Composite Material for a Transformer

Abstract

A composite material, in particular for use in a transformer comprising a first and a second grain-oriented electric strip layer and a polymeric layer arranged therebetween is disclosed. The polymeric layer includes a crosslinked acrylate-based copolymer of high molecular weight and has a layer thickness in the range from 3 to 10 μm.

Claims

1. A composite material for use in a transformer, the composite material comprising: a first grain-oriented electric strip layer and a second grain-oriented electric strip layer; and a polymeric layer arranged between the first grain-oriented electric strip layer and the second grain-oriented electric strip layer, wherein the polymeric layer comprises a crosslinked acrylate-based copolymer of high molecular weight and has a layer thickness in the range from 3 to 10 μm.

2. The composite material according to claim 1, wherein the crosslinked high molecular weight acrylate-based copolymer comprises a copolymerized mixture of at least: at least one of an alkyl acrylate ester monomer unit and alkyl methacrylate ester monomer unit, wherein each unit has an alkyl group with 1 to 12 carbon atoms; a glycidyl monomer unit; an unsaturated carboxylic acid monomer unit; and a crosslinker.

3. The composite material according to claim 2, wherein the copolymerised mixture has a mean molar mass in the range from 500 to 1500 kDa.

4. The composite material according to claim 1, wherein the first grain-oriented electric strip layer and the second grain-oriented electric strip layer have a layer thickness in the range from 50 to 1500 μm.

5. The composite material according to claim 1, wherein the first grain-oriented electric strip layer and the second grain-oriented strip layer have an insulation layer with a layer thickness in the range from 0.5 to 2 μm.

6. A method for continuously producing a composite material, the method comprising the steps of: providing a first grain-oriented electric strip layer; coating the first grain-oriented electric strip layer with a polymeric agent comprising an acrylate-based copolymer of high molecular weight and a crosslinker; heating the coated first grain-oriented electric strip layer; providing and heating a second grain-oriented electric strip layer; and laminating the first and the second grain-oriented electric strip layers to obtain a composite material having a polymeric layer comprising a crosslinked acrylate-based copolymer of high molecular weight having a layer thickness in the range from 3 to 10 μm.

7. The method according to claim 6, wherein the acrylate-based copolymer of high molecular weight is formed from a copolymerised mixture of: at least one of an alkyl acrylate ester monomer unit and an alkyl methacrylate ester monomer unit, wherein each unit has an alkyl group with 1 to 12 carbon atoms; a glycidyl monomer unit; and an unsaturated carboxylic acid monomer unit.

8. The method according to claim 6, wherein the first and the second grain-oriented electric strip layers are heated to a temperature in the range from 150 to 250° C.

9. A composite material produced by the method according to claim 6.

10. The composite material according to claim 9, having a loss at P1.7; 50 Hz in the range from 0.60 to 1.0 W/kg and/or a field strength at J800 in the range from 1.88 to 1.96 T determined in accordance with DIN EN 60404-2.

11. (canceled)

12. (canceled)

13. A method for producing an iron core for a transformer, the method comprising the steps of: providing a composite material comprising: a first grain-oriented electric strip layer and a second grain-oriented electric strip layer; and a polymeric layer arranged between the first grain-oriented electric strip layer and the second grain-oriented electric strip layer, wherein the polymer layer comprises a crosslinked acrylate-based copolymer or high molecular weight and has a thickness in the range from 3 to 10 82 m, separating a plurality of lamellae from the composite material; and connecting the lamellae to an iron core.

14. The method according to claim 13, wherein the lamellae are connected by a thermally activatable adhesive.

15. (canceled)

16. An iron core for a transformer produced by the method according to claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In the following the invention will be explained in more detail with reference to drawings. These show in detail:

[0076] FIG. 1 a first embodiment variant of the composite material according to the invention,

[0077] FIG. 2 a second embodiment variant of the composite material according to the invention,

[0078] FIG. 3 a multilayer structure using the composite material according to the second embodiment variant and

[0079] FIG. 4 a process diagram for the production of the composite material according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0080] In FIG. 1, a three-layer structure of a composite material 1 according to the invention and according to a first embodiment is shown. The composite material 1 comprises a first electric strip layer 2, a second electric strip layer 4 and a polymeric layer 3 arranged therebetween.

[0081] FIG. 2 shows a second embodiment variant of the composite material 5 according to the invention with a first and second electric strip layer 2, 4 and a polymeric layer 3 arranged therebetween. On the opposite side to polymeric layer 3, the two electric strip layers 2, 4 respectively have an insulation layer 6. According to a preferred embodiment variant, this is formed by a thermally activatable adhesive.

[0082] In FIG. 3, a multilayer structure 7 is shown using the composite material 5 according to the second embodiment variant. The individual layers of the composite material 5 are in this case arranged one above the other to form a stack. If the insulation layer 6 is formed by a thermally activatable adhesive, the multilayer structure 7 has a homogeneous insulation layer 6 between the individual lamellae (not shown).

[0083] FIG. 4 shows a process diagram for the continuous production of the composite material 1, 5 according to the invention by means of a strip coating system 10. The system 10 has a first and a second strip unwinding station 11, 12, with which a first and second grain-oriented electric strip layer 2, 4 is provided. Furthermore, the system 10 has a stapling device 13 and a first and second strip accumulator 14, 20, which allow a change of a coil without requiring the process to be interrupted. If necessary, the first electric strip layer 2 is first added to a pretreatment stage 15 in order to free the surface of the electric strip layer 2 from adhering dirt particles and oils. Subsequently, the polymeric agent (not shown) is applied on one side via an applicator roller 16. The electric strip layer 2 coated with the polymeric agent then passes through a 2-zone furnace 17, in which the applied coating is pre-dried at 100-120° C. In this case, the solvent is removed. In the second zone of the furnace 17, the electric strip layer 2 is heated to the PMT (170-190° C.). Furthermore, a second electric strip layer 4 is provided by the second unwinding station 12 and first fed to a heating station 17, in which the second electric strip layer 4 is likewise heated to the PMT. In a duplicating station 18, the two electric strip layers 2, 4 are laminated together under a pressure of 5 kN and at a temperature of 150-170° C. to form the composite material 1, 5. Subsequently, the still-hot composite material 1, 5 passes through a cooling station, where it cools to room temperature and is then wound into a coil on a strip winding station 21.

LIST OF REFERENCE NUMERALS

[0084] 1 Composite material [0085] 2 First electric strip layer [0086] 3 Polymeric layer [0087] 4 Second electric strip layer [0088] 5 Composite material [0089] 6 Insulation layer [0090] 7 Multilayer design [0091] 10 Strip coating system [0092] 11 Strip unwinding station [0093] 12 Strip unwinding station [0094] 13 Stapling device [0095] 14 Strip accumulator [0096] 15 Pretreatment stage [0097] 16 Applicator roller [0098] 17 Heating station [0099] 18 Duplicating station [0100] 19 Cooling station [0101] 20 Strip accumulator [0102] 21 Strip winding station