Magnet core; method for its production and residual current device
View Patent ↗A magnet core ( 1 ) that is suitable for use in a fault current circuit breaker and that is made of a helically wound, magnetically soft band has a top ( 4 ) and a bottom ( 5 ), the top ( 4 ) and the bottom ( 5 ) being formed by side surfaces ( 16 ) of the magnetically soft band. The magnet core ( 1 ) is fixed in a protective housing ( 6 ), and there is a contact cement ( 11 ) between the bottom ( 5 ) of the magnet core ( 1 ) and an inside wall ( 10 ) of the housing for fixing the magnet core ( 1 ).
1. A magnet core assembly, comprising:
a magnet core formed from a magnetically soft band that is helically wound to form a plurality of band layers separated by intermediate spaces, and having side surfaces thereof, wherein the magnet core comprises a top and a bottom, wherein the top and the bottom are formed by a side surface of the magnetically soft band;
a protective housing comprising an inside wall disposed around the magnet core, and within which the magnet core is fixed; and
a tacky contact cement having an elongation at tear ε R >250% disposed between the bottom of the magnet core and the inside wall of the protective housing for fixing the magnet core therein.
2. The magnet core assembly according to claim 1 , wherein the contact cement has an elongation at tear ε R , such that ε R >450%.
3. The magnet core assembly according to claim 2 , wherein the contact cement has an elongation at tear ε R , such that ε R >600%.
4. The magnet core assembly according to claim 1 , wherein the contact cement has a glass transition temperature T g , such that T g <0° C.
5. The magnet core assembly according to claim 4 , wherein the contact cement has a glass transition temperature T g , such that T g <−20° C.
6. The magnet core assembly according to claim 5 , wherein the contact cement has a glass transition temperature T g , such that T g <−30° C.
7. The magnet core assembly according to claim 1 , wherein the contact cement has a melting point T s , such that T s >180° C.
8. The magnet core assembly according to claim 1 , wherein the contact cement comprises an acrylate polymer.
9. The magnet core assembly according to claim 1 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t, such that t<2 mm.
10. The magnet core assembly according to claim 9 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t, such that t<0.5 mm.
11. The magnet core assembly according to claim 10 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t, such that t<0.01 mm.
12. The magnet core assembly according to claim 1 , wherein the magnetically soft band is nanocrystalline.
13. The magnet core assembly according to claim 1 , wherein the magnetically soft band is crystalline.
14. The magnet core assembly according to claim 1 , wherein the magnetically soft band is amorphous.
15. The magnet core assembly according to claim 1 , wherein the magnetically soft band consists essentially of the following alloy composition:
Fe a Co b Cu c Si d B e M f X g
in which M is at least one of the elements V, Nb, Ta, Ti, Mo, W, Zr, and Hf, and X is at least one of the elements P, Ge and C; a, b, c, d, e, f, and g are given in atomic percent, are such that 0≦b≦45; 0.5≦c≦2; 6.5≦d≦18; 5≦e≦14; 1≦f≦6; g<5; d+e>16; and a+b+c+d+e+f+g=100, wherein cobalt can be replaced in whole or in part by nickel; and
commercially common impurities of raw materials and the melt.
16. The magnet core assembly according to claim 1 , wherein the magnet core has a saturation magnetostriction constant λ s of λ s <15 ppm.
17. The magnet core assembly according to claim 1 , wherein the magnet core has a ratio of remanent induction to saturation induction B R /B S such that B R /B S >45%, and has a maximum permeability μ max such that μ max >250,000.
18. The magnet core assembly according to claim 1 , wherein the magnet core has a ratio of remanent induction to saturation induction B R /B S such that B R /B S >50% and has a maximum permeability μ max such that μ max >150,000.
19. The magnet core assembly according to claim 1 , wherein the magnet core has a ratio of remanent induction to saturation induction B R /B S such that B R /B S >2% and has a maximum permeability μ max such that μ max >5,000.
20. A method for producing a magnet core assembly according to claim 1 , comprising:
providing a magnet core wound from a magnetically soft band to form a plurality of band layers separated by intermediate spaces, and having side surfaces thereof, wherein the magnet core comprises a top and a bottom, wherein the top and bottom are formed by a side surface of the magnetically soft band;
providing a protective housing comprising an inside wall, and adapted for holding the magnet core;
applying a contact cement to the inside wall of the protective housing, wherein the contact cement forms a tacky film on its surface;
inserting the magnet core into the protective housing, such that the bottom of the magnet core contacts and adheres to the contact cement.
21. The method according to claim 20 , whereby the contact cement comprises an acrylate polymer.
22. The method according to claim 20 , wherein the applying of the contact cement comprises applying an aqueous dispersion of the contact cement to the inside wall of the protective housing.
23. The method according to claim 20 , wherein the applying of the contact cement comprises applying an organic solution of the contact cement to the inside wall of the protective housing.
24. The method according to claim 20 , wherein the contact cement has a viscosity ν such that ν<20 Pa·s during the inserting of the magnet core into the protective housing.
25. The method according to claim 20 , wherein the contact cement has a solid content of more than 30 percent by weight during the inserting of the magnet core into the protective housing.
26. The method according to claim 20 , wherein the contact cement has a minimum film formation temperature T F such that T F <0° C.
27. The method according to claim 20 , wherein the contact cement has an elongation at tear ε R such that ε R >600%.
28. The method according to claim 20 , wherein the contact cement has a glass transition temperature T g such that T g <−30° C.
29. The method according to claim 20 , wherein the contact cement has a melting point T s such that T s =180° C.
30. The method according to claim 20 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t such that t<2 mm.
31. The method according to claim 30 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t such that t<0.5 mm.
32. The method according to claim 31 , wherein the contact cement penetrates into the intermediate spaces up to a penetration depth t such that t<0.01 mm.
33. The method according claim 20 , further comprising hot air drying the contact cement after the applying to the inside wall of the protective housing.
34. The method according to claim 20 , further comprising infrared drying the contact cement after the applying to the inside wall of the protective housing.
35. The method according to claim 20 , wherein the inserting of the magnet core into the protective housing occurs when the contact cement has not yet set under the film on its surface.
36. The method according to claim 20 , further comprising heat treating the magnet core before the inserting into the protective housing.
37. The method according to claim 36 , wherein said heat treating is done in the absence of a magnetic field.
38. The method according to claim 36 , wherein said heat treating is done at a temperature T such that 505° C.≦T≦600° C.
39. The method according to claim 38 , wherein said heat treating is done fully or intermittently in a magnetic field.
40. A fault current circuit breaker comprising a magnet core assembly according to claim 1 .