GB167222A - Improvements in and relating to mercury vapor arc devices - Google Patents

Abstract

167,222. Igranic Electric Co., Ltd., (Cutler-Hammer Manufacturing Co.). April 22, 1920. Vapour apparatus, arrangements of.-In a rectifier having a mercury cathode covered with a finely-divided coating of highly refractory material, the arc may be started and maintained at different values of the impressed potential wave by means of an auxiliary anode, so as to produce rectified current impulses of different shapes. The auxiliary anode 4, Fig. 1, is connected with the cathode 2 through a condenser 7 and the secondary winding of a step-up transformer, the primary of which is connected across the supply mains L with the main anode 3, and through a battery 6 representing the load with the cathode. Curves are shown to illustrate the variations produced in the rectified impulses by including capacity, inductance or resistance in the circuit of the auxiliary anode. In the arrangement shown in Fig. 7, the starting potential is applied between the auxiliary anode 20 and the main anode 19 by means of a transformer T. The full-wave rectifier shown in Fig. 8 comprises two main anodes 27, 28 connected across an autotransformer T<1>, and an auxiliary anode 29 in series with a condenser or resistance 32 and the secondary of a step-up transformer T<2>, which may be cut out after starting. The battery 31, representing the load, is connected between the cathode 26 and the auto-transformer. In the arrangement shown in Fig. 9 for controlling a motor A, the potentials applied between the main anodes 54, 55 and auxiliary anodes 56, 57 of two rectifiers 35, 36 are controlled by thermionic valves 39, 40 and a tachometer driven by the motor. The anodes 47, 48 of the valves are connected with the main anodes 57, 58, and the valve cathodes 43, 44 are connected with the auxiliary anodes 56, 57 through condensers 41, 42 and the secondary windings of transformers T<4>, T<5>, the primaries of which are connected across supply mains through a resistance. The control grids 49, 50 are connected through a battery 51 and the armature of the tachometer 52 with a resistance 53 between the cathode-heating batteries 45, 46. The tachometer is driven by the motor so that the potential on the grids, and consequently the potential supplied by the valves to the anodes of the rectifiers, vary with the speed of the motor, with the result that the speed is maintained constant.