US2020707A - Gaseous electric discharge lamp device - Google Patents

Description

Nov--32, 93 W. UYTERHOEVEN ET AL 2,020,707

GASEOUS ELECTRIC DISCHARGE LAMP DEVICE Filed Sept. 4, 1934 INVENTCRS 96%),

BY da ATT Patented Nov. 12, 1935 UNITED STATES 2,020,701 GASEOUS amc'rmc mscmmca LAMP DEVICE Willem Uyterhoeven and Aart de Bruin, Eindlioven, Netherlands, assignors to General Electric Company, a corporation of New York Application September 4, 1934, Serial No. 742,685

Germany September 13, 1933 4 Claims. (Cl. 176-124) The present invention relates generally to gaseous electric discharge lamp devices and more particularly the invention relates to starting and operating circuits for a plurality of such devices 6 similar to that described in co-pending application, Serial Number 645,283, filed December 1, 1932, the inventor being Hendrik A. W. Klinkhamer.

In the co-pending application an illuminating 10 system is disclosed which comprises a plurality of gas filled electric discharge devices, each having a thermionic electrode, and a plurality of transformers, one for each of said devices, having the primaries thereof connected in series to the terminals of a .current source. The operating voltage of such devices is appreciably lower than the starting potential thereof. The voltage of the current source in such a system must be greater than the sum of the operating voltages of the various devices but need not equal the" sum of the starting potentialsof the devices. As a result of the cooperative action of the thermionic electrodes and of the series-wired transformers, the potential necessary to start the lamp devices in the system is smaller than the sum of the starting potentials of the devices. When external impedanceconsisting of ohmic resistances are used, this has the advantage that these resistances can be made smaller so that the energy which is lost therein is reduced. If, as is customary, the external impedance consists of an auto-induction then this also can be made smaller which results in a better performance factor.

The object of the invention is to improve the 85 efliciency and the powfi' factor of illuminating systems of this type. Still further objects and advantages attaching to. the device and to its use and operation will be apparent to those skilled in the art from the following particular de- 40 scription.

The illuminating system according to the present invention comprises a plurality of three-phase gaseous electric discharge devices, the containers of which consist of three legs having a common end and having a thermionic electrode sealed into the end thereof opposite said common end. The electrodes of each tube are connected to three secondary transformer windings, one for each electrode, while the respective primaries of the 60 transformers are connected in series to a three phase current source.

When current is applied to the system an unequal distribution of the total potential occurs. over the different transformers. The devices 65 connected to the transformers which receive the higher potential start first whereupon the voltage distribution changes and other devices receive the higher voltage necessary for starting. Now this effect is supported by the fact that the voltage can distribute itself unequally not-only over the different transformers but also over the coils of each transformer. Aside from this there is a constant displacement of the potential at the tiein point of the devices (that is the point where the legs of the devices pass over into one an- In other). With a symmetrical distribution of the potential in the legs of the devices, the tie-in point (aside from voltage losses) is at the same potential with regard to each of said electrodes. But, if a. current begins to flow between two 15 thermionic electrodes, then the discharge path between these electrodes can be looked upon as an ohmic resistancev and the tie-in point assumes the potential of the middle of this discharge path and thus assumes a higher potential in relation 20 to the third electrode, whereby starting of the tubes is facilitated.

This can .be best seen if one visualizes the potential existing in the tube as vectors (see Fig. 1 of the drawing accompanying and forming part 25 of this specification). With a symmetrical voltage distribution, the potentials between the tie-in point and the electrodes are represented as vectors I, 2 and 3. Now if a current begins to flow between the hot electrodes which are connected 30 with the potentials I and 3, then the tie-in point assumes the potential of the point 5, so that its potential in relation to the third electrode is not represented any more by the distance 4-6 but by the distance 5-8.

By means of the cooperative action of the above mentioned phenomena ignition of the devices is. facilitated very much so that the total voltage in relation to the sum of the individual starting voltages can be chosen lower, which, as has been mentioned already, brings with it a reduction of the external impedances and therefore a reduction of the losses or an improvement in the performance factor.

Fig. 2 of the drawing is a schematic represen- 45 tation of an illuminating system embodying the invention.

The system comprises a number of three phase transformers the primary coils l of which are connected in series to the conductors of a three phase alternating current circuit. The alternating current circuit is fed from a three phase alternating current source 2. The secondary windings3 are in a star circuit (triangular circuit is also possible) while the free ends of these windings are connected over the external impedances 4 with the thermionic electrodes 5 of the discharge lamp devices. It is also possible to use leaky transformers, in which case the external impedances 4 can be omitted. The external impedances can also be placed in the main circuits, while mutual impedances can be used for all the devices. Each device has three legs 6 which pass over into each other at one end and contain the thermionic electrodes 5 at the other end. It will be understood, that, aside from the thermionic electrodes 5, special anodes can also be mounted in the tubes. The legs are so arranged that their axes form the edges of a triangular prism, while the distance between the walls of the legs is made small. The devices contain a gas, for example, neon under low pressure, approximately 1 to 10 mm., and a vapor which participates in the light emission, for instance sodium vapor. The electrodes are directly or indirectly heated thermionic electrodes, comprising a heater element, such as a filament, in operative relation to an electron emitting material, such as a barium oxide coating, and are heated by a special heater current, or by the discharge, when desired.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:-

1. An illuminating system comprising in combination a plurality of gaseous electric discharge lamp devices and a plurality of transformers therefor, each of said devices comprising a container having three tubes having a common end and a thermionic electrode sealed into the end of each tube opposite said common end, a gaseous filling in said container, each of said electrodes being connected to the secondary of one of said transformers, the secondaries for the electrodes of one of said devices being connected to each other in star, the primaries of said transformers being connected in series to the terminals of a three phase alternating current source.

2. 'An illuminating system comprising in combination a plurality of gaseous electric discharge lamp devices and a plurality of transformers therefor, each of said devices comprising a container having three tubes having a common end and a thermionic electrode sealed into the end of each tube opposite said common end, a gaseous filling comprising sodium vapor in said container, each of said electrodes being connected to the secondary of one of said transformers, the secondaries for the electrodes of one of said devices being connected to each other in star, the primaries of said transformers being connected in series to the terminals of a three phase alternating current source.

3. An illuminating system comprising in combination a plurality of gaseous electric discharge lamp devices and a plurality of transformers therefor, each of said devices comprising a container having three tubes having a common end and a thermionic electrode sealed into the end of each tube opposite said common end, a gaseous filling comprising a rare gas and sodium vapor in said container, each of said electrodes being connected to the secondary of one of said transformers, the secondaries for the electrodes of one of said devices being connected to each other in star, the primaries of said transformers being connected in series to the terminals of a three phase alternating current source.

4. An illuminating system comprising in combination a plurality of gaseous electric discharge lamp devices and a plurality of transformers therefor, each of said devices comprising a container having three tubes having a common end 35 and a thermionic electrode sealed into the end of each tube opposite said common end, a gaseous filling comprising neon and sodium vapor in said container, each of said electrodes being connected to the secondary of one of said transformers, the secondaries for the electrodes of one of said devices being connected to each other in star, the primaries of said transformers being connected in series to the terminals of a three phase 45 alternating current source.

WILLEM UYTERHOEVEN. AART DE BRUIN.

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