US2589754A - Starting and operating device and circuits for electric discharge devices - Google Patents

Description

P. WAGUET March 18, 1952 STARTING AND OPERATING DEVICE AND CIRCUITS 2 SHEETSFSHEET 1 FOR ELECTRIC DISCHARGE DEVICES Filed May 20, 1948 ITWVi'TWTQTI PhlLlppe Wage lr, y W W His A b t'ovn eg March 18, 1952 P. WAGUET 2,589,754

STARTING AND OPERATING DEVICE AND CIRCUITS FOR ELECTRIC DISCHARGE DEVICES Filed May 20, 1948 2 SHEETS-SHEET 2 F gs.

lnvewtov: PhiLippe Wa guet b5 Z/WC IY His Attor-ne9 Patented Mar. 18, 1952 2,589,754 AR ND, ATING. E ICE AND CIRCUITS FOR ELECTRIC DISCHARGE DEVICES Philippe Waguet, Paris, France, assignor to General Electric Company, a corporation of New York Application May 20, 1948, Serial No. 28,223 In France June 14, 1947 2 Claims. 1

This invention relates to electric discharge devices of the type employing ionizable mediums such as gases or vapors and more particularly to direct-current energized starting and operating devices and circuits therefor.

An object of my invention is to provide new and improved starting and operating circuits for electric discharge lamps energized from direct current sources.

Another object of my invention is to provide new and improved starting and operating circuits for electric discharge devices energized from a direct current source, which will preheat filamentary electrodes and subsequently impress, upon auxiliary starting electrodes, a single voltage impulse for initiating discharges between main electrodes in the devices.

My invention is of general applicability wherever direct current sources are utilized, and is particularly useful in the lighting of vehicles and railroad cars. Further applications and improvements in connection with such uses are described in my copending U. S. applications Nos. 28,244, 28,255, and 28,226, filed May 20, 1948, and Nos. 33,385, 33,386, and 33,387, filed June 16, 1948, all assigned to the same assignee as the present invention. These applications have matured into U. S. Patents Nos. 2,586,400, 2,586,401, 2,586,402, 2,586,403, 2,586,404 and 2,586,405, all issued. Feb. 19, 1952.

Further features and advantages of my invention will appear from the following. detailed de-' scription of species thereof.

For a better understanding of my invention reference may be had to the following description I taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims. Fig. 1 is a diagrammatic view of an electric discharge device and a starting and operating circuit therefor incorporating my invention; Fig. 2-7 illustrate variations of the circuit shown in Fig. 1; Fig. 8 illustrates diagrammatically an electric discharge device and a filamentary preheating circuit and a starting circuit incorporating my invention; Fig. 9 illustrates a variation of the circuit shown in Fig. 8 and is adaptable for starting any number of electric discharge devices that are connected in parallel.

In accordance with my invention, I have provided a means of. imparting temporarily to an auxiliary electrode in the vicinity of an electric discharge lamp a starting potential exceeding that of the anode or less than that of a filamentary electrode serving as a cathode. I ac'corm push this b breaking an inductive" starting'cir- Lil.

2 cult one or more seconds after the application of a heating potential to the filamentary electrode. My invention is particularly characterized by the connection which is established between the auxiliary electrode and a point which is located between the break and the inductance.

The starting circuit is connected either in series with the cathode filament or in parallel with the lamp circuit. In the first case, this starting circuit serves also (prior to its breaking) to effectuate the heating of the cathode filament; in the second case, the cathode filament is connected in series with an auxiliary circuit, the current flow through that circuit insuring the heating of the cathode filament.

The starting circuit, when connected in parallel with the lamp circuit, may serve to ignite any number of lamps that are connected in parallel.

The heating current is always suppressed once the ignition attempt has been made.

The control of the starting circuit and possibly of the auxiliary heating circuit may be mariual or automatic. In the case of amanual opera tion, a contactor is used which is kept closed for one or several seconds so as to insure proper heating of the cathode filament. In the case of automatic control, a relay is used whose coil is connected in parallel with the lamp circuit, said relay opening the starting circuit and, if necessary, the heating circuit, one or more seconds after the application of the voltage to the terminals of that coil.

