# US 2015/0145554 A1 · Method for inspecting wye ring > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0145554 A1 - Document ID: US20150145554A1 - Status: Published application - Kind: A1 - Application number: 14/089,915 - Filed: 2013-11-26 - Published: 2015-05-28 - Earliest claimed: 2013-11-26 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Thomas Earnest Moldenhauer; Thomas James Batzinger; Francis Alexander Reed; Michael Charles Freda - Web page: https://patentgrep.com/patent/US20150145554A1 ## CPC - G01R 31/346: {Testing of armature or field windings} - F03D 17/00: Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30) - G01R 31/343: {in operation} - Y02E 10/72: Wind turbines with rotation axis in wind direction - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - F03D: WIND MOTORS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A method for inspecting a wye ring in a generator includes the steps of dismantling the generator to gain access to the wye ring and at least a portion of a rotor, applying a test signal to the rotor and measuring an inductive voltage at two or more locations near the wye ring. A comparing step compares results from the measuring step to determine if a fault exists in the wye ring. A predetermined difference in inductive voltage measurements indicates presence of the fault. ## Claims ### Claim 1 A method for inspecting a wye ring in a generator, the method comprising the steps of: dismantling the generator to gain access to the wye ring and at least a portion of a rotor; applying a test signal to the rotor; measuring an inductive voltage at two or more locations near the wye ring; comparing results from the measuring step to determine if a fault exists in the wye ring, a predetermined difference in inductive voltage measurements indicating presence of the fault. ### Claim 2 (depends on 1) The method of claim 1, the dismantling step further comprising: moving a heat exchanger to gain access to the wye ring. ### Claim 3 (depends on 1) The method of claim 1, the dismantling step further comprising: removing a slip ring housing and a bearing shield from the generator. ### Claim 4 (depends on 1) The method of claim 1, the applying step further comprising: applying the test signal to two connection lugs of the generator, a first connection lug being grounded and a second connection lug receiving the test signal, wherein the connection lugs are electrically connected to the wye ring, and wherein the first connection is electrically connected to a first phase of the rotor and the second connection is electrically connected to a second phase of the rotor. ### Claim 5 (depends on 4) The method of claim 4, the test signal comprising an alternating current (AC) at about 1 MHz. ### Claim 6 (depends on 5) The method of claim 5, the test signal comprising a voltage of about 10 volts. ### Claim 7 (depends on 1) The method of claim 1, the measuring step further comprising: measuring the inductive voltage with a radio frequency (RF) pickup coil at multiple locations. ### Claim 8 (depends on 7) The method of claim 7, the measuring step further comprising: measuring the inductive voltage on both sides of a second connection lug along the wye ring; wherein a first connection lug is connected to ground and the second connection lug receives the test signal, and wherein the connection lugs are electrically connected to the wye ring. ### Claim 9 (depends on 7) The method of claim 7, the measuring step further comprising: measuring the inductive voltage at points spaced by about 120 degrees along the wye ring; and wherein the points span the wye ring and are between each of a first connection lug, a second connection lug and a third connection lug. ### Claim 10 (depends on 1) The method of claim 1, the comparing step further comprising: evaluating the difference between inductive voltage measurements at different locations along the wye ring, and wherein a difference of about 50% or more indicating presence of the fault. ### Claim 11 (depends on 1) The method of claim 1, wherein the method is performed on the generator in-situ. ### Claim 12 (depends on 1) The method of claim 1, the applying step further comprising: applying the test signal to a first connection lug and a second connection lug, the first connection lug connected to the wye ring and a first phase of the rotor, the second connection lug connected to the wye ring and a second phase of the rotor; applying the test signal to the second connection lug and a third connection lug, the third connection lug connected to the wye ring and a third phase of the rotor; and applying the test signal to the first connection lug and the third connection lug. ### Claim 13 A method for inspecting a wye ring in a generator, the method comprising the steps of: applying a test signal to the rotor; measuring an inductive voltage at two or more locations near the wye ring; comparing results from the measuring step to determine if a fault exists in the wye ring, a predetermined difference in inductive voltage measurements indicating presence of the fault; and wherein the method is performed on the generator in-situ. ### Claim 14 (depends on 13) The method of claim 13, the applying step further comprising: applying the test signal to two connection lugs of the generator, a first connection lug being grounded and a second connection lug receiving the test signal, wherein the two connection lugs are electrically connected to the wye ring. ### Claim 15 (depends on 14) The method of claim 14, the test signal comprising an alternating current (AC) at about 1 MHz and having a voltage of about 10 volts. ### Claim 16 (depends on 14) The method of claim 14, the measuring step further comprising: measuring the inductive voltage with a radio frequency (RF) pickup coil at multiple locations. ### Claim 17 (depends on 13) The method of claim 13, the measuring step further comprising: measuring the inductive voltage on both sides of a second connection lug along the wye ring; wherein a first connection lug is connected to ground and the second connection lug receives the test signal, and wherein the connection lugs are electrically connected to the wye ring. ### Claim 18 (depends on 13) The method of claim 13, the measuring step further comprising: measuring the inductive voltage at points spaced by about 120 degrees along the wye ring; and wherein the points span the wye ring and are between each of a first connection lug, a second connection lug and a third connection lug. ### Claim 19 (depends on 13) The method of claim 13, the comparing step further comprising: evaluating the difference between inductive voltage measurements at different locations along the wye ring, and wherein a difference of about 50% or more indicating presence of the fault. ### Claim 20 (depends on 13) The method of claim 13, the applying step further comprising: applying the test signal to a first connection lug and a second connection lug, the first connection lug connected to the wye ring and a first phase of the rotor, the second connection lug connected to the wye ring and a second phase of the rotor; applying the test signal to the second connection lug and a third connection lug, the third connection lug connected to the wye ring and a third phase of the rotor; and applying the test signal to the first connection lug and the third connection lug.