US3037147A

US3037147A - Starting and operating circuit for a discharge device

Info

Publication number: US3037147A
Application number: US852670A
Authority: US
Inventors: Luther L Genuit; Popa John
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1959-11-13
Filing date: 1959-11-13
Publication date: 1962-05-29
Anticipated expiration: 1979-05-29

Description

May 29, 1962 l.. l.. GENulT ETAL STARTING AND OPERATING CIRCUIT FOR A DISCHARGE DEVICE 2 Sheets-Sheet 1 Filed Nov. 13, 1959 M M f. M M M m May 29, 1952 L. L.. GENUIT ETAI.

STARTING AND OPERATING CIRCUIT FOR A DISCHARGE DEVICE Filed NOV. 13, 1959 2 Sheets-Shea?l 2 INE Vol 7S 3,031,147 Patented May 29, 1962 3,037,147 STARTHNG AND GPERATHNG CHRCUT FR A UISCHARGE DEVCE Luther L. Genuit, Danvilie, Ill., and Sohn Popa, Lyndburst, Va., assignors to General Electric Company, a corporation of New Yori;

Filed Nov. 13, 1959, Ser. No. 352,67@ 9 Claims. (Cl. S15-05) rThis invention relates to circuits for starting and operating arc discharge devices on direct current from an alternating current source.

ln providing a direct current supply to arc discharge devices, such as mercury vapor lamps, it is desirable that the direct current power output at the lamp terminals be substantially stable irrespective of the usual variations in the voltage and frequency of the alternating current supply. Such a requirement must be met in applications where a light source of substantially constant luminous intensity is to be employed, as for example, in a data processingr machine for counting and sorting punched data cards and where an alternating current supply is to be used as the power source.

An exemplary circuit of the prior art is described and claimed in US. Patent No. 2,892,126 granted lune 23, i959, in the name of lohn Popa and assigned to the same assignee. A voltage multiplying and filter circuit is used in conjunction with a full-wave rectifier and anV auto-1 transformer to start and operate a discharge device. Although this circuit was generally satisfactory in its operation, it was found that slight fluctuations occurred in the luminous intensity of the discharge device as the voltage and frequency of the alternating supply were varied. This invention provides an improved circuit which utilizes a stabilized power transformer apparatus and a voltage multiplying and filter circuit which function as an oscillatory circuit during the starting condition and during the operating condition of the circuit as a filter circuit.

in a circuit used to furnish direct current to an arc discharge device employed as a constant light source it is important that the lamp starts reliably and operates at a substantially constant level of luminous intensity within the range of normal variations in line frequency and voltage. In addition, it is desirable that such circuits be readily adaptable to automatic starting, that the capacitors used in the circuit be of relatively small size and that the need for separate starting windings in the alternating current transformer used in the circuit be eliminated. Adaptability to automatic starting is a desirable feature since it results in convenience to the operator. A reduction in capacitor size and the number of transformer windings is an advantageous feature since it results in reduction in the manufacturing costs.

Accordingly, a general object of the present invention is to provide an improved circuit for starting and operating an arc discharge ldevice on direct current from an alternating current supply.

A more specific object of the invention is to provide an improved circuit that will star-t and operate an arc discharge device on direct current from an alternating current source and furnish a substantially constant direct current power supply at the terminals of the arc discharge device irrespective of normal fluctuations in the alternating current power supply voltage and frequency.

Another object of the invention is to provide an improved circuit that will reliably start an arc discharge device on direct current from an alternating current supply.

A further object of the invention is to provide an improved circuit for starting and operating an arc discharge device on direct current from an alternating current supply that is readily adaptable to automatic starting.

A more specific object of the invention is to provide an improved circuit for starting and operating an arc discharge device that willeliminate the necessity for employing a starting winding in the alternating/current transformer.

lt is still a further object of the invention to provide an improved circuitfor starting vand operating arr-arc discharge device on direct current from an alternating current supply that will employ smaller sized starting capacitors.

ln accordance with the invention, the circuit includes a novel arrangementfof a powerstabilized transformer apparatus, a capacitor connected in serieswith the secondary of the transformer, a filter capacitor, a filter reactor, a starting capacitor and a means for initiating the flow of an oscillatory current in aclosed loop comprised of the filter capacitor, the filter reactor and the starting capacitor which form a lresonant circuit tuned to oscillate at a predetermined frequency. When the transformer is energized, the filter capacitor is charged to a predetermined voltage.

