Патент USA US2126291код для вставки
Aug. 9, 1938. ‘ ‘ 7 J, SLEPIAN 2,126,291 VAPOR ELECTRIC CONVERTER “ Filed March 24, 1937 . + WITNESSES : V Y .Zoseph S/ep/bn. @53 - ' _ B a ‘ ‘ 1 ATORNEY \ Patented Aug. 9, 1938 2,125,291‘ warren srnrss ‘PATENT. creme 2,126,291 , . VAPOR ELECTRIC CONVERTER Joseph Slepian, Pittsburgh, Pa, assignor to West inghouse Electric & Manufacturing Company, East Pittsburgh, Pa, a corporation of Penn ‘ sylvania . Application March 24, 1937, Serial No. 132,830 8 Claims. (Cl. 1'75—363) My invention relates to a vapor electric‘ con verter and particularly to an ignition system for such a converter. Since this block of cathode material, the heater circuit is never In the operation of vapor electric converters having a make-alive type of excitation, it has been found that there is considerable delay inthe formation of the rectifying arc to the anode. This delay has been particularly noted in regard to the high resistance low current type of igniter, 10 sometimes being of the order of several thousand micro-seconds. By observation of the operation of these devices, I believe that this effect results because the startingcurrent arc does not produce su?icient vapor for the quick transfer of the arc 15 to the main electrodes. the material of the cathode. metal remains permanently in contact with the broken. Another method of preventing the heating cir ‘cuit from being interrupted by motion of the cathode material, .is to provide two terminals to the make-alive electrode for the flow of heating current, which are independent of‘ the cathode material. This may be done by making the make alive electrode of hair-lpin form. Other objects and advantages of my invention will be apparent. from the following detailed de scription taken in conjunction with the accom panying drawing, in which: ' Another trouble met with in converters of this type is that liquid mercury may condense or be thrown upon the igniter electrode and stick there. This condensed mercury causes a large increase 20 in the current required by the igniter for starting the arc. According to my invention, this delay in start~ ing may be eliminated and the sticking of mer cury to the igniter prevented by‘applying heat to the vicinity of the auxiliary or make-alive elec trode. This heat may be applied directly to the make-alive electrode‘ by passing a suitable heat-‘ > Fig- 1 is a schematic illustration of a converter embodying my invention; Fig. 2 is a similar view of a converter embocly— ing an independent heater; 7 Fig. 3 is a modi?cation similar to Fig. 1, but 20 having an independent sourceof excitation; Fig. 4 is a further modi?cation showing the use of an independent heater element; and Fig. 5 is a modi?cation showing a hairpin type of make-alive electrode. . 25 The construction according to my invention is a simple arc chamber I having a single anode 2 ing current therethrough, or may be applied in and a cathode 3 with a make-alive electrode 4 directly by an independent heating element adja supplied from the anode circuit 5 by a suitable uni-directional conductor, such as a glow tube 6. 30 In normal operation of my device, the glowtube cent to the electrode. In either event sufficient heat should be generated to keep the auxiliary electrode free of condensed mercury and to main tain a slight vapor pressure in the vicinity thereof. When the heating current is passed through‘ ' the auxiliary electrode, it has been noted that a current much smaller than the current which will regularly produce a cathode spot will occasionally cause a random occurrence of a cathode spot. I believe‘ that this random occurrence is caused by 40 the heating current producing sufficient vapor pressure to push the ‘cathode material away from contact with the auxiliary electrode and thus 5 will,’ break downupon the application of posi tive potential'to the anode 2 and passes starting current‘ to the make-alive electrode li, which initi ates a cathode spot, which in turn strikes the 35 main arc and short circuits the glow tube 6 re moving current from the make-alive electrode. To this simple converter I add a heating circuit by placing in shunt with the glow tube a resistance it which allows a continuous heating current to 40 ?ow through‘ the make—alive electrode. This re sistance iii should‘ be of such a value that the heating current is‘ well below the value of‘ cur create a spark which initiates the cathode spot. I have found that this random occurrence can be rent‘ necessary‘ to initiate a cathode spot. prevented by, suitably cooling the end of the make-‘alive electrode in contact with the cathode In order to prevent unnecessary heating of that portion‘ of the electrode 4 in contact with the. material or by having the end of the make-alive electrode in permanent electrical contact with a highly conducting element which is in permanent 50 electrical contact with the‘ cathode material. While this cooling may be done by immersing the cathode, I prefer to provide a cooling element by cathode material ' 3“, _I provide“ the make-alive electrode with a suitable cooling element in the form of a metallic block i l attached to the elec trode and immersed in the cathode material 3. In the modi?cation according to Fig. 2, the heating of the auxiliary electrode i is accom plished by means of a heating coil l5 supplied attaching a block of metal, such as iron, to the tip of the electrode and immersing the same into transformer l6. 