| 摘要 |
721,124. Inductive stirrers for electric furnaces. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Aug. 11, 1953, No. 22108/53. Class 39 (3) A stirring winding for melting furnaces or hot metal mixers fed symmetrically from two phases so that the current in one phase has 90 degrees phase displacement with respect to. the current in the other phase comprises five cylindrical coils n1 ... n5 slid on one or more laminated non- slotted straight or curved magnetic yokes 30 arranged below the bottom 10 of the furnace, and the winding of each yoke consists of five successive sections having numbers of turns n1=n5, n2 = n4 and n3 <SP>></SP>= < 2n1. All the coils are of the same length and have the same inner contour, and the coils of the different phases are insulated from each other by insulating pieces 80. The short sides and lower side of the coil are covered by metallic members of low ohmic resistivity to minimize the ineffective part of the magnetic flux. Cooling water or air is circulated between spacer bars in a space between the coils and the yoke. For furnaces having cylindrical or spherical bottoms 10 with a centre angle 2a, the yoke consists of two equal legs 30 forming an angle 180 degrees-αat the junction point, the middle current zone being divided into equal halves 3<SP>1</SP>, 3". For furnaces having plane bottoms, the yoke consists of two equal legs joined in alignment and reinforced, the middle current zone being divided into equal halves. Two parallel sets of windings and yokes of equal length with a reinforcing stay between them may be mounted below the bottom of the furnace, and may carry reinforcing girders of non-magnetic material to support the furnace bottom. The upper surface of the windings may carry a layer of protective refractory material. |
