GB499411A - Electric converters - Google Patents

Abstract

499,411. Converting ; automatic regulation. SIEMENS BROS. & CO., Ltd., GRINSTED, W. H., and DOUBLE, H. S. July 29, 1937, No. 21006. [Classes 38 (ii) and 38 (iv)] In a converting arrangement, particularly for supplying D.C. to a telephone installation from an A.C. source, and comprising inductive windings (which may be smoothing chokes or saturating windings on regulating chokes) in series with the output leads, there is provided in shunt with the windings a circuit of such a nature that a sudden change in load current causes a change in the distribution of current between the windings and the shunt circuit tending to minimise the transient effect of the sudden change in load on the output voltage. In the arrangement shown in which regulating chokes I on the input side of the converter (comprising the transformer TRA and rectifier REB) are provided with saturating windings II, III connected respectively in series with the load and across the output terminals of a resistance bridge BB the input terminals of which are connected across the output terminals of the rectifier, the shunt circuit for the windings II comprises a choke CHT of relatively high inductance in series with a variable resistance YB. The latter enables the regulating characteristic of the chokes I as determined bv the windings II to be adjusted whilst the choke CHT, owing to its relatively large inductance, causes, when the load current suddenly changes, a relatively large change in the current in the windings II connected in parallel therewith and thus operates to minimise the voltage transient at the rectifier output terminals. Similarly in the case of a smoothing choke CHS connected in series with the output leads, a shunt circuit may be provided. In this case the shunt circuit comprises a rectifier, preferably of the dry plate type, the resistance of which varies so that its shunting effect comes into play or is increased when large non-alternating voltage components appear across the choke on a sudden change in load current. Specifications 388,772, 430,247, and 473,281 are referred to.