45 ‘ make-alive electrode a suitable depth into the 55 , from a suitable source of current, such as a 55 2 2,126,291 In the modi?cation according to Fig. 3, the ex citation or ignition current for the converter is applied to the make-alive electrode 4 from a suitable source, such as a transformer 20, through a grid-controlled discharge device 2|, the grid of which is controlled bythe potential applied to the anode 2 of the converter. The auxiliary dis charge tube is by-passed by a suitable resistance IE! for providing heating current to the make alive electrode 4. In the modi?cation according to Fig. 4 the make-alive current is controlled by a commutat ing device 25 driven by a suitable motor 26 pref erably a synchronous motor. In order to prevent sparking at the commutator I provide a suitable capacitor 21 bridging the contacts. A resistor 28 of proper capacity may be placed in parallel with the capacitor 2'! to pass heating current through the electrode 4. By properly propor tioning resistors l0 and 28 the heating effect may be divided between the heater coil l5 and the heating. current passing through the electrode 4. While the return connection from the coil l5 to 25 the current source 29 may be made in any pre ferred way I prefer to connect the coil 15 directly to the cathode 3 and protect it from the arc by a suitable insulating sleeve 30 in order to reduce the number of vacuum seals required. In the modi?cation according to Fig. 5 a hair 30 pin type of make-alive electrode is utilized com prizing two make-alive elements connected to gether by means of the cooling block II’. A suitable heating current is circulated through the and means for cooling the portion of the make alive electrode immersed in the vaporizable cathode. 2. A vapor-electric converter comprising an arc chamber, a plurality of main electrodes in said chamber, one of said main electrodes being of vaporizable material, a make-alive electrode in contact with said vaporizable electrode, means for periodically passing make-alive current through said make-alive electrode, and means for continuously passing a lesser current through said make-alive electrode. 3. A vapor-electric converter comprising an arc chamber, a plurality of main electrodes in said chamber, one of said main electrodes being of vaporizable material, a make-alive electrode in contact with said vaporizable electrode, means for ‘periodically passing make-alive current through said make-alive electrode, means for continuously passing a lesser current through said make-alive electrode, and means for pre venting said lesser current from accidentally creating a cathode spot on said vaporizable electrode. 4.. An ignition system for a vapor-electric de 9.5 vice comprising an ignition electrode in contact with the cathode of the device, a source of poten tial for said electrode, a uni-directional conductor for passing igniting current to said electrode, and means for heating the ignition electrode. 3 (l 5. An ignition system for a vapor-electric de vice comprising an ignition electrode in contact with the cathode of the device, a source of poten tial for said electrode, a unidirectional conductor make~alive electrodes from any suitable source such as a heating transformer 35. The make for passing igniting current to said electrode, alive current from anode connection 5 is supplied by discharge device 6 preferably to a mid tap on the secondary winding of transformer 35. In the operation of these devices whether the current is supplied directly to the auxiliary elec trode or to an independent heating element l5 associated therewith, the heating current pro the vicinity of the ignition electrode. 6. A make-alive system for a vapor-electric converter comprising a make-alive electrode in duces a continual evaporation of the material ously supplying a heating current to said make alive. 7. An ignition system for a vapor-electric con verter having an arc-chamber and a plurality of main electrodes therein, comprising an auxil iary electrode having a portion thereof immersed in one of said main electrodes, a source of poten tial for said auxiliary electrode, means for inter adjacent to the auxiliary electrode, and conse quently maintains a vapor pressure in the vicinity of the auxiliary electrode 4. Also by maintaining the auxiliary electrode at a relatively high tem perature, it prevents condensation of the cathode material on the surface of the auxiliary electrode. While I have shown and described speci?c embodiments of my invention, it will be apparent to those skilled in the art that many modi?ca tions can be made therein without departing from the true spirit of my invention by the scope of the appended claims. I claim as my invention: 1. A vapor~electric converter comprising an arc-chamber, a pair of main electrodes therein, 60 at least one of said electrodes being of vaporizable material, a make-alive electrode having a portion thereof immersed in said vaporizable electrode, means responsive to the polarity of the potential impressed on the main electrodes for impressing make-alive current on said make-alive electrode, a resistance in shunt with said means for impress ing a lesser current on said make-alive electrode and means for maintaining a vapor pressure in contact with the cathode material of said con 40 verter, a source of potential for supplying cur rent to said make-alive, means for interrupting the make-alive current and means for continu mittently applying said potential to said auxiliary electrode and means for heating said auxiliary electrode. 8. An ignition system for a vapor-electric con verter having an arc-chamber and a plurality of main electrodes therein, comprising an auxiliary electrode having a portion thereof in contact with one of the main electrodes, a connection with the main electrode supply circuit for supplying cur rent to said auxiliary electrode, means in said circuit for interrupting the current to said auxil iary electrode and means for by-passing current around said interrupting means for heating the auxiliary electrode. JOSEPH SLEPIAN.