# US 9,437,356 B2 · Medium frequency transformer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,356 B2 - Document ID: US9437356B2 - Status: Granted - Kind: B2 - Application number: 13/935,141 - Filed: 2013-07-03 - Published: 2014-06-12 - Granted: 2016-09-06 - Earliest claimed: 2012-08-10 - Assignees: STS Spezial-Transformatoren-Stockach GMBH & Co. KG - Applicants: STS Spezial—Transformatoren—Stockach GmbH & Co. KG - Inventors: Wilhelm Krämer; Christoph Gulden - Web page: https://patentgrep.com/patent/US9437356B2 ## CPC - H01F 5/06: Insulation of windings - H01F 27/02: Casings - H01F 27/06: Mounting, supporting, or suspending transformers, reactors, or choke coils {not being of the signal type} - H01F 27/08: Cooling (heat-transfer elements F28F); Ventilating (structural details of casings H01F27/02) - H01F 27/10: Liquid cooling - H01F 27/321: {using a fluid for insulating purposes only} - H01F 30/10: Single-phase transformers (H01F30/16 takes precedence) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract The invention concerns a medium frequency transformer with a housing, in which numerous winding chambers, having primary and secondary windings, are disposed, wherein the housing is filled, at least partially, with an insulating liquid. The transformer is distinguished in that numerous winding chambers, filled with the insulating liquid, are disposed in the housing, and at least one winding is disposed in each winding chamber, such that, for the most part, only the windings are surrounded by the insulating medium. Preferably the winding chambers are sealed and separated from one another by means of insulating separating walls, wherein the windings are positioned and fixed in place in the winding chambers, and the winding chambers are filled with the insulating liquid. Between the windings there are thus, according to the invention, at least two insulating barriers, which function simultaneously and consist of solid matter insulation in the form of housing and separating walls, and the insulating liquid. ## Claims ### Claim 1 A medium frequency transformer, comprising a sealed housing made of an insulating material, having a plurality of winding chambers for accommodating a plurality of windings, comprising a primary winding and a secondary winding, and at least one core, wherein a liquid or a gas insulating medium is placed in the winding chambers of the sealed housing which fills the winding chambers, provided with a plurality of bushing holes to the winding chambers, and a plurality of intakes and discharges for the insulating medium, and wherein the winding chambers are formed such that only the windings are surrounded by the insulating medium, whereas the core is disposed outside of the sealed housing filled with the insulating medium. ### Claim 2 (depends on 1) The medium frequency transformer according to claim 1, wherein the winding chambers are sealed and separated from one another by a plurality of insulating housing walls and separating walls, the windings are positioned in the winding chambers and fixed in place therein, and the winding chambers are filled with the liquid or the gas insulating medium. ### Claim 3 (depends on 1) The medium frequency transformer according to claim 1, wherein the housing is designed as at least a two-part housing prior to the assembly, comprising a transformer housing a cover housing, and a plurality of junction boxes and seals and lids that can be attached thereto. ### Claim 4 (depends on 1) The medium frequency transformer according to claim 1, wherein the windings are axially and radially fixed in place in the winding chambers. ### Claim 5 (depends on 2) The medium frequency transformer according to claim 2, wherein the housing walls and the separating walls exhibit a plurality of integrated projections or separate spacing elements through which the windings are positioned and fixed in place in the winding chambers, wherein the windings are positioned and fixed in place through a plurality of rigid or elastic components in the winding chambers. ### Claim 6 (depends on 2) The medium frequency transformer according to claim 2, wherein the transformer housing comprises the housing walls and the separating walls, and the cover housing exhibits a plurality of grooves, in which a plurality of outer walls and the separating walls engage in a sealing manner when sealing the transformer housing. ### Claim 7 (depends on 3) The medium frequency transformer according to claim 3, wherein, for connecting the transformer housing to the cover housing and the lids of the junction boxes, the transformer further comprises an attachment means with spring elements, which connect the cover housing and the lids to the transformer housing in a self-tightening manner. ### Claim 8 (depends on 1) The medium frequency transformer according to claim 1, further comprising, in the housing, a plurality of liquid and solid matter insulated, and electro-conductive, bushings, with which a plurality of ends of the windings, and a plurality of outer connections for the windings are