Patent GB-102977-A (GB)
Title: Improvements in Apparatus for Transforming, and especially for Rectifying, Alternating or Polyphase Currents.
Inventor: HARTMANN JULIUS FREDERIK GEORG
IPC: H02M1/30
Filed: 1916-12-30
Abstract: 102,977. Hartmann, J. F. G. P. Dec. 30, 1915, [Convention date]. Commutator s w i t c h i n g - arrangements.-Alternating currents are rectified, or direct currents are converted to alternating currents by means of mercury jets which traverse a magnetic field perpendicular to the jets and strike an electrode at a distance from the field dependent on the velocity of the mercury and the frequency of the alternating current. In Fig. 3, a jet is shown passing through a magnetic field F and striking a double electrode formed of two conducting-plates u, v separated by an insulating-wedge x. The un. bent jet is directed against the edge of the wedge, and, during successive half-waves of current, it makes contact with the plates u, v alternately. Accumulators p, Fig. 8, are connected in circuit with two jets s impinging on single electrodes, and are charged by the rectified current. The current through each jet flows through half a winding of the transformer used. The two electrodes may be combined together, and the transformer winding may be placed in that part of the circuit common to the two jets, while the batteries are connected in the divided circuits. The field in all these instances is alternating, and a coil may be included in the direct-current circuit to smooth the current pulses. For rectifying polyphase currents, a jet s, Fig. 22, is connected in series with the coils of the transformers, and the electrodes 71 are connected to the work circuit. Each jet is arranged to be in contact with its electrode plate 71 during onethird of the period of the supply. The second plate 70 of each electrode is connected across the jet and a part of the phase winding, and this auxiliary circuit may include a regulating-resist. auce. In this case, the current in the jet is alternating, and the magnetic field across the jet is constant. Each electrode may be doubled, so as to use both half-periods of the current, and the electrodes for all the phases may be combined together as shown in Fig. 24. In a modification, the jet s, Fig. 28, is influenced by the rotating field of the generator and moves over an electrode consisting of three sectors separated by the wedgeshaped insulators x. Two jets and two electrodes may be used with the direct-current load in the common part of the circuits. The jets may be obtained through glass tubes, or holes in a plate of iron, copper, &c. Each jet may be replaced by a series of jets, and the plate may form a sliding wall of the jet chamber, so that it may be readily removed for inspection, and so that the number of holes employed can be varied by displacing the slide over a fixed grating 81, Fig. 36. The insulating-plate x of each electrode with its conductors 18 19, Fig. 37, is supported on a base 15 and held by screws 20, 21. The base has a mercury groove 23 and is adjustable by screws in the direction of the jet. To prevent the jet from short-circuiting across the electrode plates, additional insulating-plates are introduced and separated by conducting-lamellµ connected to the electrode plates by resistances 98, 99, as shown in Fig. 42. The chamber containing the apparatus is filled with illuminating-gas or hydrogen and is provided with a safety-valve and an inspection window.