Patents by Inventor Vaiyapuri VISWANATHAN
Vaiyapuri VISWANATHAN has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10892664Abstract: An electrical machine has a variable reluctance rotor, and a stator formed as an annular array of stator segments. The reluctance of the rotor-to-stator magnetic flux path varies with rotor position whereby the stator segments are magnetically energizable to rotate the rotor. The stator segments are arranged in the array such that, when energized to rotate the rotor, they produce an unbalanced force on the rotor. The machine further has a compensator including one or more balancing segments which are configured to be magnetically energizable to produce a balancing force on the rotor which balances the unbalanced force. The reluctance of the rotor-to-compensator magnetic flux path is substantially invariant with rotor position.Type: GrantFiled: September 7, 2018Date of Patent: January 12, 2021Assignee: ROLLS-ROYCE plcInventors: Ellis F H Chong, Shanmukha Ramakrishna, Vaiyapuri Viswanathan, Shuai Wang
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Patent number: 10725107Abstract: A method of classifying a stator winding fault in a brushless synchronous generator includes measuring an electrical parameter of the stator winding and classifying the fault by calculating positive or negative sequence harmonics of the parameter and comparing one or more harmonic component to a threshold.Type: GrantFiled: September 12, 2017Date of Patent: July 28, 2020Assignee: ROLLS-ROYCE plcInventors: Sivakumar Nadarajan, Amit Gupta, Vaiyapuri Viswanathan, Chandana Gajanayake
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Patent number: 10408879Abstract: A method for diagnosing a fault condition in an electric machine includes measuring at least one physical parameter generated during operation of the electric machine; analyzing the or each measured parameter in a frequency domain; and determining whether the electric machine has a stator or rotor winding fault based on a comparison of an amplitude of the or each analyzed parameter at a first predetermined frequency and a first threshold amplitude for the first frequency. The at least one physical parameter includes a sound generated by the electric machine.Type: GrantFiled: September 15, 2017Date of Patent: September 10, 2019Assignee: ROLLS-ROYCE plcInventors: Sivakumar Nadarajan, Amit K. Gupta, Vaiyapuri Viswanathan
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Publication number: 20190081532Abstract: An electrical machine has a variable reluctance rotor, and a stator formed as an annular array of stator segments. The reluctance of the rotor-to-stator magnetic flux path varies with rotor position whereby the stator segments are magnetically energizable to rotate the rotor. The stator segments are arranged in the array such that, when energized to rotate the rotor, they produce an unbalanced force on the rotor. The machine further has a compensator including one or more balancing segments which are configured to be magnetically energizable to produce a balancing force on the rotor which balances the unbalanced force. The reluctance of the rotor-to-compensator magnetic flux path is substantially invariant with rotor position.Type: ApplicationFiled: September 7, 2018Publication date: March 14, 2019Applicant: ROLLS-ROYCE plcInventors: Ellis FH CHONG, Shanmukha RAMAKRISHNA, Vaiyapuri VISWANATHAN, Shuai WANG
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Patent number: 10082531Abstract: A rectifier diode failure detection apparatus for an electrical machine (10), the electrical machine (10) comprising an exciter armature winding (28a-c), a rotor main field winding (24) and first and second rectifiers (34a, 34b) arranged in parallel, each rectifier (34a, 34b) comprising at least first and second diodes (38a, 38b), each rectifier being configured to independently supply the rotor main field winding (24) with DC electrical current, the failure detection apparatus comprising: a controller (40) comprising at least two current sensors (42a, 42b), each current sensor (42a, 42b) being configured to measure output current (If1, If2) of a respective one of the rectifiers (34a, 34b), and the controller (40) being configured to determine a harmonic of the measured rectifier output currents; the controller (40) being further configured to determine a ratio of the magnitude of the first rectifier (34a) output current harmonic to the magnitude of the second rectifier (34b) output current harmonic, whereinType: GrantFiled: November 9, 2016Date of Patent: September 25, 2018Assignee: ROLLS-ROYCE plcInventors: Vaiyapuri Viswanathan, Sivakumar Nadarajan, Amit K. Gupta
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Publication number: 20180100895Abstract: There is disclosed a method for diagnosing a fault condition in an electric machine 4. The method comprises measuring S2 at least one physical parameter generated during operation of the electric machine 4; analysing S4 the or each measured parameter in a frequency domain; and determining S12 whether the electric machine 4 has a stator or rotor winding fault based on a comparison of an amplitude of the or each analysed parameter at a first predetermined frequency and a first threshold amplitude for the first frequency. The at least one physical parameter comprises a sound generated by the electric machine 4.Type: ApplicationFiled: September 15, 2017Publication date: April 12, 2018Applicant: ROLLS-ROYCE plcInventors: Sivakumar NADARAJAN, Amit K. GUPTA, Vaiyapuri VISWANATHAN
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Publication number: 20180095134Abstract: A method of classifying a stator winding fault in a brushless synchronous generator includes measuring an electrical parameter of the stator winding and classifying the fault by calculating positive or negative sequence harmonics of the parameter and comparing one or more harmonic component to a threshold.Type: ApplicationFiled: September 12, 2017Publication date: April 5, 2018Applicant: ROLLS-ROYCE plcInventors: Sivakumar NADARAJAN, Amit GUPTA, Vaiyapuri VISWANATHAN, Chandana GAJANAYAKE
