GB704864A - Improvements in rectifier type power supply systems - Google Patents

Abstract

704,864. Automatic control systems for rectifiers. WESTERN ELECTRIC CO., Inc. July 4, 1950 [July 6, 1949], No. 16644/50. Class 38 (4) Two similar rectifying systems supply a load in parallel, there being controls which keep the output current constant and shared equally between the systems. Several rectifiers of the dry metal or discharge tube type may be connected in series in each system. The voltage drop across a resistance 15 carrying the load current, through direct coupled amplifiers 57, 57a varies the resistances of pairs of valves 12, 13 and 12a, 13a in the outputs from the two rectifiers in such sense that they tend to restore the current to its set value (fine control). The input A.C. voltage to each rectifier is controlled by the input servocontrol which comprises a variable auto transformer controlled by a servomotor operated in one direction or the other according as the value of a variable inductance 44 (44a) varies above or below a given value. The values of these inductances 44, 44a are controlled by the currents in windings 39, 39a which are connected in shunt to the series valves 12, 13 and 12a, 13a (main control of the output current) and by the load currents of the other rectifier systems passing through windings 17, 17a (to control the load sharing). The various constant D.C. voltages for operation of the direct coupled amplifiers are derived through a subsidiary rectifier (RECT) and three voltage regulator tubes. The various parts of the circuit are described in detail with reference to Figs. 1a, lb, 1c (not shown) where the following additional features are shown: one winding of each two phase servomotor is energized between the mid point of the input autotransformer and the junction of a fixed inductor and the variable inductor 40, (40a) ; limit switches stop each servomotor from overrunning at each end of its travel; after operation of a switch manual control may replace automatic control ; two remotely controlled relays allow the driving of the servomotor to its lower limit, one whether or not the system is set for manual control and the other only when it is not. In a modification, the series regulator valves are connected in the output leads, Fig. 3b (not shown). Specification 704,940 is referred to.