Referring to Fig. 1, I have there illustrated one embodiment of my invention as applied to an electric discharge device I. The electric discharge device I, such as a fluorescent lamp, therein illustrated comprises an elongated tubular or cylindrical envelope 2 having sealed into the ends thereof thermionic filamentary electrodes 3 and 4. Filamentary electrodes 3 and 4 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 2 may contain a gaseous atmosphere such as a rare gas, likeneon, argon, or mixtures thereof, at a pressure of a few millimeters and a small quantity of mercury which, during the operation of the lamp, may have a low pressure of the order of 10 microns. The device I 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 dischargebetween 3 the electrodes, transforms a shorter wave radiation such as radiation due to the discharge into longer wave radiation such as radiation within the visible range. A pair of metal cups and 6 serve to intercept emissive material sputtered from electrodes 3 and 4, respectively. These cups are usually tied by means of connections, either outside or inside of the lamp, to the extremity of electrodes 3 and 4. A number of advantages result from the connections between filamentary electrodes 3 and 4 and the corresponding cups 5 and 6, namely, utilization of cup 6 as an anode and eliminating the disintegration by ionic bombardment of filamentary electrode 4, utilization of lamps that are usually employed with alternating current, reduction of operating voltage, doubling the life of lamps by using successively the two filamentary electrodes, 1. e., by turning the lamp around when one of the filaments becomes inoperative.

Device I is connected across a suitable direct current power supply circuit I, I' for supplying current to device I through a stabilizing resistance 8. Resistance 8, for example, may be an iron or tungsten wire enclosed in hydrogen. A manual make-and-break control switch 9 may be used to connect device I to the power supply. A starting and operating circuit III, III is connected through filamentary electrode 3 across the current supply I, I and comprises an inductance I I,

a manual contactor or switch I2, and a resistance I3. An auxiliary electrode I4, mounted adjacent device I, is connected to a point I5 intermediate inductance I I and switch I2. Resistance I3 serves to regulate the density of the preheating current and at the same time the value of the potential which the auxiliary electrode I4 assumes temporarily.

When the entire installation is energized, the operation of device I and circuit therefor is as follows: With the manually operated main switch 9 closed, the current is established in the parallel starting circuit ID, ID whenever the contactor or switch I2 is closed.- Filamentary electrode 3 is heated and inductance I I is magnetized; the opening of contactor or switch I2 a few moments after its closing, brings the voltage of the auxiliary electrode I4 to a transient value which is either above that of the positive side of the direct current source I, I (as indicated in Fig. 1) or below that of the negative side of the direct current source I, 'I (asin the case of Fig. 2 in which the physical location of the inductance I I and resistance I3 are reversed). a

The transient voltage between the metal cup 6 serving as an anode and the auxiliary electrode I4 (as in the case of Fig. 1) or between the filamentary electrode 3 serving as a cathode and the auxiliary electrode I4 (as in the case of Fig. 2) is proportional to the current that flows through the inductance I I during the closing of contactor or switch I2, and thus inversely proportional to the value of resistance I3. For agiven value of that current it is recommended to utilize an inductance whose resistance is as low as'possible.

In Fig. 3, in which the elements that correspond to those of Figs. 1 and 2 are identically marked, I have represented a variant in which the inductance I I is connected to a point I6 be-v tween device I and ballast'resistor 8 instead of being connected to the positive side of the direct current source I, I as in Fig. 1. This particular circuit arrangement is less effective than the preceding circuits in Figs. 1 and 2 for it permits only a lower voltage- betweenelectrodes 3 and 4 at the start; moreover, if the heating current exceeds the normal discharge current (and this is generally the case), the stabilizing resistance 8 becomes temporarily overloaded.

In Fig. 4, in whichthe elements that correspond to those of Fig. 1 are correspondingly marked, the inductance II is placed in the discharge circuit between the positive terminal of the supply I, I and the stabilizing resistance 8; point I5 is connected to a point I1 which resistance 8 and inductance I I have in common. Moreover, the opening of contactor or switch I2 sets up, besides the overvoltage at the auxiliary electrode, an overvoltage of the same magnitude at the anode or electrode 4. v

In Fig. 5, I have represented a variant of Fig.

'4 in which point I5 is no longer connected to the point which resistance 8 and inductance II have in common, but is connected to point I8 between device I and resistance 8. Compared to the hookup of Fig. 4, this circuit has the disadvantage that the overvoltage at the auxiliary electrode I4 and at the anode or electrode 4 is lessened by a certain amount, i. e., by the voltage drop in the stabilizing resistance 8. Besides, this resistance 8 is overloaded as long as the lamp is not conducting.

In Fig. 6, which is a variant of Fig. 4, the inductance I I is subdivided into two parts: one part I la, is placed (as in Fig. 5) in the discharge circuit, the other part I Ib, is placed in the starting circuit. Besides causing an overvoltage at the auxiliary electrode, this inductance sets up an overvoltage at the anode.

