ABB Schweiz AGDownload PDFPatent Trials and Appeals BoardDec 23, 20212021004937 (P.T.A.B. Dec. 23, 2021) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/762,459 03/22/2018 Pedro RODRIGUEZ 04190-P0299A 7778 137670 7590 12/23/2021 ABB - Whitmyer IP Group LLC 600 Summer Street Stamford, CT 06901 EXAMINER LAUGHLIN, CHARLES S ART UNIT PAPER NUMBER 2846 NOTIFICATION DATE DELIVERY MODE 12/23/2021 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): USPTO@dockettrak.com uspto@whipgroup.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte PEDRO RODRIGUEZ, SUBRAT SAHOO, CAJETAN PINTO, and KLAUS VÄNSKÄ ___________ Appeal 2021–004937 Application 15/762,459 Technology Center 2800 ____________ Before ALLEN R. MacDONALD, CARL W. WHITEHEAD JR. and DAVID J. CUTTITA II, Administrative Patent Judges. WHITEHEAD JR., Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE1 1 Rather than reiterate Appellant’s arguments and the Examiner’s determinations, we refer to the Appeal Brief (filed February 3, 2021), the Reply Brief (filed August 13, 2021), the Final Action (mailed October 19, 2020) and the Answer (mailed July 2, 2021), for the respective details. An oral hearing was held on December 13, 2021. A transcript of that hearing will be added to the record once available. Appeal 2021-004937 Application 15/762,459 2 Appellant2 is appealing the final rejection of claims 1–20 under 35 U.S.C. § 134(a). See Appeal Brief 2. Claims 1 and 13 are independent. We have jurisdiction under 35 U.S.C. § 6(b). We reverse. Introduction According to Appellant: Shaft voltages are a well-known problem in electrical machines. Changing magnetic fields around the shaft induce to the shaft currents that may result into very high voltage differences between the opposite ends of the shaft and the ground. Currents and corresponding voltages may also occur in stator core laminations of electrical machines. Specification ¶ 2. The present invention relates to an avoidance of undesired frequency components of voltages in electrical machines. It particularly relates to protection of electrical machines and load against harmful shaft voltages that can cause bearing currents and consequently damage bearings. Specification ¶ 1. The claimed invention is based on the realization that in order to get rid of harmful shaft voltages in the form of sharp voltage peaks at high frequencies, it is first necessary to determine at which undesired frequency or frequencies these voltage peaks occur. Only thereafter can a low impedance grounding be provided that works satisfactorily at the undesired frequency or frequencies. Specification ¶ 14. 2 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42(a) (“The word ‘applicant’ when used in this title refers to the inventor or all of the joint inventors, or to the person applying for a patent as provided in §§ 1.43, 1.45, or 1.46.”). Appellant identifies ABB Schweiz AG, of CH- 5400 Baden, Switzerland as the real party in interest. Appeal Brief 2. Appeal 2021-004937 Application 15/762,459 3 Appellant states, “By way of the claimed invention, active grounding is provided, and a potentially harmful effect of the at least one frequency component in the electrical machine can be avoided.” Appeal Brief 5 (citing Specification ¶ 15). Representative Claim3 (disputed limitations emphasized) 1. A method for preventing at least one frequency component of a voltage from occurring in an electrical machine, the method comprising the steps of: -obtaining, either by measuring a voltage signal or a current signal from the electrical machine in time domain and transforming the measured signal into frequency domain, by simulating the electrical machine, or by deducing from operation settings of an inverter, a first frequency component present in the electrical machine in absence of a grounding, the first frequency component representing a first undesired frequency higher than a limit frequency of 500 Hz; and -providing the electrical machine with a first grounding at a grounding location, the first grounding comprising a resonant circuit resonating at the first undesired frequency, wherein the resonant circuit provides a low grounding impedance at the first undesired frequency. 3 Appellant does not argue the independent claims individually. See Appeal Brief 4 (“The claimed invention, as recited in independent claims 1 and 13, would not have been anticipated by Hobelsberger.”). Accordingly, we select independent claim 1 as representative. See 37 C.F.R. § 41.37(c)(1)(iv) (“When multiple claims subject to the same ground of rejection are argued as a group or subgroup by appellant, the Board may select a single claim from the group or subgroup and may decide the appeal as to the ground of rejection with respect to the group or subgroup on the basis of the selected claim alone.”). Appeal 2021-004937 Application 15/762,459 4 References Name4 Reference Date Thanawala US 3,881,137 April 29, 1975 Raith US 2002/0117913 A1 August 29, 2002 Hobelsberger US 2009/0179663 A1 July 16, 2009 Dillig US 2013/0170077 A1 July 4, 2013 Rejections on Appeal Claims 1, 2, 4–7, 9, 10 