US2586404A - Starting and operating devices and circuits for electric discharge devices - Google Patents

Description

Feb. 19, 1952 P. WAGUET STARTING AND OPERATING CIRCUITS AND DEVICES FOR ELECTRIC DISCHARGE DEVICES Flled June 16, 1948 lnven'i'or'z phluppe Waguec, 103 M0 A MMM His A'btorneg Patented Feb. 19, 1952 STARTING AND OPERATING DEVICES AND CIRCUITS FOR ELECTRIC DISCHARGE DE- VICES- Philippe Waguet, Paris, France, assignor to Gen eral Electric Company, a corporation of New York- P Application June .16, 1948, Serial No. 33,386

In France June 14, 1947 2 Claims. (01. 315-165) This invention relates to electric discharge devices of the type employing ionizable mediums such as gases or vapors, and more particularly to starting and operating devices and circuits therefor.

An object of my invention is to provide a new and improved starting and operating circuit for electric discharge devices energized from a direct current source.

Another object of my invention is to provide an improved and simplified operating circuit for luminous electric discharge devices or fluorescent lamps energized in series from a direct current source, and utilizing an auxiliary dependent alternating voltage source for heating the electrodes and starting the discharge in the lamps.

My invention is of general applicability wherever it is desired to operate fluorescent lamps from a direct current supply. It has been found particularly useful in the illumination of cars on electrified railways and permits the immediate utilization of the direct current supplied to the locomotive, for instance the traction supply at 750 or 1500 volts, on the lighting circuits.

A feature of my invention is the utilization of an auxiliary direct-to-alternating current converter for heating the filamentary electrodes in the lamp and also for starting the discharge. This is achieved by means of a time-delay relay which permits the utilization of the induced voltage, resulting from the rupture of the field winding circuit of the converter, as astarting impulse for. the lamps.

For a more complete discussion of various circuits which may be utilized in operating fluorescent lamps from a direct current supply, refer ence is made to mycopending U. S. application No. 28,223, filed May 20, 1948. Other applications and improvements in such circuits are disclosed in my copending U. S. applications Nos. 28,224, 28,225 and 28,226, filed May 20, 1948, and 33,385 and 33,387, filed June 16, 1948. All of the above applications are assigned to the same as signee as the present application.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims. The drawing is a diagrammatic view of a plurality of electric discharge devices connected in series and a starting and operating device and circuit therefor incorporating my invention.

Referring to the drawing, I have there illustrated one embodiment of my invention as applied to a group of two or more serially connected electric discharge devices wherein the reference numerals for device la and the elements associated with device la are extended by indices to the other'serially connected device or devices. The electric discharge device la (and lb), such as a fluorescent lamp, therein illustrated comprises an elongated tubular or cylindrical envelope 2a having sealed into the ends thereof thermionic filamentary electrodes3a and 4a. Filamentary electrodes 3a and 4a may comprise a coil, preferably in the form of a coiled coil of tungsten wire activated with oxides of alkaline earth metals such as a mixture of barium and strontium oxides. The envelope 2a contains a gaseous atmosphere such as a rare gas like neon,

argon or mixtures thereof at a pressure of a few millimeters and a small quantity of mercury which, during the operation of the lamp, has a low pressure of the order of 10 microns. The device la may be a low pressure positive column lamp of a fluorescent type provided with a suitable phosphor or fluorescent coating. This fluorescent coating, upon excitation by the radiation produced by an electric discharge between the electrodes, transforms a shorter wave radiation due to the discharge into longer wave radiation such as radiation within the visible range. A pair of metal cups 5a and 6a serve to intercept the-particles of emissive material sputtered from electrodes 3a and 4a, respectively. These cups are usually tied by means of connections, either outside or inside of the lamp, to the extremities of electrodes 3a and 4a. A number of advantages result from the connections between filamentary electrodes 3a and 4a and the corresponding cups 5a and 6a, namely, utilization of cup 8a as an anode and eliminating the disintegration by ionic bombardment of filamentary electrode 4a, utilization of lamps that are usually employed with alternating current, reduction of operating voltage, doubling the life of thelamp by using Successively the two filamentary electrodes, i. e., by turning the lamps around when one of the filaments becomes inoperative.

Serially connected devices la and lb are connected across a suitable direct current power supply 1,1 which, for example, may be a traction voltage of either 750 or 1500 volts, and in series with an auxiliary or second direct current source of supply 8 which, for example, may be a storage battery having a potential of 72 volts and connected in series with the devices la and lb in such a manner that it will be charged by the current passing through the devices. The direct current source of supply 1, l supplies current to devices la andlb through stabilizing resistances 9a and 9b. Resistances 9a and 9b, for example, may be iron or tungsten wire enclosed in hydrogen. A starting and operating circuit l0, I is connected across the auxiliary direct current supply 8 and comprises, in series relationship a field winding section II of a dynamoelectric machine or rotary converter l2, a manual makeand-break switch l3, and a switching means it:

comprises a coil l9 connected across theterminals of the direct current sourcebf supply 1, 1'; Switching means l4, in addition, comprises a normally closed contactor 20 and a normally open contactor 2i in series with each other and with an. armature winding 22 ,of; dynamoelectric nachine l2 and switch l3,across ,the;auxiliary source of direct current Supply 8,, A time delay relay or switching means 23 comprising a contactorflin series with the direct. currentsource of supply I, l, and a coil 25 connected acrpsstheauxiliary source of directcinirentisllpply 8, energizes the starting and operating circuits for devices la and lb upon closure of switch L3,.