electrically connected. ### Claim 9 (depends on 1) The medium frequency transformer according to claim 1, wherein a plurality of junction lids are disposed on the housing and connected to the housing in a compressed, and without gaps, insulating manner, and form insulated, or sealed, bushings for the connections of the windings. ### Claim 10 (depends on 1) The medium frequency transformer according to claim 1, wherein the at least one core is tensioned on a corner configuration and a recess of the housing and is retained and separated from the housing by means of a tensioning elastic intermediate layer. ### Claim 11 (depends on 1) The medium frequency transformer according to claim 1, wherein the at least one core is retained radially and axially by means of a plurality of tensioning straps and tensioning frames, and the at least one core is provided with ribs on the sides of a plurality of junction boxes and a plurality of outer surfaces of a core package for bridging components and thus to increase the electrical surge voltage resistance of the cores on the outside. ### Claim 12 (depends on 1) The medium frequency transformer according to claim 1, wherein the at least one core is grounded by means of a plurality of electrical connections to a plurality of tensioning straps, in order that a galvanic potential separation is obtained between an outer high-voltage connection and a low-voltage connection of the transformer. ### Claim 13 (depends on 1) The medium frequency transformer according to claim 1, wherein a plurality of material recesses are provided on a plurality of forms on the housing, for attaching the at least one core. ### Claim 14 (depends on 1) The medium frequency transformer according to claim 1, wherein an axially disposed intermediate insulation is disposed between the at least one core. ### Claim 15 (depends on 1) The medium frequency transformer according to claim 1, wherein a plurality of tensioning frames for accommodating the least one core is designed such that at least a partial cooling of the at least one core by means of the insulating liquid or through a plurality of cooling bodies integrated therein. ### Claim 16 (depends on 1) The medium frequency transformer according to claim 1, wherein the primary winding comprises two or more layers, wherein a sub-winding with an intermediate insulation is sandwiched between the layers of the primary winding. ### Claim 17 (depends on 1) The medium frequency transformer according to claim 1, wherein the winding chambers exhibit at least an intake and a discharge for the insulating liquid, wherein the insulating liquid is substantially conveyed in a uniform manner through the winding chambers. ### Claim 18 (depends on 17) The medium frequency transformer according to claim 17, wherein the intake of one winding chamber is connected to the discharge of another winding chamber via a hydraulic bridge connection wherein the hydraulic bridge is either integrated in the housing or is designed as a separate component and connected to the housing. ### Claim 19 (depends on 17) The medium frequency transformer according to claim 17, wherein the intakes and discharges in the housing comprise angled channels. ### Claim 20 (depends on 17) The medium frequency transformer according to claim 17, wherein the intakes and the discharges for the insulating liquid comprise hydraulic or pneumatic couplings. ### Claim 21 (depends on 1) The medium frequency transformer according to claim 1, wherein the housing of the transformer exhibits a plurality of fittings of uniform size on an upper surface and a lower surface, such that numerous such transformers can be connected, insulated in all layers, and be stacked directly on top of one another. ### Claim 22 (depends on 1) A plurality of medium frequency transformers according to claim 1 combined to form a plurality of cascades or partial cascades, and these are combined such that they form a collective housing with a collective configuration in multiple-units. ### Claim 23 (depends on 17) The medium frequency transformer according to claim 17, wherein the intake and the discharge for the insulating liquid are disposed on the housing diagonally opposed to one another. ### Claim 24 (depends on 19) The medium frequency transformer according to claim 19, wherein the angled channels are placed axially in the housing and enter the winding chambers radially. ### Claim 25 (depends on 20) The medium frequency transformer according to claim 20, wherein the couplings comprise self-sealing quick couplings made of electrically insulating material. ### Claim 26 (depends on 2) The medium frequency transformer according claim 2, wherein the housing is designed as a least two-part housing prior to the assembly, comprising a transformer housing, a cover housing, and a plurality of junction boxes and seals and lids that can be attached thereto. ### Claim 27 (depends on 26) The medium frequency transformer according to claim 26, wherein the transformer housing and its housing walls and separating walls are glued or cast to the cover housing.