In order to start the arc discharge device the oscillatoryV current is initiated by connecting the filter reactor and starting capacitor across the filter capacitor. The damped oscillation that follows in the tuned portion of the circuit provides an increased voltage at the lamp terminals. During the operating condition of the circuit a direct current power output, which is not appreciably affected by normal variations in the alternating current power supply, is supplied at the lamp terminals. Further, during the operating condition of the circuit the lfilter capacitor and the inductive reactance, which also form a part of the oscillatory discharge circuit, function to filter the pulsating direct current output of the rectifier.

In another aspect of the invention a starting capacitor is used in conjunction with a reactor having a primary winding and a secondary winding, the primary winding being in series circuit with the starting capacitor and the secondary winding being in series circuit with a recti- Y fier output terminal and a lamp terminal.

A power stabilized transformer apparatus, as the term is used herein, includes a transformer and a serially connected capacitive reactance that maintains a substantially constant power output in the secondary circuit during normal fluctuations of the supply voltage and frcquency. A normal fluctuation in the supply voltage is considered to be plus or minus ten percent and avariation of plus or minus .2 `cycle per second in the line frequency is considered to be normal. In thecircuit of the invention, the secondary' of a transformer of comparatively high leakage reactance is connected serially with a first capacitor and with the filter capacitor during a portion of the cycle to provide the requisite stabilizing elfect on the power output of the transformer.

The subject matter which we regard as our invention is set forth in the appended claims. The invention itself,

however, together with further objects and advantages thereof may be better understood by referring to the following description taken in connection with the accompanying drawings in which:A

FIG. l is a schematic circuit diagram of the powerv FIG. 3 is a schematic circuit diagram of vanother em-v bodiment of the invention in which a sealed spark gap `is employed in conjunction with a serially connected primary of a starting transformer;

FIG. 4 illustrates a curve of the instantaneous voltage at the lamp terminals for the circuit shown in FIG. 3 during starting condition;

FIG. 5 illustrates the core and coil assembly of the transformer used in the power stabilizing transformer apparatus of the circuits shown in FIGS. 1 and 3;

FIG, 6 shows the lamp watts versus line volts curves corresponding to the circuit of lFIG. 1 for constant line frequencies of 60.2, 60.0 and 59.8 cycles per second; and

FIG. 7 shows the lamp watts versus line frequency curves obtained corresponding to the circuit of FIG. 1 for constant line voltages of 103.5, 115 and 126.5 volts.

Referring now to FIGS. 1 and 3, in accordance with the invention the circuit which supplies a rectified direct current to a mercury vapor lamp 11 includes a transformer 12 having a primary winding 13 and a secondary winding 14. Although the invention will be described in connection with the high pressure mercury vapor lamp 11, which in the herein described exemplification of the invention is a lamp of 100 watts rating and designated commercially as UA-33, it is to be noted that the invention is applicable to discharge lamps generally having a negative resistance characteristic.

The high pressure mercury vapor lamp 11 is operated by an arc discharge between the electrodes (not shown). The starting voltage for the lamp used in the exemplification of this invention is in excess of 700 volts DC., while the normal operating voltage across the lamp is approximately 100 volts D.C. The operating and starting circuit in accordance with the invention must provide at the lamp terminals the required starting and operating voltages from a readily available alternating current supply source, for example, a 60 cycle, 115 volt A.C. supply. Although the circuit of the invention is used in connection with a 115 volt A.C. supply, it will be appreciated that other supply voltages can be used in connection with the circuit exemplifying the invention. In a commercial embodiment of the invention the transformer connections were designed so that the transformer could readily be connected to a 115, 208 and 220 volt A.C. power source.

A pair of

terminals

15 and 16 connect the primary winding 13 of the transformer 12 with a suitable power source (not shown). The transformer 12 includes a magnetic core 17 and the shunt 1S, which are shown schematically in FIGS. 1 and 3. The magnetic shunt 13 provides the high leakage reactance necessary to limit the current flowing in the secondary circuit and supplied to the lamp 11.

Although the secondary winding 14, as shown in FIGS. l and 3, is connected with primary Winding 13 in isolated secondary relationship, it can be readily seen that a secondary can be connected up in an autotransformer relationship so long as the necessary leakage reactance required for the current limiting effect and the requisite coupling between the primary 13 and secondary 14 for the power stabilizing effect is incorporated in the transformer design.