and 13–20 stand rejected under 35 U.S.C. § 102(a)(1)/(a)(2) as being anticipated by Hobelsberger. Final Action 2–7. Claim 8 stands rejected under 35 U.S.C. § 103 as being unpatentable over Hobelsberger and Thanawala. Final Action 7–8. Claims 11 and 12 stand rejected under 35 U.S.C. § 103 as being unpatentable over Hobelsberger and Dillig. Final Action 8–9. Claim 3 stands rejected under 35 U.S.C. § 103 as being unpatentable over Hobelsberger and Raith. Final Action 9. ANALYSIS 35 U.S.C. § 102 Rejection Appellant contends “the rejection of independent claims 1 and 13 under 35 U.S.C. § 102” should be reversed because “Hobelsberger fails to disclose the first grounding comprising a resonant circuit resonating at the first undesired frequency, wherein the resonant circuit provides a low 4 All reference citations are to the first named inventor only. Appeal 2021-004937 Application 15/762,459 5 grounding impedance at the first undesired frequency.” Appeal Brief 5. The Examiner finds Hobelsberger teaches: providing the electrical machine (1) with a first grounding at a grounding location (11), the first grounding comprising a resonant circuit (RC circuit) resonating at the first undesired frequency (harmonics, ¶0056 and ¶0081-¶0084), wherein the resonant circuit provides a low grounding impedance at the first undesired frequency (first undesired frequency of l000Hz or more is when the impedance drops, ¶0045). Final Action 3. Hobelsberger discloses that a “method is used to detect interlaminar short circuits by examining change patterns of the shaft voltage or, more generally, of the ring fluxes in the stator” wherein “[a] search is preferably carried out for characteristic change patterns in the spectrum of the shaft voltage or of the ring fluxes, more clearly identifying an interlaminar short circuit.” Hobelsberger ¶44. Hobelsberger’s Figure 4 show a preferred measurement arrangement and includes: A generator 1 has a shaft 2 which is borne in bearings 3, 4 and is driven by a turbine 5. The shaft 2 is grounded via two grounding brushes 6, 10 and two grounding modules 7, 11. In this case, two different shaft voltages UW1, UW2 are dropped across the grounding resistance 8, 12. The DE grounding module 7 (DE=drive end) has a low impedance and the RC module 11 (RC=resistor/capacitor) has a high impedance, as a result of which the shaft voltage UW2 tapped of by the grounding current from the RC module will be higher than the shaft voltage UW1 tapped off by the grounding current 9 from the DE module. The two shaft voltages are supplied to the evaluation unit 14. Hobelsberger ¶81 (emphasis added). Appellant contends: First, Hobelsberger does not describe element 11 as comprising a resonant circuit. Although RC (resistor-capacitor) circuits are known to be frequency selective (e.g., filter), Hobelsberger Appeal 2021-004937 Application 15/762,459 6 appears to use “RC module” as purely a naming convention for element 11. Indeed, in the circuit diagram of FIG. 4, element 11 is illustrated with only a resistor or grounding resistance 12. (¶[0081].) FIG. 4 does not depict any capacitor or capacitance within element 11. Furthermore, Hobelsberger does not inherently describe a resonant circuit, let alone a capacitor. Appeal Brief 8. We agree with Appellant that in Hobelsberger’s Figure 4, “element 11 is illustrated with only a resistor or grounding resistance 12,” and, therefore Figure 4 does not show a capacitor. Appeal Brief 8. Furthermore, although Hobelsberger discloses that element 11 in Figure 4 is a “RC module 11 (RC=resistor/capacitor) [that] has a high impedance,” we agree with Appellant that “Hobelsberger appears to use ‘RC module’ as purely a naming convention for element 11. Indeed, in the circuit diagram of FIG. 4, element 11 is illustrated with only a resistor or grounding resistance 12.” Appeal Brief 8. (citing Hobelsberger ¶81 (emphasis added)). “‘For a prior art reference to anticipate in terms of 35 U.S.C. § 102, every element of the claimed invention must be identically shown in a single reference.’” In re Bond, 910 F.2d 831, 832 (Fed. Cir. 1990) (quoting Diversitech Corp. v. Century Steps, Inc., 850 F.2d 675, 677 (Fed. Cir. 1988)). We find Appellant’s argument persuasive of Examiner error because the Examiner has not shown how Hobelsberger’s element 11 discloses a resonant circuit as recited in independent claims 1 and 13. See Hobelsberger Figure 4, ¶81; Appellant’s Figure 3, Specification ¶ 39. Accordingly, we reverse the Examiner’s anticipation rejection of independent claims 1 and 13, as well as, dependent claims 2, 4–7, 9, 10 and 14–20. 35 U.S.C. § 103 Rejections Appeal 2021-004937 Application 15/762,459 7 We reverse the Examiner’s obviousness rejections of dependent claims 3, 8, 11 and 12 for the same reasons as stated above. CONCLUSION Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 2, 4–7, 9, 10, 13–20 102 Hobelsberger 1, 2, 4–7, 9, 10, 13–20 8 103 Hobelsberger, Thanawala 8 11, 12 103 Hobelsberger, Dillig 11, 12 3 103 Hobelsberger, Raith 3 Overall Outcome 1–20 REVERSED Copy with citationCopy as parenthetical citation