GB389801A - Improvements in or relating to alternating electric current regulating systems - Google Patents

Abstract

389,801. Automatic regulation. SOC. ANON. GAUMONT-FRANCO-FILMAUBERT, 3, Rue Caulaincourt, Paris. June 18, 1931, No. 17712. Convention date; July 9, 1930. Void [Published under Sect. 91 of the Acts]. [Classes 35 and 38 (iv).] Systems depending on static transformers ; exciting.-A variable A.C. voltage is rendered constant by means of a reactance coil or transformer winding associated with a winding adapted to modify the co-efficient of selfinduction or the ratio of transformation. This device may be combined with resistance elements, which change their resistance with the voltage applied to them and so amplify the effect. Various applications are described. According to the arrangement shown in Fig. 4, the varying voltage is applied to terminals 11, 12 and a steady voltage is obtained at the output terminals of a transformer 21. Variations of the input voltage, applied through the rectifier 16 and resistance element 23 of the kind referred to, vary the saturation of a reactance coil 18 in series with a boosting transformer 20. A coil 17a subject to an auxiliary control voltage may vary the action of the apparatus. In a modification the reactance coil is connected across the transformer 15 in series with a resistance and the varying potential difference across the reactance is applied through a rectifier to a saturating winding on a reactance coil in series with the primary of the transformer 21. Auxiliary coils may be applied to both reactance coils. The transformers may be dispensed with. Fig. 6 shows an arrangement for maintaining motor speed constant. The strength of the field winding 43 depends upon the impedance of a reactance coil 47 which is varied by a saturating winding 51 in series with an amplifying resistance 72 in dependences on the voltage applied to the armature terminals of the motor. The excitation is derived from A.C. tappings on the armature, and a rectifier and amplifying resistance 52 are included in the field circuit. A similar arrangement is described for regulating the voltage of a D.C. generator having an exciting circuit derived from armature tappings and a transformer. A reactance coil in the exciting circuit has its saturation varied by a winding supplied through a rectifier from the potential difference across a reactance coil fed from this transformer through a resistance ; the saturation of this second reactance coil is controlled by the output voltage through an amplifying resistance.