The secondary winding 14 is connected to one side of a capacitor 19. The other side of the capacitor 19 is connected in circuit with a bridge rectifier 20. The bridge rectifier 20 includes four half-

wave rectifying elements

21, 22, 23 and 24, a pair of

rectifier input terminals

25, 26 and a pair of direct

current output terminals

27, 23. The lamp 11 is connected across the

output terminals

27, 28 of the bridge rectifier 20 by means of the

terminal connections

29 and 30. f

Connected in series circuit between the bridge rectifier output terminal 27 and the lamp `terminal connection 30 is a filter reactor or choke 31. During the starting condition of the circuit the filter choke 31 functions as a reactor having a primary winding 32 and a secondary winding 33, which includes the turns of the primary winding 32. Further, filter choke 31 furnishes the inductive reactance required in the oscillatory circuit which is ener- Cil gized by the filter capacitor 34 connected across the

bridge output terminals

27, 28.

As shown in FIG. l, a starting capacitor 35 is connected at one end to a tap 36 at an intermediate point on the filter choke 31. As shown in FIG. 3, the starting capacitor 35 is shown connected in series with a primary winding 37. A shunting resistor 38 is provided across the starting capacitor 35 for the purpose of draining otf the charge on the capacitor 35 when the current to the starting circuit is cut off.

In the circuit illustrated in FIG. l, a momentary starting switch 39 is shown connected in series with the starting capacitor 35. The switch 39 serves as a means for closing the oscillatory loop comprised of filter capacitor 34, starting capacitor 35 and filter choke 31 during the starting condition of the circuit.

It is to be noted that the circuit of the invention is readily adaptable to an automatic switching means, such as a sealed gap 43, as shown in FIG. 3, which provides the convenience of automatic starting. The spark gap employed is of the low voltage type and breaks down when the filter capacitor 34 charges to its predetermined voltage. Although a momentary starting switch and a sealed gap are shown in the embodiments illustrated in lFIGS. 1 and 3, respectively, it should be apparent that other means for initiating the oscillatory current can be employed.

In FIG. 5 the arrangement ofthe core and coil assembly of the transformer 12 is shown in more detail. A core structure 40 is comprised of J-shaped laminations 41 stacked in alternate groups one-quarter of an inch thick to stagger the butt joints. The shunt 18 is made up of a stack of rectangular laminations 42 of thin annealed magnetic material and is disposed between the primary coil 13 and the secondary coil 14- so as to provide an air gap of .020 inch. In the illustrative example of the invention, for operation of the transformer 12 from a 60 cycle, 115 volt alternating current supply, 252 turns of .0403 inch copper wire were used in the primary coil 13 and 593 turns of .032 inch copper wire were used in the secondary coil 14.

The transformer 12 functions in conjunction with the effective capacitance in the secondary circuit as a power stabilizing apparatus. In the illustrative example of the invention a suitable value of the capacitance for the series capacitor 19 was determined experimentally after the value of the filter capacitance 34 was fixed by the filtering and starting requirements of the circuit. The determination was made by varying the voltage and frequency supplied at the

input terminals

15, 16 of the transformer 12. and taking both voltage and ampere readings at the

lamp terminals

29, 30. In this manner, a value of capacitance was selected that would provide a substantially constant power output at the

lamp terminals

29, 30.

In the circuit shown in FIG. l, a capacitance of l0 microfarads for the series capacitor 19, used in conjunction with the filter capacitor 34 of 40 microfarads, was found to produce the desired stabilizing effect in the power output. The curves for lamp watts versus line volts and line frequency for the illustrative example of the circuit shown in FIG. 1 are shown in FIGS. 6 and 7. In FIG. 6 the curves for line frequencies of 60.2, 60.0 and 59.8 cycles per second are illustrated. FIG. 7 shows the lamp watts versus line frequency curves obtained when the line voitage was held constant at 103.5, and 126.5 volts respectively. It can be seen from these curves that the power stabilizing transformer apparatus provides the circuit with a substantially constant power supply. Thus, for the circuit shown in FIG. 1 a line voltage change from 103.5 volts to 126.5 volts and a frequency change of 59.8 cycles per second to 60.2 cycles per second results in maximum variation in wattage at the lamp terminals of approximately 3.28 percent.

