Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This action is in response to the amendment filed on 03/23/2026.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1, 3-6, and 11-20 are rejected under 35 U.S.C. 103 as being unpatentable over Dohnal et al. (US Patent Application Publication US 2004/0032699 A1, hereinafter “Dohnal”) in view of Teising et al. (US Patent Application Publication US 2015/0061806 A1, hereinafter “Teising”). Regarding claim 1, Dohnal discloses (see Figure) an electromagnetic induction device comprising: a main tank (1), a magnetic core arranged in the main tank (Examiner’s Note: the transformer of the transformer tank 1 comprising windings 2 and 3 inherently comprise a magnetic core), an On-Load Tap Changer (comprising components in housing 9), OLTC, comprising: an OLTC tank (9) mounted to the main tank, a fine selector (4), a diverter switch (CT, CR), and a customer interface (moveable selector contacts 5 and 6; the customer interacts with the moveable selector contacts and receives the results via 2 and 3); and a barrier (7) separating the main tank from the OLTC tank, wherein the diverter switch is arranged in the OLTC tank (CT, CR, are arranged in 9), and the fine selector and customer interface are arranged in the main tank (4 and 5 and 6 are arranged in 1), and wherein the barrier comprises a plurality of electrical connections (electrical connecting lines 10, 11 are led through oil-tight leadthroughs 13, 14, 15 in the leadthrough plate 7) configured to connect the diverter switch to the fine selector (connecting lines 10, 11 connect CT, CR, to 4). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising).
Regarding claim 3, Dohnal discloses (see Figure) wherein the diverter switch and a load change-over switch (16) are arranged on an OLTC side of the barrier (CT, CR, and 16 are arranged on 9 side of 7). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector and to be arranged on an OLTC side of the barrier, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising) and help prevent the change-over selector from being damaged by the heat of the transformer (see [0009] of Dohnal).
Regarding claim 4, Dohnal discloses (see Figure) wherein a load change-over switch (16) is arranged between the diverter switch and the barrier (16 is arranged between CT, CR and 7). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector and to be arranged between the diverter switch and the barrier, as taught by Teising, because it can help permit the voltage across the regulating
winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising) and help prevent the change-over selector from being damaged by the heat of the transformer (see [0009] of Dohnal).
Regarding claim 5, Dohnal discloses (see Figure) wherein the fine selector and customer interface are arranged on a main tank side of the barrier (4 and 5 and 6 are arranged on 1 side of 7).
Regarding claim 6, Dohnal discloses (see Figure) wherein the fine selector is arranged between the customer interface and the barrier (4 is arranged between 5 and 6, and 7).
Regarding claim 11, Dohnal discloses (see Figure) wherein the electromagnetic induction device is a transformer or a reactor (The Figure is part of a transformer comprising windings 2, 3).
Regarding claim 12, Dohnal discloses (see Figure) wherein the diverter switch and a load change-over switch (16) are arranged on an OLTC side of the barrier (CT, CR, and 16 are arranged on 9 side of 7). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector and to be arranged on an OLTC side of the barrier, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising) and help prevent the change-over selector from being damaged by the heat of the transformer (see [0009] of Dohnal).
Regarding claim 13, Dohnal discloses (see Figure) wherein the fine selector and customer interface are arranged on a main tank side of the barrier (4 and 5 and 6 are arranged on 1 side of 7).
Regarding claim 14, Dohnal discloses (see Figure) wherein the fine selector is arranged between the customer interface and the barrier (4 is arranged between 5 and 6, and 7).
Regarding claim 15, Dohnal discloses (see Figure) wherein the OLTC is a single phase OTLC (tap changer 9 is intended for a single phase of the transformer).
Regarding claim 16, Dohnal discloses (see Figure) a single phase OTLC comprising a fine selector (4), a diverter switch (CT, CR), and a customer interface (output interface connected to 2 and 3), wherein the diverter switch is arranged in the OLTC tank (CT, CR are arranged in 9), and the fine selector and customer interface are arranged in the main tank (4 and 5 and 6 are arranged in 1). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising). Dohnal does not disclose wherein the OLTC is a two phase OTLC. However, Teising teaches (see Fig. 2) wherein the OLTC (12) is a two phase OTLC (comprising the first two Circuit 30s, see [0036] “The tap changing assembly 12 includes three circuits 30, each of which is operable to change taps on a regulating winding 32 for one phase of the transformer.”).
Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the OLTC is a two phase OTLC, as taught by Teising, because it can help provide on-load tap changing for two-phase applications.
Regarding claim 17, Dohnal discloses (see Figure) wherein each diverter switch and a load change-over switch (16) may be mounted to an OLTC side of the barrier (CT, CR, and 16 are arranged on 9 side of 7). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector and to be arranged on an OLTC side of the barrier, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising) and help prevent the change-over selector from being damaged by the heat of the transformer (see [0009] of Dohnal).
Regarding claim 18, Dohnal discloses (see Figure) a single phase OTLC comprising a fine selector (4), a diverter switch (CT, CR), and a customer interface (output interface connected to 2 and 3), wherein the diverter switch is arranged in the OLTC tank (CT, CR are arranged in 9), and the fine selector and customer interface are arranged in the main tank (4 and 5 and 6 are arranged in 1). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising). Dohnal does not disclose wherein the OLTC is a three phase OTLC. However, Teising teaches (see Fig. 2) wherein the OLTC (12) is a three phase OTLC (comprising the three Circuit 30s, see [0036] “The tap changing assembly 12 includes three circuits 30, each of which is operable to change taps on a regulating winding 32 for one phase of the transformer.”). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the OLTC is a three phase OTLC, as taught by Teising, because it can help provide on-load tap changing for three-phase applications.
Regarding claim 19, Dohnal discloses (see Figure) wherein each diverter switch and a load change-over switch (16) may be mounted to an OLTC side of the barrier (CT, CR, and 16 are arranged on 9 side of 7). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal to include a change-over selector and to be arranged on an OLTC side of the barrier, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising) and help prevent the change-over selector from being damaged by the heat of the transformer (see [0009] of Dohnal). Regarding claim 20, Dohnal discloses (see Figure) a transformer comprising: a main tank (1), a magnetic core arranged in the main tank (Examiner’s Note: the transformer of the transformer tank 1 comprising windings 2 and 3 inherently comprise a magnetic core), an On-Load Tap Changer (comprising components in housing 9), OLTC, comprising: an OLTC tank (9) mounted to the main tank, a fine selector (4), a diverter switch (CT, CR), and a customer interface (moveable selector contacts 5 and 6; the customer interacts with the moveable selector contacts and receives the results via 2 and 3); and a barrier (7) separating the main tank from the OLTC tank, wherein the diverter switch is arranged in the OLTC tank (CT, CR, are arranged in 9), and the fine selector and customer interface are arranged in the main tank (4 and 5 and 6 are arranged in 1), and wherein the barrier comprises a plurality of electrical connections (electrical connecting lines 10, 11 are led through oil-tight leadthroughs 13, 14, 15 in the leadthrough plate 7) configured to connect the diverter switch to the fine selector (connecting lines 10, 11 connect CT, CR, to 4). Dohnal does not disclose a change-over selector. However, Teising teaches (see Fig. 3A, 3B, 3C) a change-over selector (36 of Fig. 3B and 40 of Fig. 3C). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the transformer of Dohnal to include a change-over selector, as taught by Teising, because it can help permit the voltage across the regulating winding to be added or subtracted from the voltage across the main winding (see [0036] of Teising).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Dohnal in view of Teising, and further in view of Frotscher et al. (US Patent Application Publication US 2022/0026385 A1, hereinafter “Frotscher”). Regarding claim 2, Dohnal discloses (see Figure) wherein the main tank is filled with a first dielectric liquid (1 is filled with oil, see [0011] “The region lined in grey at the left in the FIGURE shows the oil-filled transformer tank 1”) Dohnal does not disclose wherein the OLTC tank is filled with a second dielectric liquid , and wherein the barrier separates the first dielectric liquid from the second dielectric liquid. However, Frotscher teaches (see Fig. 1) wherein the OLTC tank (S) is filled with a second dielectric liquid (IM’), and wherein the barrier separates the first dielectric liquid (IM) from the second dielectric liquid (the housing of S separates IM from IM’). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of
Dohnal wherein the OLTC tank is filled with a second dielectric liquid , and wherein the barrier separates the first dielectric liquid from the second dielectric liquid, as taught by Frotscher, because it can help dissipate heat of the components of the OLTC tank.