In Fig. 7, in which the elements that correspond to those of Fig. 1 have the same notation, except that manual make-and-break switch 9,

when closed, energizes a relay coil which interrupts the starting circuit II], II), I have represented an automatic control of the starting circuit III, I0 when that circuit is connected in series with the cathode filamentary electrode 3. This control is brought about by a time-delay relay I9, at 001120 of which is connected in parallel with the lamp circuit at a point 2I located between switch 9 and the terminal I" of the direct current supply circuit.

The operation of the circuit illustrated in Fig. '7 is as follows: In the rest position, contact I2 is closed. As soon as switch 9 is closed the oathode filamentary electrode 3 is heated, inductance II is magnetized, and coil 20 of the relay is energized. After one or several seconds the relay begins to operate and opens contact I2,thus igniting the electric discharge lamp.

In Fig. 8, in which the elements that correspond to those of Fig. 1 are correspondingly numbered, the starting circuit is branched off the lamp circuit at a point 2I located between switch 9 and terminal I of the direct current supply. An end 22 of the cathode filamentary electrode 3 is connected to terminal 'I' of the direct current supply by means of a limiting resistance 23 and a contact 24, the contacts I2 and 24 being the two coupled elements of a double-pole contactor 25. The operation of the circuit illustrated in Fig. 8 is as follows: Switch 9 having been first closed, as soon as contacts I2 and 24 of the double-pole switch 25 are closed, the cathode filamentary electrode 3 is heated and inductance II is magnetized. The opening of this switch 25 one or several seconds after its closing, lights up the lamp and discontinues the application of the heating current. f

In Fig. 9, in which the elements that correspond to those of Fig. 8 have the same notation, except that now the notation is extended by the use of indices to any number of lamps, and that element 9, when closed, energizes a relay coil which interrupts the starting circuit [0, I, I have represented an automatic control of the starting circuit and of an auxiliary heating circuit. This control is made possible by a timedelay relay 26, comprising a pair of contacts I2 and 21 and a coil 28 which is branched off the lamp circuit or discharge circuit between points 2|, 29 and the terminal 1' of the direct current source of supply. Contact I2 is located in the starting circuit I0, I0 and contact 2'! in the auxiliary heating circuit, the latter contact 21 being between the terminal I of the direct current supply and the wire which the limiting resistances 23, 23 have in common. The auxiliary electrodes l4, 14' are connected to a point 30 located between inductances H and contact l2 by means of a wire which all have in common.

The operation is as follows: With contacts l2 and 2'! closed in the rest position, as soon as switch 9 is closed the cathode filamentary electrodes 3, 3' are heated, inductance l is magnetized and the coil 28 of the relay 25 is energized. After one or several seconds the relay operates, opens the contacts l2 and 21 which ignites the lamps and discontlnues the application of the heating current to the cathode filamentary electrodes.

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

1. Apparatus for o erating a a eous electric discharge device of the type including a main thermionic electrode and a cooperating main electrode from a unidirectional voltage source comprising: a discharge circuit including said device, a control switch anda ballast resistance connected in series across said source; a first auxiliary circuit for preheating said device comprising said control switch, said thermionic electrode, a limiting resistance and a normally closed contact of a time-delay relay serially connected across said source; a second auxiliary circuit for starting said device comprising said control switch, a limiting resistance, a second normally closed contact of said relay, and an inductance serially connected across said source; an auxiliary starting electrode for said device positioned intermediate the ends thereof; a direct comiection between said starting electrode and the inductive side of said second contact; and a circuit through said control switch and the operating coil of said relay for opening said contacts at a predetermined time interval after the closing of said control switch.

2. Apparatus for operating a plurality of gaseous electric discharge devices, of the type comprising a main filamentary electrode and a cooperating main electrode, comprising: a source of unidirectional voltage, a common control switch, a plurality of ballast resistances, a plurality of discharge circuits including said devices connected in parallel across said source through said common control switch, each of said devices being connected in series with one of said ballast resistance; a first auxiliary circuit for preheating said devices comprising said control switch, said filamentary electrodes in parallel, and a normally closed contact of a timedelay relay serially connected across said source; a second auxiliary circuit for starting said devices comprising said control switch, a limiting resistance, a second normally clo ed contact of said relay, and an inductance serially and sequentially connected across said source; auxiliary electrodes serving as starting means for said devices and positioned intermediate the ends thereof; direct connections between said starting electrodes and the inductive side of said second contact; and a circuit through said control switch and the operating coil of said relay for opening said contacts at a predetermined time interval after the closing of said control switch.

PHILIPPE WAGUET.

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

UNITED STATES PATENTS Number Name Date 2,020,731 Lederer Nov. 12, 1935 2,456,859 Campbell Dec. 21, 1948 FOREIGN PATENTS Number Country Date 861,198 France Oct. 22, 1940

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