It is to be noted that during the starting or open circuit condition the power stabilized transformer apparatus provides a root mean square voltage of approximately 215 volts at the

rectifiedinput terminals

25, 26. Duringthe normal operating condition of the lamp a root mean square voltage of approximately 85 volts is applied atthe

rectifier input terminals

25, 26.

An advantage in using a stabilized power transformer in the circuit of the invention over a constant voltage transformer of the prior art is that the voltage supplied at the lamp input terminals can be regulated Without the use of a high resistance element in the transformer circuit with its objectionable effect on the operating efficiency of the system. It will be appreciated that in accordance with the invention the alternating current voltage supplied to rectifier will vary as required by the lamp during warm up, and will maintain a substantiallyconstant power supply at the

lamp terminals

29, 39 within the normal range of line voltage and frequency iiuctuations after the larnp4 has come up to rated load. Accordingly, the circuit of the invention is particularly suited for applications where a constant iiickerless light source is required.

The circuit shown in FG. l is operated by energizing the primary 13 of the transformer 12 while the starting switch 39 is in the open position. This is necessary in order that the filter capacitor 34 may be fully charged. If the capacitor 34 is not fully charged before the starting switch 39 is actuated, the peak voltage produced by the oscillatory portion of the circuit may be insufficient to fire the lamp 11. In a commercial embodiment of the invention a relay was employed as a momentary switching means and was actuated with a delayed action to insure that the switch (not shown) controlling the power supply to the primary 13 and the starting switch 39 controlling the oscillatory condition of the circuit were operated in proper sequence.

During one-half cycle of the applied alternating voltage when .the lamp 11is operating, input terminal 26 becomes positive with respect to the terminal 25. Accordingly, the current from the transformer 12 enters the rectifier at vterminal 26 and fiows through the rectifying element 23 and outwardly at terminal 27 to the filter choke 31 and then to the lamp terminal 30. On its return path the current enters the rectifier at terminal 28, is conducted through rectifying element 21, and leaves the rectifier at terminal 25.

On the next half cycle when the polarity is reversed, the rectifying

elements

22 and 24 become the conducting elements. The current enters the rectifier 20 at terminal and is conducted through the rectifying element 24, leaving the bridge rectifier 20 at terminal 27. On its return path the current is conducted through the rectifying element 22 and returns to the transformer secondary circuit by means of the terminal 26.

The full-wave rectifier bridge 20 functions in the usual manner to change the single phase alternating current into pulses `of unidirectional current utilizing both halves of the cycle, therectifiers 21 and 23 handling one half of the cycle and the rectiers 22 and24 the other half of the cycle. The rectifying'elements used in the illustrative example ofthe invention were silicon rectifiers rated to withstand a peak inverse voltage of 400 volts. Silicon rectifiers were used primarily because of their small size. Other types of rectifiers may be used in the practice of' the invention.

During the normal operating condition ofthe circuit in accordance withV the invention, the starting capacitor 3S of the-circuit shown in FIG. 1 and the starting capacitor- 35 and the primary Winding 37 ofthe circuit shown in FIG. 3 are not eiective in the circuit. Thus, the filter choke 31-and the filter capacitor 34 effectively function in the -f circuit to'convert the pulsating direct current output of the rectifier 20' into a smooth direct current supply.

Itis to be noted that during arportion of a half cycle when the instantaneous voltage of the filter capacitor 34 and the voltage across the rectifier terminalsZS, 26 are approximately equal, the filtery capacitor 3,4, during this portion ofthe cycle, is receiving a current flow and is in series circuit with the series capacitor 19. In accordance withV the present invention the filter capacitor 34 not only functions to filter the pulsating direct current but also appears in the secondary circuit in conjunction with the series capacitor 19 to aid in producing the stabilizing effect on the power output at the lamp terminals 29,v 30. Further, itwill be appreciated that, in addition, the filter capacitor 34 supplies energy to the starting network during the oscillatory startingperiod.

The Voltage at the

output terminals

27, 28 of the bridge rectifier 2f? would be insufficient to start the lamp 11 in the circuit illustrated in FlGS. l and 3 if somemeans were not provided to step up the voltage during the starting condition of the circuit. In accordance with the invention, the additional voltage required for starting the mercury arc lamp 11 is obtained by connecting the startingcapacitor 35 and the filter reactor 31 across the charged filter capacitor 34, thereby initiating the damped oscillatory RLC current. When the starting switch 39 is closed in the circuit of FIG. 1`or when the sealed gap 43 of FIG. 3 reaches its breakdown point, a damped oscillation occurs which provides a transient peak voltage suff ficient to start the lamp 11. The exponential decay of the damped oscillation can be minimized very readily either by employing a low resistance winding in reactor 31 or by lusing a small starting capacitance 35 to achieve a high frequency oscillation. Inthe circuit shown in FIG. l, it was found more advantageous to use the small startingrcapacitance 35.

