Patent GB-190919090-A (GB)
Title: Improvements in or relating to Means for Rectifying Electric Currents.
Inventor: MURPHY THOMAS JOSEPH
IPC: H02M1/04
Filed: 1909-08-19
Granted: 1910-08-18
Abstract: 19,090. Murphy, T. J. Aug. 19. Converting alternating and direct currents. - In a rectifying system, a high resistance in the alternating- current circuit is reduced by a highpotential current controlled by an electric valve, of the type described in Specification 3410/10. T h e secondary of the transformer 31 is connected through the coils 11, 12 to graphite blocks 7, 10, which with the blocks 8, 9 form two sparkgaps. These electrodes are mounted on pillars, and the outer two 7, 10 may be adjusted by thumb-screws to vary the lengths of the spark gaps. The transformer 31 is connected to the electrodes 8, 9 by the lead 15, and to the electrodes 7, 10 by the leads 16, 17, which include electro-magnets 11, 12. The spark-gaps are shunted by high resistances 131, and the middle pair of electrodes are connected to one side of the condenser 18, which is connected across the secondary 19 of the step-up transformer 20 through choking-coils 21, 22. The wires 60, 64, preferably of platinum or German silver, of the rectifiers are connected to the secondaries 62, 65 of the transformer 61. By this means, the wires receive a current to raise their temperatures above those of the disks 63, 66. The disks are preferably made of aluminium. The wire 60 and disk 66 are connected to the electrodes 7, 10. A switch 120 is connected in the primary circuit of the transformer 20, and is provided with a resistance 143 and inductance 142. As the switch arm is moved from left to right, resistance is put in the circuit and inductance is taken out. When the condenser reaches a potential sufficient to spark across one of the rectifiers, it will also spark across one of the gaps 7, 8 or 9, 10. Current will then flow in the main circuit in such a direction as to continue the spark. The next half - wave of the alternating current passes across the other spark-gap, and the current in the circuit 15 remains in the same direction as before. The apparatus is shown arranged for the charging of a storage battery 6, and, in order to prevent discharge, an air or electromagnetic blast is employed to blow out the arcs across the electrodes 7, 8, 9, 10. If the electro-magnets 11, 12 are used, they are provided with laminated T-shaped poles, and the windings are divided into two parts. The electro-magnets 90, 91 control the circuit of the transformer 20, the first one 90 acting when energized to close the circuit, and the second to open the circuit. The armatures 92, 94 carry suitable weights 93, 95, which may be adjusted by means of screws. The windings 90, 91 may be shunted by resistances, and the armature 92 is arranged to operate when a small current flows in the winding 90. When the battery has been charged up to a certain potential, the current in the winding 91 is large enough to operate the armature 94 to break the charging- circuit. The switch 120 has a spring arm 125 mounted on a rigid arm 126. The arm 125 carries a contact 124, which works over the resistance contacts 123 and the inductance contacts 122, the latter being interspersed with insulating buttons 128.