US2900577A - Ballast and lighting system for fluorescent lamps - Google Patents

Description

1959 Q A. E. FEINBERG 2,900,577

BALLAST AND LIGHTING SYSTEM FOR FLUORESCENT LAMPS Filed Nov. 5, 1955 2 Sheets-Sheet 1 Aug. 18, 1959 A. E. FEINBERG BALLAST AND LIGHTING SYSTEM FOR FLUORESCENT LAMPS 2 Sheets-Shet 2 Filed Nov. 3, 1955 taes 2,900,577 Patented Aug. 18, 1959 BALLAST AND LIGHTING SYSTEM FOR FLUGRESCENT LAMPS Albert E. Feinherg, Chicago, Ill.

Application November 3, 1955, Serial No. 546,413

7 Claims. (Cl. 315257) This invention relates generally to gaseous discharge device apparatus and more particularly is concerned with transformers or ballasts as they are known, for initiating and subsequently operating systems which include fluorescent lamps.

This is a continuation-impart of my application having the same title as this, Serial No. 372,310 filed August 4, 1953, now Patent No. 2,820,180.

The instant invention has in common with that described in the said co -pending application the basic circuitry for the solution of several problems described in the prior application with respect to safety and the assistance in starting. Additionally this invention has greatly improved structure for aids in starting the so-called rapid start lamps.

The rapid start lamp is primarily a low pressure gaseous discharge device and subject to several of the peculiar characteristics inherent in such devices: it operates. at a voltage substantially lower than that required to ignite the same; it will destroy itself if not in some way ballasted after ignition thereof since it is a negative resistance device and the current of operation increases greatly. It has been discovered that the discharge of a device of this kind is initiated at least in two phases, the first of which is a high voltage low energy discharge and the second of which is a low voltage high energy discharge. Thus, if some means can be used to provide the low energy high voltage discharge the requirements of the ballast will be greatly simplified.

As an example, consider the characteristics of a commercially available rapid start lamp, 24 inches long, having approximately a 40 watt rating, and a one and one half inch diameter. The igniting voltage for such a lamp, without any aid, is approximately 205 volts. For two lamps in a series-sequence start device, the voltage is about 225 volts. If, however, a starting aid is available, the starting voltage for the lamp is only 80 volts, and about 155 for two in series. It can be seen that it is manifestly easier to build a ballast for supplying the high energy requirements at 80 volts than at 205 volts, and at 155 volts instead of 225 volts.

The advantage of the starting aid having been established it is pointed out that the starting aid voltage required for many rapid start lamps is substantially greater than the starting voltage itself. The current demands. of the aid are however less than those of the starting voltage source. In the case of the type of lamp referred to above, the starting aid voltage, at the temperature at which the lamp requires an 80 volt starting voltage, is approximately 200 volts. In the case of the series lamps, the starting aid voltage is 220 volts.

It is believed that the application of the starting aid voltage produces ionization in the gaseous discharge device which decreases the difficulty of starting, notwithstanding that the quantity of ionization may not be very great, but the theory of operation is immaterial to the invention.

One of the important objects of this invention is the provision of apparatus for igniting and thereafter operating gaseous discharge devices with the aid of a starting or high excitation potential applied to the gaseous discharge devices through a metallic object nearby, in which the starting aid potential is provided independently of the starting voltage, but through the medium of the same primary Winding, and the same core structure.

Another object of the invention is to provide a structure of the character described in which there is a winding for achieving a starting aid voltage which is coupled with the primary tobe energized thereby, but which is electrically isolated from the secondary through the medium of a high ohmage resistor rendering the apparatus safe through the limitation of flow of current to ground, this being done with no sacrifice of voltage developed in the secondary winding for starting and operating the lamps.

An important'object of the invention is the provision of apparatus which accomplishes the starting aid but which is not insulated from the fixture with which the apparatus is associated, but which is nevertheless safe by reason of the limitation of current flow to ground.

Another object of the invention is the provision of a modification of the invention which enables the apparatus to be used notwithstanding the absence of a grounded line lead.

Many other objects of the invention lie in the provision of the apparatus which comprises the application of the invention to different types of circuits, such as series sequence and lead-lag, as well as the simple circuits using single gaseous discharged devices of the rapid start type. These and other objects will certainly occur to those skilled in this particular art as a description of the invention proceeds in connection with which preferred embodiments have been diagrammatically illustrated in more or less conventional manners in the accompanying drawings. Great variation is feasible without departing from the spirit or scope of the invention.

In the drawings in which the same or related characters of reference are used throughout the several figures to designate the same or equivalent parts:

Fig. 1 is a circuit diagram showing the application of the invention to a one-lamp device requiring relatively high starting aid voltage.

Fig. 2 is a somewhat diagrammatic sectional view through an iron core transformer suitable for use in connection with the apparatus of Fig. 1.

Fig. 3 is a circuit diagram of a modified form of the invention embodied in apparatus for the starting and operating of a pair of gaseous discharge devices in series.

Figs. 4a, 4b and 4c are views similar to that of Fig. 2 of iron core transformers suitable for use in connection with the apparatus of Fig. 3.

Fig. 5 is a circuit diagram of the invention embodied in a lead-lag type of circuit.

Fig. 6 is a diagrammatical sectional view through a transformer suitable for use with the apparatus of Fig. 5.