FIGS.' 2 and 4 show the exponential decay voltage curves produced by the circuits shown in FIGS. 1 and 3 respectively, during the starting condition. It is to be noted that the voltage curve shown in FIG. 4 has a peak voltage at the point of the cycle Where the abscissa has a zero value. Since the exponential curve has a negative decrement, a maximum peak Voltage is available to start the lamp.

It can be seen from curves of FIGS. 2 and 4 that dulring the starting condition approximately twice the voltage ofthe predetermined constant value to which the filter capacitor 34 is charged appears at the

lamp terminals

29, 30. An advantage in using the transformer type of connections `shown in FIGS. 1 and 3 is that the instantaneous voltage increment contributedby the oscillatory portion Of the circuit varies directly with the number of turns in the. secondary and inversely with the num-ber of turns in thev primary. Itwili be noted that the number of turns of kthe Vreactor secondary winding is limited in View of the dual functionof the component as a filter choke during the operating condition ofthe circuit and as the inductive reactance of an oscillatory discharge circuit during the starting condition. l

In the exemplification of the invention as shown in FIG. 1, theV inductive reactance of the primary and secondary windings ,32, 33 Vwere first determined experimentally by selecting values that'provided the optimum filtering action in combination with the filter capacitor 34 for the 100 watt mercury `vapor'lamp 11 and then determining the number of turns that would provide sufiicient starting voltage. It was found that a choke coil having an inductance of 2.12 henries and 1207 turns of .0285 inch coppernwire andY placing the tap 36 at a point .on the coilto provide. 402 turns for the primary 32 gavesatisfactory resultsfor both starting and operating conditions of the circuit. Y

The circuit of FIG. l has the advantage that a standard choke .coil can be used. It is to be noted that turns of extremely fine wire cannot be used in the filter choke 31,.of the. circuit `shown in FIG. 1 since an increased resistance resultsin an increased negative decrement, whichV might result in unreliable starting. Since the maximum voltage, as shown-in the curve of FIG. 2 does not occur at the point wherethe abscis'sa .has Vazerovalue, in-v creased resistance of the filter choke 31 has the effect of reducing the instantaneous peak voltage used to start the lamp.

This difficulty is overcome in the circuit shown in FIG. 3 by connecting the primary and the secondary windings so that the current flow to the primary and secondaries are in opposite directions. Having reference now to the instantaneous voltage curve shown in FIG. 4, it will be noted that all the instantaneous values of the peak voltages are positive in value and the maximum peak voltage occurs when the value of the abscissa is zero. Accordingly, in this circuit fine copper wire can be employed in the primary winding with a resultant saving of copper.

The illustrated values of circuit components referred to herein are used to exemplify an embodiment of the applicants invention. It is to be understood, however, that the particular mercury vapor lamp and the specic values of the circuit components are given by way of illustration. In general, the invention is applicable to direct current discharge lamps having a negative resistance characteristic and requiring a starting voltage that is much greater than that used during normal operation of the lamp.

It will be appreciated that various sizes and types of direct current lamps and other modifications in circuit details, such as the arrangement of the transformer means or the rectifying means or in the filter choke will readily occur to those skilled in the art. While we have described above a particular embodiment of the invention, many modifications may be made. It is to be understood, therefore, that we intend by the appended claims to cover all such modifications that fall within the true spirit and scope of the invention.

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

l. A circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a power stabilized transformer including a primary winding, a secondary winding and a serially connected capacitor, said primary being connected in circuit with said input terminals, a rectifying means having a pair of input terminals and a pair of direct current output terminals, said input terminals being connected in circuit with said secondary, a filter capacitor connected across said direct current output terminals, a pair of lamp terminal connections; an oscillatory circuit comprising a starting capacitor and an inductive reactance connected in series circuit relationship, said starting capacitor and inductive reactance being connected in circuit with said filter capacitor and said lamp terminal connections, means for closing said oscillatory circuit to initiate the oscillatory current, said filter capacitor being initially charged and supplying energy to said oscillatory circuit, said oscillatory circuit providing a transient voltage sutiicient to start said arc discharge device, said means for closing said oscillator circuit being connected in series circuit relationship with said starting capacitor, and said filter capacitor and said inductive reactance filtering the pulsating current output of said direct current output terminals after said arc discharge device is started.

