said electromagnet, the controller storing instructions configured to cause the controller to activate the electromagnet during engine shutdown, and de-activate the electromagnet during engine startup. ### Claim 8 (depends on 7) The gas turbine engine of claim 7, wherein the controller further comprises instructions configured to activate the electromagnet in response rotation speed of said first shaft falling below a predefined threshold. ### Claim 9 (depends on 1) The gas turbine engine of claim 1, wherein the electromagnet is coupled to an on-board power storage device, such that the electromagnet is powered by the on-board power storage device. ### Claim 10 (depends on 1) The gas turbine engine of claim 1, wherein the electromagnet is coupled to a power distribution system, and wherein the power distribution system is configured to receive power from a ground power source. ### Claim 11 (depends on 1) The gas turbine engine of claim 1, wherein the first compressor section is a low pressure compressor section relative to the second compressor section, and wherein the first turbine section is a low pressure turbine section relative to the second turbine section. ### Claim 12 (depends on 1) The gas turbine engine of claim 1, wherein the at least one magnetic section is positioned on said first shaft forward of second compressor section, relative to an expected direction of fluid flow through said gas turbine engine. ### Claim 13 (depends on 12) The gas turbine engine of claim 12, wherein the at least one magnetic section is positioned axially within one of an intermediate case and a fan drive gear section of the gas turbine engine. ### Claim 14 A method for preventing rotation of a shaft in a gas turbine engine comprising: activating an electromagnet within a gas turbine engine; preventing a shaft from rotating using a magnetic field generated by the electromagnet, thereby preventing a fan mechanically coupled to said shaft from rotating. ### Claim 15 (depends on 14) The method of claim 14, wherein activating the electromagnetic within the gas powered turbine is performed in response to a rotation speed of a low shaft falling below a speed threshold. ### Claim 16 (depends on 15) The method of claim 15, wherein the speed threshold is a rotational speed below which the magnetic field is sufficient to stop rotation of the shaft. ### Claim 17 (depends on 15) The method of claim 15, further comprising powering a lubrication system via rotation of a high shaft at least until said electromagnet is activated. ### Claim 18 (depends on 17) The method of claim 17, wherein the lubrication system provides lubrication to at least one journal bearing. ### Claim 19 An anti-windmilling system for a gas turbine engine comprising: an electromagnetic mounted to an engine static structure; and a shaft radially inward of the electromagnet, the shaft including at least one magnetic section at a same axial position of the electromagnet, relative to an axis defined by the shaft. ### Claim 20 (depends on 19) The anti-windmilling system of claim 19, wherein the electromagnet is mounted in one of an engine intermediate case and between a fan drive gear system at a compressor.