US2339307A - Starting and operating circuit for gaseous electric discharge devices - Google Patents

Description

Jan. 18, 1944. A. WARSHER ET AL 2,339,307

STARTING AND OPERATING CIRCUIT FOR GASEOUS ELECTRIC DISCHARGE DEVICES Filed Jan. 8, 1941.

32 J1 I a INVENTORS Ma nard A.fiabb Ad ph Wans/zer Patented Jan. 18, 1 944 2,339,301 AND OPERATING cmcorrroa ELEc'rmo mscnmon' ma:-

STARTING GASEOUS VICES Adolph"Warsher, Maywood, and Maynard A.

Babb, Tenafly, N. .L, assignors, signments, to Maxwell M. Bilofsky,

by meme as- Newark,

Application January 8, 1941, Serial No. 373,570

7 Claims. (01. 176-124) The present invention relates primaril y to gaseous electric discharge devices such as fluorescent lamps and more especially to means and methods for starting and operating the 'same.

Among the objects of the invention are to pro-' vide starting means for discharge. devices and more especially for lamps of the above type, which shall be economical both in initiallcost and in power consumption and which shall effect the necessary step up of voltage thereacrossfto start even large or long lamps and that, without resort to transformers or auto transformers tor the purpose, and which shall inherently operate with the desired high power factor and without the needior special compensating equipment for the purpose.

In the accompanying drawing in whlch are shown one or more of various possible embodiments of the several features of the invention,

Fig. 1'is a diagrammatic view of the circuit as used for a hot cathode lamp, and g Fig. 2 is a diagrammatic view similar to Fig.

, 1 showing the general application to a lamp of the cold cathode type. L

, Referring now tofthe drawing, there is shown in Fig. 1 a gaseous electric discharge device In which may be of entirely conventional construction. In the lamp embodiment shown, the device comprises a glass tube carrying at its opposite ends heater filaments ll, each with terminals l2 and I 3, each of said filaments being coateither by a separate coil- (not shown) in main l5, or, if desired, by flux irom the choke coil l6, substantially as in the prior Patent No. 2,155,- 816, of Maynard A. Babb, issued April 25', 1939. The switch 23 is'arranged torem'ain closed only during the short time necessary afterclosing the mainswit'ch 24, for bringing the filament current to'a magnitude suflicient to heat the filaments to the,required temperature, whereupon ed with electron emissive material, such as bar- .ium oxide. The tube is evacuated and charged with neon gas or the like, which in the fiuores: cent embodiment is admixed with a a small amount of mercury vapor.

Thelamp is shown in Fig. 1 connected across the alternating current mains l4 and I5, oneof ,which has an, inductive reactance ballast or choke coil l6 therein. Across or in parallel with the lamp there is a fixed electric condenser l1. Desirably the condenser i1 is connected by leads l8 and I! to terminals l2 of the respective filaments ll. t

Connecting the heater filaments H in series is a second electric condenser 20. To this end, condenser 20 is preferably connected by leads 2| and 22to terminals l3 of the respective heater filaments H. -In series with condenser 20 is a switch 23. This switch may be or any of numerous well known types. It may be manually operated, it may be a gaseous valve or a thermally operatedswitch of any of the various bi-metallic types, or an electromagnetic switch operated corresponding capacitance made with nated paper dielectric oras compared with that said switch is to open. -The condenser 20 thus remains in circuit ateach start forbut so short a time that an electrolytic condenser of 'tlietype commonly'used for splitting phase in starting of small alternating current motors is entirelyifeasible. 3 Its use effects considerable saving as compared to the cost of an impregof other types of condenser suitable for permanent rather than mere starting connection in alternating current circuits. Thus condenser 20 which remains in circuit only during starting would be of the inexpensive electrolytictype, and

only condenser l1 which is of relatively small.

would be of the more expensive type. while the'sy stem capacitance The switch 23 remains closed is out of operation. When t v thrown, the condenser 20 is incircuit; current passing through choke coil l6, lead l8,one heater filament ll, lead 2! and by way of condenser 20 and closed switch 23 and lead 22 through the other filament H to the opposite main. Atthe same'time, a potential isimposed acros's" the lamp terminals and the condenser l1. In a generic sense, both condensers bridge across the electrodes of the lamp prior to arcing, the condenser bridging across the arc oi the lamp, while condenser 2 intervenesbetween and is in series with the filaments. Condenser I! thus increases the effective voltage available across the f terminals of the lamp. The condenser 21115 of such capacitance, that in the circuit set forth, the filament current will rapidly build upv to the required value. When the filament current has reached a value to produce the desired heatin otthe filaments, switch-211s opened-with removal of the electrolytic condenser n iirom the circuit. The voltage built up across the lamp ter- .minalsby condenser ll in conjunction with the kick =from-the chokegcoil lfigivesthe high voltage starting impulse acrossthenow heated filaments ll .to cause lamp Hi to are over or fire. I

It will be understood that thecapacitative-re-, actance oi the condenser l1 'havingin parallel electrostatic condenser ofv main switch 24 is objectives above indicated.