Transformers 25a and 25bcomprising primary winding sections Z'laiand. 27b and center-tapped secondary winding sections 28aand 2%, respectively, are connected in parallel across an alternating current supply 29,, 29' produced by the dynamoelectric machine ii. The secondary winding sections 28a and 28b serve to heat filamentary electrodes 4a andAb and to continue to heat these electrodes as long. asprimary winding sections 27a and 21b are energized. 'Ihe'center-tap of the secondary winding section 28b is connected through the ballasting resistance 9a to the filamentary electrode 3a of device la, and the centertap of the secondary winding section 28a. is connected through the auxiliary source of direct current supply 8 to the negative terminal I .of the direct current supply.

The operation of the circuit. and device illus trated in the drawing is as follows: In the rest position, as shown in the drawing, the contactors l6 and 2i are open and the contactors l andlll are closed. As soon as the starting switch I3 is closed, coil 25 .of the feeder relay 23 is energized, the contactor 24 closes and applies the network voltage to coil IQ of relay or switching means M,

as well as to all the lamps that are connected in series. Contactor l6 closes and applies voltage to field winding section ll; then contactor 2l closes, with a time delay of a few tenths of a second with respect to the closing of contactor l6, and applies voltage to the armature winding section 22 of the converter or dynamoelectricmachine l2, which now starts to operate. The cathode filamentary electrodes 4a and 4b are heated and after a few seconds the contactor 20 opens, interrupts the circuit of armature winding section 22 and stops the heating of the cathode filamen tary electrodes. A few tenthsof a second after the opening of contactor 20, contactor It opens and breaks the circuit of field winding section I I, thus setting up at point l8 a voltage impulse which is imparted to the auxiliary electrodes lid and I'll). As a result of this impulse the dis.- charge lamps la and lb. light up. In case the system voltage should fail, relay orswitching means M will immediately assume the r es t pos i tion, the contactors l5 and 20 close, contactors l6 and 2l open, and the armature and field circuits of the converter or dynamoelectric machine are interrupted. Upon re-establishment of the normal system voltage, the switching means l4 ain operates asjust described, so that the lamps are re-ignited in their entirety. Switching means l4 is so adjusted that it will not drop to the rest position unless the system voltage falls to a value slightly above the voltage at which the series connected lamps will go out. Should the system voltage fall below that value, switching means l4 drops. tow the rest position, just as in the case of no voltage.

It is evident that the circuit, which has been justv described for the case of a group of lamps that areconnected in series, is also applicable to any number of these series groups which are connected in parallel.

The retarded operation of contactors l 5, i6, 20, and 2l of switching means l4 may be brought about, for instance, by means of a mechanism set in motion by the coil 19 which causes the tilting of two glass bulbs containing mercury, the flow of which, suitably delayed by a capillary tube. serves to make or breakthe contact.

Other means for carryingoutthis function, such as mechanical timing. devices for instance, will occur to those skilled in the art. The appended claims are, therefore, intended to-cover anysuch modifications coming within the true spirit and scope of the invention.- 4

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. Apparatus for operatinga plurality of gaseous luminous electric discharge devices, of the type including a main thermionic electrode and a cooperating electrode, comprising: said devices, a unidirectional voltage source, and a ballast resistance; a rotary converter having a direct current field winding, a direct current input winding and an alternating current output winding; a transformer having a primary winding connected to said output winding and a plurality of secondary windings connected to said thermionic electrodes; a main discharge circuit constituted by connecting said devices in series, the thermionic electrode of one being connected to the cooperating electrode oianother in sequence, the two remaining main electrodes being connected, in series with said ballast resistance, across said source; a time delay relay having two sets of contacts respectively connectingsaid field and 'said input-windings across said source, said relay operating to energize in sequence, first said'field winding and then said input winding, and said relay then operating to de-energize in sequence after a predetermined time interval, first said input winding and then said field winding; and auxiliary starting electrodeson said devices .connected in common to the junction of said-field winding with the associated contact of said relay.

2. Apparatus for operating aplurality of fgasew ous luminous electric discharge devices,of the type including a main filamentary thermionic electrode and a cooperating main electrode, and an auxiliary startingelectrode located intermediate the ends thereof, comprising; said devices, a unidirectional voltage source, and a ballast resist ance; rotary converter' having a direct current field winding, a directcurrent input circuitand an alternating current output circuit; a transformer having a primary winding connectedto said output circuit and a plurality of secondary i -d ne n sctedto said fi mentar electrodes;

3 a main discharge circuit constituted by connecting said devices in series, the filamentary electrode of one being connected to the cooperating electrode of another in sequence, the two remaining main electrodes being connected, in series with said ballast resistance, across said source; and a time delay relay having two sets of contacts respectively connecting said field winding and said input circuit across said source, said relay operating to energize in sequence, first said field winding and then said input circuit, and said relay then operating to de-energize after a predetermined time interval sufficient to permit heating of said filamentary electrodes, first said input circuit and then said field winding; and direct connection between said auxiliary starting electrodes and the junction of said field winding with the associated contact of said relay.

6 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number PHILIPPE WAGUET.

Name Date Von Wedel July 14, 1931 Wiegand Feb. 9, 1932 Erickson Oct. 16, 1934 Lederer Nov. 12, 1935 McKesson Mar. 25, 1941 Lord Aug. 19, 1941 Campbell Dec. 21, 1948 Mills Feb. 22, 1949 FOREIGN PATENTS Country Date France Oct. 22, 1940

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