Claims 7-9 are rejected under 35 U.S.C. 103 as being unpatentable over Dohnal in view of Teising, and further in view of Larsson (US Patent Application Publication US 2016/0189859 A1). Regarding claim 7, Dohnal does not disclose wherein the barrier comprises an electrically insulating material. However, Larsson teaches (see Fig. 2c) wherein the barrier (13) comprises an electrically insulating material (see [0044] “The OLTC interface barrier arrangement 13 is at least partly electrically insulating.”). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the barrier comprises an electrically insulating material, as taught by Larsson, because it can help prevent unwanted electrical conduction between the tap changer and the transformer winding, i.e. resulting in arcs or short-circuits.
Regarding claim 8, Dohnal does not disclose wherein the barrier comprises a polymer-based material.
However, Larsson teaches (see Fig. 2c) wherein the barrier (13) comprises a polymer-based material (see [0044] “The OLTC interface barrier arrangement 13 may for example comprise a cellulose-based material, epoxy or polyester.”). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the barrier comprises a polymer-based material, as taught by Larsson, because it can help prevent unwanted electrical conduction between the tap changer and the transformer winding, i.e. resulting in arcs or short-circuits.
Regarding claim 9, Dohnal does not disclose wherein the barrier comprises at least one of glass fiber and epoxy. However, Larsson teaches (see Fig. 2c) wherein the barrier (13) comprises at least one of glass fiber and epoxy (see [0044] “The OLTC interface barrier arrangement 13 may for example comprise a cellulose-based material, epoxy or polyester.”). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the barrier comprises at least one of glass fiber and epoxy, as taught by Larsson, because it can help prevent unwanted electrical conduction between the tap changer and the transformer winding, i.e. resulting in arcs or short-circuits.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Dohnal in view of Teising, and further in view of Shukla et al. (US Patent Application Publication US 2018/0294650 A1, “Shukla”). Regarding claim 10, Dohnal does not disclose wherein the electromagnetic induction device is a high voltage electromagnetic induction device, wherein the high voltage comprises voltages between 36 kV and 145 kV. However, Shukla teaches (see Fig. 2) wherein the electromagnetic induction device (220) is a high voltage electromagnetic induction device (220 is a high voltage OLTC, see [0038] – [0039] “each transformer 220 is an on load tap changing (“OLTC”) transformer.” And “Each cluster transformer 220 can be configured to transform power from an associated cluster network 184 from the second voltage at each DFIG module 100 to a voltage suitable for application to electric grid 240. For example, a cluster network 184 can be operated at a second voltage, such as a medium voltage (“MV”) of 6-13.8 kV, and a grid voltage can be operated at a high voltage (“HV”), such as 132 kV. Each cluster transformer 220 can be configured to step up the voltage from the MV cluster network to the same voltage as the electric grid 240.”), wherein the high voltage comprises voltages between 36 kV and 145 kV (see [0039] “Each cluster transformer 220 can be configured to transform power from an associated cluster network 184 from the second voltage at each DFIG module 100 to a voltage suitable for application to electric grid 240. For example, a cluster network 184 can be operated at a second voltage, such as a medium voltage (“MV”) of 6-13.8 kV, and a grid voltage can be operated at a high voltage (“HV”), such as 132 kV. Each cluster transformer 220 can be configured to step up the voltage from the MV cluster network to the same voltage as the electric grid 240.”). Therefore, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify the electromagnetic induction device of Dohnal wherein the electromagnetic induction device is a high voltage electromagnetic induction device, wherein the high voltage comprises voltages between 36 kV and 145 kV, as taught by Shukla, because it can help provide high-voltage transformation for high-voltage applications.
Response to Arguments
Applicant’s arguments, filed 03/23/2026, with respect to the rejection of claims 1 and 20 regarding “Dohnal does not teach or disclose the claimed change-over selector” have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Teising.
Applicant’s arguments, filed 03/23/2026, with respect to the rejection of claims 1 and 20 regarding “Dohnal does not disclose the claimed customer interface arranged in the main tank” have been fully considered but are not persuasive.
The Figure of Dohnal teaches moveable selector contacts 5 and 6 which are selected and moved by the user, i.e. customer, which provides a customer interface in changing the taps for the desired transformer winding ratio change. Thus, Dohnal teaches a customer interface, and therefore Applicant’s arguments are not persuasive.
Conclusion
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/MONICA LEWIS/ Supervisory Patent Examiner, Art Unit 2838
/JYE-JUNE LEE/Examiner, Art Unit 2838
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