2. A circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, transformer means having a primary and a secondary, said primary being connected across said input terminals, said transformer means having suiiicient reactance for ballasting said arc discharge device during operation, a first capacitor connected in series circuit with said secondary, rectifying means including a pair of direct current output terminals and a pair of rectifier input terminals connected in circuit with said first capacitor and said secondary, a second capacitor connected across said direct current output terminals, a third capacitor connected in circuit with said second capacitor, a reactance means connected in series circuit relationship with said 8. third capacitor and comprising therewith an oscillatory circuit, means for closing said oscillatory circuit to initiate the oscillatory current, said second capacitor being initially charged and supplying energy to said oscillatory circuit, said oscillatory circuit providing a transient voltage superimposed upon the voltage of said second capacitor sufficient to start said discharge device, said means for closing said oscillatory circuit being connected in series circuit with said third capactor, and said reactance means and said second capacitor filtering the pulsating direct current output of said direct current output terminals after said discharge device is started.

3. A circuit for starting and operating an arc discharge device from direct current from a source of alternating current comprising a pair of alternating current input terminals, a high leakage reactance transformer having a primary winding and a secondary Winding, said primary winding being connected across said alternating current input terminals, rectifying means having a pair of rectifier input terminals and a pair of direct current output terminals, said rectier input terminals being connected in circuit with said secondary winding, a first capacitor connected in series circuit with said secondary winding and one of said rectifier input terminals, a second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, a filter choke connected in series circuit with one of said direct current output terminals and one of said lamp terminal connections and having a tap located at an intermediate point on said filter choke, a third capacitor, a switching means, and circuit means connecting said tap, said third capacitor and said switching means in series circuit across said lamp terminal connections, said filter choke and said third capacitor being connected in series circuit relationship and comprising a portion of an oscillatory circuit, said switching means causing said second capacitor to supply energy to said oscillatory circuit to provide a voltage sufficient to start said discharge device and remaining open after said arc discharge device has started, said filter choke and said second capacitor filtering the pulsating direct current output of the direct current output terminals of said rectifying means after said discharge device is started.

4. The circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a pair of lamp terminal connections, a transformer means having a primary and a secondary, a first capacitor connected in series with said secondary, rectifying means having a pair of rectifier input terminals and a pair of direct current output terminals, said rectifier input terminals being connected in circuit with said secondary and said I'irst capacitor, a second capacitor connected across said direct current output terminals, an inductive reactance means having a primary winding and a secondary winding, said secondary winding of said inductive reactance means being connected in series circuit between one of said lamp terminal connections and one of said direct current output terminals, a third capacitor connected in series circuit relationship with said secondary winding, said third capacitor and said reactance means comprising an oscillatory circuit, means for con necting said oscillatory circuit across said second capacitor, said means including a switch connected in series with said third capacitor and causing said second capacitor to supply energy to said oscillatory circuit and provide a transient voltage at said lamp terminal connections superimposed upon the voltage across said sec- 0nd capacitor sufcient to start said arc discharge device, said switch remaining open after said discharge device has started said inductive reactance means and said second capacitor filtering the pulsating direct current output of said direct current output terminals after said discharge device is started.

5. A circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a high reactance transformer having a primary winding and a secondary Winding, said primary winding being connected across said input terminals, a first capacitor connected in series with said secondary winding, a bridge rectifier having a pair of input terminals and a pair or direct current output terminals, said rectifier input terminals being connected in circuit with said first capacitor and said secondary Winding, a second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, an inductive reactance connected in circuit with one of said lamp terminal connections and one of said direct current output terminals, a third capacitor connected in series circuit relationship with said inductive reactance, a filter circuit comprising said second capacitor and said inductive reactance ltering the pulsating direct current output of said direct current output terminals after said arc discharge device is started, an oscillatory circuit comprising said third capacitor and said inductive reactance, switching means connected in series circuit relationship with said third capacitor and causing said second capacitor to supply energy to said oscillatory cirfcuit in order to provide at said lamp terminal connections a transient voltage superimposed upon the voltage across said second capacitor suflicient to start said .arc discharge device.