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Patent number: 9910083Abstract: A method of detecting a diode fault in an AC signal rectifier circuit, the AC signal rectifier circuit including a plurality of diodes, and being arranged to supply a rectified output voltage to a load, wherein the method includes the steps of deriving an operating value indicative of the ratio of the voltage magnitudes of a first harmonic frequency and another harmonic frequency of the rectified output voltage across the load; and determining whether a fault has occurred in one or more diodes on the basis of the derived operating value. The first harmonic frequency is preferably the fundamental harmonic frequency, and/or the another harmonic frequency is preferably the 6th harmonic frequency.Type: GrantFiled: December 17, 2014Date of Patent: March 6, 2018Assignee: ROLLS-ROYCE PLCInventors: Vaiyapuri Viswanathan, Amit Kumar Gupta, Chandana Jayampathi Gajanayake, Sivakumar Nadarajan
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Publication number: 20170160330Abstract: A rectifier diode failure detection apparatus for an electrical machine (10), the electrical machine (10) comprising an exciter armature winding (28a-c), a rotor main field winding (24) and first and second rectifiers (34a, 34b) arranged in parallel, each rectifier (34a, 34b) comprising at least first and second diodes (38a, 38b), each rectifier being configured to independently supply the rotor main field winding (24) with DC electrical current, the failure detection apparatus comprising: a controller (40) comprising at least two current sensors (42a, 42b), each current sensor (42a, 42b) being configured to measure output current (If1, If2) of a respective one of the rectifiers (34a, 34b), and the controller (40) being configured to determine a harmonic of the measured rectifier output currents; the controller (40) being further configured to determine a ratio of the magnitude of the first rectifier (34a) output current harmonic to the magnitude of the second rectifier (34b) output current harmonic, whereinType: ApplicationFiled: November 9, 2016Publication date: June 8, 2017Applicant: ROLLS-ROYCE plcInventors: Vaiyapuri VISWANATHAN, Sivakumar NADARAJAN, Amit K. GUPTA
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Patent number: 9459320Abstract: A method for detecting a fault in an exciter circuit, suitable for use in a brushless generator, the exciter circuit including (a) an exciter armature winding, having a plurality of armatures, arranged to generate a multiphase AC signal, each armature of the plurality of armatures providing a respective sub-signal component of the multiphase AC signal, and (b) a rectifier circuit for receiving the sub-signals via the respective armatures, the rectifier circuit comprising a plurality of components arranged to rectify the sub-signals to provide a rectified output signal, wherein the method includes the steps of: acquiring a respective operational sub-value for a first characteristic of each of at least two of the respective sub-signals; deriving an operational value indicative of a relationship between the acquired respective operational sub-values; determining whether a fault has occurred in the exciter circuit on the basis of the derived operational value.Type: GrantFiled: December 17, 2014Date of Patent: October 4, 2016Assignee: ROLLS-ROYCE plcInventors: Vaiyapuri Viswanathan, Chandana Gajanayake, Amit Gupta, Sivakumar Nadarajan
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Publication number: 20150198668Abstract: A method for detecting a fault in an exciter circuit, suitable for use in a brushless generator, the exciter circuit including (a) an exciter armature winding, having a plurality of armatures, arranged to generate a multiphase AC signal, each armature of the plurality of armatures providing a respective sub-signal component of the multiphase AC signal, and (b) a rectifier circuit for receiving the sub-signals via the respective armatures, the rectifier circuit comprising a plurality of components arranged to rectify the sub-signals to provide a rectified output signal, wherein the method includes the steps of: acquiring a respective operational sub-value for a first characteristic of each of at least two of the respective sub-signals; deriving an operational value indicative of a relationship between the acquired respective operational sub-values; determining whether a fault has occurred in the exciter circuit on the basis of the derived operational value.Type: ApplicationFiled: December 17, 2014Publication date: July 16, 2015Inventors: Vaiyapuri VISWANATHAN, Chandana GAJANAYAKE, Amit GUPTA, Sivakumar NADARAJAN
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Publication number: 20150198655Abstract: A method of detecting a diode fault in an AC signal rectifier circuit, the AC signal rectifier circuit including a plurality of diodes, and being arranged to supply a rectified output voltage to a load, wherein the method includes the steps of deriving an operating value indicative of the ratio of the voltage magnitudes of a first harmonic frequency and another harmonic frequency of the rectified output voltage across the load; and determining whether a fault has occurred in one or more diodes on the basis of the derived operating value. The first harmonic frequency is preferably the fundamental harmonic frequency, and/or the another harmonic frequency is preferably the 6th harmonic frequency.Type: ApplicationFiled: December 17, 2014Publication date: July 16, 2015Inventors: Vaiyapuri VISWANATHAN, Amit Kumar GUPTA, Chandana Jayampathi GAJANAYAKE, Sivakumar NADARAJAN