'ifords a step up of voltage across the lamp to therewith the combination of condenser 20 and filaments I I is designed so that the impedance of the entire circuit limits the current to the proper filament heating current. As a consequence the voltage across the lamp builds up to high values to assure arcing over in starting. After the are hasstruck, the operation procceds on high power factor, since the ohmicresistance of the lamp with the condenser H in parallel therewith, corrects the low power factor resulting from the inductive ballast electric discharge. V 7

While the invention lends itself to use with a wide variety of gaseous electric discharge devices of all sizes,'and especially to lamps (including those used for illumination and those for'advertising, such as neon lamps) it has particular utility where these lamps are of considerable length and wattage such as lamps of 30 watts or more, In one illustrative embodiment of many that are possible, a 40 watt lamp. four feet .long operated from a 60 cycle alternating current line of 110 volts, could have a choke of, 0.4 henrys, an electrostatic. condenser across the lamp or 1.25 microfarads and an electrolytic condenser between the filaments of 4.4 microfarads, and the heater filaments might pass .8. ampere when the-arc is about to strike. 'I'he operating current of the lamp would be about .4 ampere.

The initial cost of equipment for the circuit is seen to berelatively low, since the highcapacitance used only in completing the starting circuit through the heater filaments may be and is of the relatively inexpensive electrolytic type. The permanent capacitance used to maintain the v voltage across the lamp is of relatively small capacity and itscost therefore is moderate even it for the circuit by opening of switch 32.

builds up-to such tremendous values, as to cause the arc to strike across the cold cathodes. After the arc has struck, the operation continues on higher power factor, since the ohmic resistance of the lamp-replaces the capacitance of the electrolytic condenser which latter is removed from An inductance 33 or a resistance 34 or both, such as shown in Fig. 1 may be used for the same purpose, if desired, in the embodiment i 7 Fig; 2.

As many changes could be made in the above circuit, and many apparently widely different emintended that all matter contained in the above description or shown in the accompanying draw- Sing shall be interpreted as illustrative and not in a limiting sense.

"Having thus described our invention, what we claim as new and desire cut is: v

l. A starting and operating circuit for gaseous electricdischarge devices equipped with spaced electrodes, comprising I an electric condenser bridging across said electrodes, an electrolytic if it be of the impregnated paper dielectric type.

v The choke coil is of cost but a fraction of. that of transformersor auto-transformersof the type used to step up voltage and its operating cost also is less because of lesser wattage loss. Yet

the circuit set forth accomplishes all of the It inherentlyafpermit starting, and the circuit inherently operates on the desired high power factor, and it does this in the absence of special costly devices for power factor correction, such as for instance a highcapacity electrostatic condenser which is a put across the line asd must remain permanently in circuit. r

If desired the circuit may have an inductive reactance 33 in lead it to reduce the ratio connected to the respective mains 21 and 28 in one or which is the inductive or choke coil 29. Theelectric condenser 30 is connected across the electrodes and 28, and the electrolytic condenser ii of higher capacitance is likewise con'- nected across said electrodes and has'the switch 32 (corresponding to switch 23 of Fig. 1) in series therewith.

As in the embodiment of Fig. condenser determines the available voltag'eacross the terminals of the lamp in operation, while. condenser 3| increases the voltage to the value necessary in order to start the lamp. As a-consequence,

' with said device.

,condenser having a switch in. seriestherewith and bridging across said electrodea and an inductance in series with the discharge device.

2. A starting and operating circuit for gaseous electric discharge devices equipped with spaced electrodes, comprising an electric condenser bridging across said electrodes, an electrolytic condenser having a switch in series therewith and bridging across said electrodes and an inductance in series with the discharge device, and means foropening'said switch when the cricuit current has suificiently built up to permit the discharge'device to are over. v

3. A starting and operating circuit for gaseous electric discharge devices equipped with spaced electrodes, comprising the combination of an electric condenser across said electrodes, an electrolytic condenser 01' higher capacitance having a switch in series therewith and connected across said discharge device, and a ballast coil in series 4. A starting and operating circuit for gaseous electric discharge devices having a pair of cathodes equipped with heater filaments, an inductive reactance in serieswith said discharge device, a condenser connected across said dischargedevice, and a second condenser having a switch in "series therewith and connecting said filaments in said discharge device, and a pair of condensers connected in parallel and bridging across said cathodes, one of said condensers beingof the paper dielectric type and the other being of higher capacitance and or the electrolytic type, and a switch responsive to apredetermined current the voltage across the cold cathodes promptly and in series with the latter condenser.

6. A starting and operating circuit for gaseous electric discharge devices equipped with spaced electrodes, comprising the combination of an electric condenser across said electrodes, an electrolytic condenser of higher capacitance having a switchin series therewith and connected across to secure by Letters Pata,sse,sov V 3 said discharle device. a ballast coil in series with said device and an inductance interposed between said electriccondenser and one of said electrodes.

'1. A stertin: and operating circuit tor gaseous electricdischarse devices equipped with spaced electrodes. comprisins the combination or an electric condenser across said an elec trolytic condenser oi hither capacitance having o. switch and a resistance in series therewith and connected across said dischlusedevice. and a. bal- 5 last coil in serieswith said device. Y

ADOLPH WARSHER. MAYNARD A. BABB.

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