6. A circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a high reactance transformer having a primary Winding and a secondary winding, said primary winding being connected across said input terminals, a first capacitor connected in series circuit with said secondary winding, a bridge rectier having a pair of input terminals and a pair of direct current output terminals, said input terminals being connected in circuit with said first capacitor and said secondary winding, a second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, an inductive reactance means having a primary winding and a secondary Winding, said secondary winding of said inductive reactance means being connected in circuit with one of said terminal lamp connections and one of said direct current output terminals, a third capacitor connected in series circuit relationship with said primary winding of said inductive reactance means and comprising therewith an oscillatory circuit, and a switching means connected in series circuit relationship with said third capacitor for causing said second capacitor to supply energy to said oscillatory circuit to provide a transient voltage suiiicient to start said arc discharge device, said second capacitor Iand said inductive reactance means filtering said pulsating direct current output of said direct current terminals after said arc discharge device is started.

7. A :circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a first transformer having a primary winding and a secondary winding, a first capacitor connected in series circuit with said secondary winding, a bridge rectifier having a pair of rectifier input terminals and a pair of direct current output terminals, said input terminals being connected in circuit with said secondary winding and said first capacitor, a second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, `an inductive reactance connected in circuit with yone of said lamp terminal connections and one of said direct current output terminals, a third capacitor, a sealed gap means, said third capacitor and said sealed gap being serially connected in circuit `across said lamp terminal connections, said inductive reactance and said third capacitor being connected in series circuit relationship and comprising an oscillatory circuit, said sealed gap causing said second capacitor to excite said oscillatory circuit in order to provide a transient voltage sufficient to start said arc discharge device, and said inductive reactance and said second capacitor filtering the pulsating direct current `output of said direct current output terminals after said arc discharge device is started.

8. A circuit for starting and operating an arc discharge device on direct current from a source of alternating eurrent comprising a pair of alternating current input terminals, a high reactance transformer having a primary winding and a secondary winding, said primary winding being connected across said alternating current input terminals, said bridge rectitier input terminals being connected in circuit with said first capacitor and said secondary Winding, a second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, a filter choke having a tap at an intermediate point and connected in series circuit between one of said lamp .terminal connections and one of said direct current output terminals, a third capacitor, a momentary switch, said third capacitor and said momentary switch being connected in series circuit with said tap across said lamp terminal connections, said third capacitor and the portion of said filter choke between said tap and one of said direct current output terminals being in series circuit relationship and comprising an oscillatory circuit and said momentary switch when actuated causing said second capacitor to excite said oscillatory circuit to provide a transient voltage superimposed upon the voltage across said second capacitor sufficient to start said arc discharge device, said momentary switch remaining open after said arc discharge device has started, said filter choke and said second capacitor filtering said pulsating direct current output of said direct current output terminals after said arc discharge device is started.

9. A circuit for starting and operating an arc discharge device on direct current from a source of alternating current comprising a pair of alternating current input terminals, a high leakage reactance transformer having a primary winding and a secondary winding, said primary winding being connected across said input terminals, a first capacitor connected in series circuit with said secondary winding, a bridge rectifier having a pair of rectifier input terminals and a pair of direct current output terminals, said bridge rectitier input terminals lbeing connected in circuit with said first capacitor and said secondary winding, a `second capacitor connected across said direct current output terminals, a pair of lamp terminal connections, an inductive reactance means having a primary winding and a secondary winding connected in circuit between one of said lamp terminal connectionsand one of said direct current output terminals, a third capacitor, said third capacitor and said inductive reactance means comprising an oscillatory circuit and a sealed gap, said sealed gap and said third capacitor being connected in series circuit with said primary of said inductive reactance means and across said lamp terminal connections, said sealed gap causing said second capacitor to excite said oscillatory circuit to provide a transient voltage `across said lamp terminal connections sufficient to start said arc discharge device, said secondary winding and said second capacitor filtering said pulsating direct current output of said direct current output terminals after said discharge device is started.

References Cited in the file of this patent UNITED STATES PATENTS '2,717,335 Sims et al Sept. 6, 1955 2,717,337 Laird Sept. 6, 1955 2,737,612 sims Mar. 6, 1956 2,757,318 Noel et al. July 3l, 1956 FOREIGN PATENTS 618,256 Great Britain Feb. 18, 1949