ABB Schweiz AG

Patent Trials and Appeals Board

Dec 23, 2021

2021004937 (P.T.A.B. Dec. 23, 2021)

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

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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.

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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.”).
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Application 15/762,459

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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.

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Application 15/762,459

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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
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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
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Application 15/762,459

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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