GB457021A - Improvements in and relating to circuit arrangements for varying the phase position of the grid potential of controlled electric discharge devices - Google Patents

Abstract

457,021. Converting. SIEMENS-SCHUCKERTWERKE AKT.-GES., Siemensstadt, Berlin. July 3, 1936, No. 18572. Convention date, July 4, 1935. [Class 38 (ii)] A phase-shifting circuit by means of which the voltage Us, Fig. 1, may be shifted through substantially 180‹ and its magnitude remain unchanged comprises in series with an inductance 40 a parallel connected condenser 63 and a variable resistance 62, the impedance of the condenser being twice that of the inductance. Phase shift is obtained by varying the resistance. In a modification, the inductance and condenser are interchanged. The inductance may be a saturated transformer. Fig. 5 shows a circuit arrangement comprising saturated transformers I-VI for producing grid potentials built up from a number of unsymmetrical peaks. The primary windings are connected in star through resistances 62 across which condensers 63 are connected in delta. Variation of the phase of the grid potentials is effected by adjustment of the resistances 62. To obtain automatic regulation of the output voltage of a rectifier the resistance may be thermo-negative and have a heating winding supplied with current proportional to the rectified potential. In a modification of this, four thermo-negative resistances may be connected in a bridge with the voltage to be regulated or a voltage proportional to it connected across one of the diagonals. In a modification of this, thermopositive resistances are connected in bridge form with the difference between a standard and the variable voltage applied to a diagonal. In a further modification, a Grõtz connection of rectifiers is connected in circuit with the variable voltage to be regulated connected across a diagonal.