# US 8,932,017 B2 · Wind turbine torque limiting clutch system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,932,017 B2 - Document ID: US8932017B2 - Status: Granted - Kind: B2 - Application number: 12/858,688 - Filed: 2010-08-18 - Published: 2012-02-23 - Granted: 2015-01-13 - Earliest claimed: 2010-08-18 - Assignees: EBO Group, Inc. - Applicants: David C. Heidenreich; Erik L. Olson; Gregg W. Cullings; David A. Peterman - Inventors: David C. Heidenreich; Erik L. Olson; Gregg W. Cullings; David A. Peterman - Web page: https://patentgrep.com/patent/US8932017B2 ## CPC - F03D 9/25: the apparatus being an electrical generator (F03D9/22 takes precedence) - F03D 15/00: Transmission of mechanical power - F03D 15/10: using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members - F03D 17/00: Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30) - F05B 2260/4023: through a friction clutch - F05B 2260/80: Diagnostics - F05B 2270/335: Output power or torque - Y02E 10/72: Wind turbines with rotation axis in wind direction - F03D: WIND MOTORS - F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A wind turbine power generating system includes a wind turbine connected to a speed increasing gearbox having an output shaft. An electrical generator having an input shaft is also provided. An asymmetrical coupling interconnects the input and output shafts. The coupling includes a first torque limiting clutch in series connection with a one-way clutch between the input and output shafts. A second torque limiting clutch is provided in parallel connection with the one-way clutch between the input and output shafts. The first and second torque limiting clutches have different characteristic slip torques. The interconnection of the clutches, and the implementation of the one-way clutch, provides for effective operation of the first and second torque limiting clutches in opposite rotational directions of the input and output shafts. The second torque limiting clutch has a characteristic slip torque that is a fraction of the first torque limiting clutch, the second torque limiting clutch providing protection against reverse impulse loads. ## Claims ### Claim 1 In a wind turbine power generating system comprising a wind turbine connected to a speed increasing gearbox having a high speed output shaft and an electrical generator having an input shaft, the improvement comprising: a coupling system interconnecting said output and input shafts, said coupling system being asymmetrical, having a first characteristic slip torque in a first forward rotational drive direction, and a second characteristic slip torque in a second reverse rotational drive direction. ### Claim 2 (depends on 1) The improvement in a wind turbine power generating system according to claim 1, wherein said first characteristic slip torque is greater than a nominal torque rating of the wind turbine, and said second characteristic slip torque is less than the nominal torque rating of the wind turbine. ### Claim 3 (depends on 2) The improvement in a wind turbine power generating system according to claim 2, wherein said coupling system comprises a first torque limiting clutch having said first characteristic slip torque, and a second torque limiting clutch having said second characteristic slip torque. ### Claim 4 (depends on 3) The improvement in a wind turbine power generating system according to claim 3, further comprising a one-way clutch between said output and input shafts, said one-way clutch being in engagement in said forward rotational direction, and free-wheeling in said reverse rotational direction. ### Claim 5 (depends on 4) The improvement in a wind turbine power generating system according to claim 4, wherein said first torque limiting clutch is in series connection with said one-way clutch between said output and input shafts. ### Claim 6 (depends on 5) The improvement in a wind turbine power generating system according to claim 5, wherein said one-way clutch is in parallel connection with said second torque limiting clutch. ### Claim 7 (depends on 6) The improvement in a wind turbine power generating system according to claim 6, wherein said coupling system comprises concentric hubs, with said one-way clutch and said second torque limiting clutch in parallel interconnection therebetween. ### Claim 8 (depends on 6) The improvement in a wind turbine power generating system according to claim 6, wherein said coupling system comprises a hub about one of said output and input shafts, and wherein said first and second torque limiting clutches and said one-way clutch are interposed between said hub and one of said output and input shafts. ### Claim 9 (depends on 6) The improvement in a wind turbine power generating system according to claim 6, wherein said first and second torque limiting clutches and said one-way clutch each comprise at least one friction drive disk. ### Claim 10 (depends on 6) The improvement in a wind turbine power generating system according to claim 6, wherein at least one of said torque limiting clutches and said one-way clutch are maintained in a sealed enclosure. ### Claim 11 (depends on 10) The improvement in a wind turbine power generating system according to claim 10, wherein said enclosure is filled with an inert gas. ### Claim 12 (depends on 11) The improvement in a wind turbine power generating system according to claim 11, wherein said inert gas is maintained in said enclosure under pressure. ### Claim 13 (depends on 12) The improvement in a wind turbine power generating system according to claim 12, further comprising a pressure indicator providing an indicia of said pressure within said enclosure. ### Claim 14 (depends on 6) The improvement in a wind turbine power generating system according to claim 6, further comprising sensors interconnected among said output and input shafts and said coupling system and connected to a monitor to measure torque within said coupling system. ### Claim 15 (depends on 14) The improvement in a wind turbine power generating system according to claim 14, wherein said sensors enable said monitor to measure slip in said torque limiting clutch. ### Claim 16 (depends on 15) The improvement in a wind turbine power generating system according to claim 15, wherein said sensors comprise variable reluctance metallic ring transducers. ### Claim 17 A wind turbine power generating system, comprising: a wind turbine connected to a speed increasing gearbox having a high speed output shaft; an electrical generator having an input shaft; and an asymmetrical torque limiting coupling interconnecting said input and output shafts, said asymmetrical torque limiting coupling comprising a first torque limiting clutch in series connection with a one-way clutch between said input and output shafts, and a second torque limiting clutch in parallel connection with said one-way clutch between said input and output shafts, said first and second torque limiting clutches having different characteristic slip torques. ### Claim 18 (depends on 17) The wind turbine power generating system according to claim 17, wherein said characteristic slip torque of said second torque limiting clutch is a fraction of said characteristic slip torque of said first torque limiting clutch. ### Claim 19 (depends on 18) The wind turbine power generating system according to claim 18, wherein said first and second torque limiting clutches have effective operation in opposite rotational directions. ### Claim 20 (depends on 19) The wind turbine power generating system according to claim 19, wherein said first and second torque limiting clutches and said one-way clutch are dry and maintained in a sealed enclosure.