GB916810A - Converter installation for heavy currents with semi-conductor rectifier elements - Google Patents

Abstract

916,810. Semi-conductor rectifier arrangements. SIEMENS SCHUCKERTWERKE A.G. May 28, 1959 [July 10, 1958], No. 18279/59. Class 37. A rectifier arrangement includes input and output conductors having respective portions which intersect or surround a common axis, and more than two PN junction rectifiers symmetrically distributed about the axis and connected in parallel between the input and output conductors by symmetrically disposed leads, the arrangement being such that the current is equally divided between the rectifiers. In a typical arrangement, Fig. 1, the rectifiers 1-8 are distributed in parallel leads 9-20 extending between conductive rings 25, 26, attached by radial leads to the input and output conductors 35, 45, respectively. The latter may extend from the arrangement in opposite directions, or in the same direction if one of them is a hollow cylinder enclosing the other. To allow closer packing of the rectifiers they may be arranged at differing distances from the two rings. In one arrangement two rectifiers are arranged in each parallel lead, the leads being interconnected between the rectifiers by two conductive rings. In alternative arrangements the leads from the input and output conductors to the rings lie on conical surfaces, and the rectifiers may be mounted in leads lying on a frusto-conical surface between rings of unequal diameters. Several arrangements of the above types may be connected in series by interconnection of the respective input and output conductors of adjacent arrangements or may be mounted one within the other and parallel connected. Alternatively the arrangements may form part of a large assembly in which the relation between arrangement and assembly is the same as that between individual rectifiers and the arrangement. In the practical layout shown in Figs. 8 and 9 the rectifiers 58 are screwed into or bolted to hexagonal metal ring 57, mounted on a base ring 59 via insulating ring 36. The rectifier casings form one electrode thereof, the other electrodes having flexible extensions 67 passing through apertures in the flanged insulating ring 65 to a further metal ring 66 connected by radial metal plates to the output conductor 76. Input conductor 75 arranged within the latter is connected by radial plates 69-74 (Fig. 9) to the mounting-ring 57. Cooling fins or cylinders 86, 87 are provided on the radial plates, and if space allows, on the inside of the mounting ring, air being blown or sucked past them by fan 63. Transformers formed by flexible leads 67 and toroidal iron cores 81 on the insulating ring form part of a system guarding against excessive forward or reverse currents. Series resistor-capacitor arrangements mounted on rings 36 are connected in parallel with the individual rectifiers as described in Specification 855,725 to eliminate undesirable effects due to hole storage. A variable reactor 82 with controlled premagnetization core 82 controls the output current by varying the instant in each positive half-cycle at which the rectifiers begin to take current. Input conductor 75 forms the working winding of the reactor and 84 the control winding. In an otherwise similar arrangement the assembly of rings 57, 65, 66 is duplicated, the ring 66 of one set being electrically connected to ring 57 of the other to form a series connection between input and output. Six rectifier assemblies 102-107 of the above construction (Fig. 11) mounted on a tubular duct 108 form the six arms of a three-phase rectifier bridge, cooling air from a common fan 109 being directed through the individual arrangement by baffles. In another three-phase bridge arrangement, Fig. 15, two rows of three rectifier assemblies 124-126 are mounted on an air chest supplied by fans 120-121.