Basically the invention resides in the provision, in addition to the circuitry described in said co-pending application, of a starting aid secondary winding coupled with the primary winding to have induced therein a voltage which is preferably of such sense relative to the igniting and operating secondary winding as to aid in igniting the gaseous discharge device or devices of the apparatus. The starting aid winding may be loosely coupled relative the primary winding, but preferably is closely coupled; economically beingwound on top of the primary winding in the same Window of the transformer. The starting aid voltage is applied between the reflector of the fixture in which the gaseous discharge device is installed (or other metallic plate grounded to the fixture and in capacitive re I 3 lation to the gaseous discharge device) and at least one end of the discharge device. There is no need to insulate the starting aid from the remainder of the system including the fixture, since .the fixture is grounded in effect, and the starting aid voltage uses this ground.

Referring first to Fig. 1, there is illustrated apparatus 10 for igniting and operating a single gaseous discharge device of the rapid start type, having filaments in the ends of the lamp L which have current flowing continuously therethrough. There is provided a primary winding P mounted on a suitable iron core which is illustrated at 12 in Fig. 2. The primary winding P is separated from the secondary ,winding S by a magnetic shunt 14, including non-magnetic gaps 16 of relatively high magnetic reluctance, so that there will be relative highleakage reactance in the secondary winding S to aid the same in ballasting the lamp L.

The primary winding P has two filament windings F and F wound upon the same, and also has a starting aid secondary winding S wound upon the same to be closely coupled therewith. The primary winding P is connected by leads 18 and 20 to the terminals 22 and 24 respectively of a source of A.C. voltage, such as for example a conventional 120 volt line. The grounded terminal is chosen as 22 which is indicated by the ground connection G connected thereto.

The winding S has one side thereof connected to the lead 20 and right hand terminal of the primary winding P, and is in series with a high ohmage resistor R whose purpose is to limit the flow of current to ground to a safe value, such as milliamperes or less. The opposite terminal of the resistor R is connected to the juncture point A which is the juncture between the lead 26 connected to the left hand terminal of the lamp L, and the left hand terminal of the secondary winding S. The right hand terminal of the lamp L is connected by way of lead 28 to the second terminal of the secondary winding S which may have a power factor condenser C in series therewith. The filaments of the lamp L are connected to the windings F and F for continuous energization. The lamp L has a reflector or other metallic member 30 arranged contiguous thereto and grounded as at G From the circuit described, one may understand that the electrode to electrode igniting and operating voltage for the lamp L is obtained only from the secondary winding S in transformer relation with the primary winding P, but isolated therefrom by means of the high ohmage resistor R and the winding S This Winding S is rendered considerably smaller by virtue of the starting aid voltage available to the lamp L as will be described below.

The starting aid secondary winding S is in autotransformer relation with the primary winding P, insofar as the starting aid metallic member 30 is concerned. For example, the circuit for providing a high starting aid voltage may be traced from ground G through lead 18, primary winding P, starting aid secondary winding S resistor R juncture point A, lead 26 to the left hand terminal of the lamp L or through secondary S, capacitor C lead 28 to right hand terminal of lamp L.

Since the reflector 30 is grounded at G the voltage of P and S A combined appears between the left hand end of the reflector 30 and the left hand electrode of the lamp L to be available for ionization. In the event that the voltage sense of the winding S is additive to those-of the.

windings P and S the sum of all three voltages appears at the right hand end of the reflector, which'of course is preferable because it decreases the physical requirements of the winding 'S Considering the requirements set forth for the T-12 lamp described above, at ordinary temperatures, the starting 'aid is in the neighborhood of 200 volts '(a characteristic stated by the manufacturer in the case of a separate stanting aid electrically insulated from the fixture, but not necessarily applicable in the use of the fixture reflector as a part of the starting aid circuit) and since the voltage of the secondary S must be 80 volts, while the primary voltage will be line voltage of 120 volts,

the starting aid secondary winding is required to provide very little if any voltage in the event winding S and primary winding P are additive. For colder temperatures, a greater electrode to electrode voltage of about 135 volts may be required to ignite and operate the lamp, and under these circumstances the starting aid voltage given by the manufacturer is 430 volts, only 255 volts of which can be provided by the primary and a minimum secondary windmg 8. The starting aid secondary winding S can thus be designed to provide the additional 175 or so volts, and the starting aid voltage applied at the right hand side of the reflector between it and the right hand electrode of the lamp L.

Since the starting aid voltage is needed only during starting of the lamp and the current flow therethrough is in any event limited by the resistor R the winding S can be made of a great number of turns of fine wire Without .materially increasing the weight and cost of the ballast.

The requirement of size and turns for the heavier wire secondary winding S (for the 40 watt T-IZ lamp referred to above, the current may be as high as 1000 milliamperes) is thereby reduced with great savings.

It often occurs that the line available is not grounded. With such a situation, a virtual ground is achieved by grounding the left hand terminal of the primary winding P through a high ohmage resistor similar to R /2 to 2% megohms for most'ordinary circuits) to the ballast canister as indicated at G -in which case the reflector 30 is also grounded to the ballast canister. The resistor R prevents flow of an unsafe current between ground G and any other part of the circuit if a person contacts the fixture and another part of the circuit. The virtual ground circuit is shown in broken lines to indicate that it and the conventional ground circuit G; are mutually exclusive.

7 Special circuit requirements may require secondary winding S to be bucking relative primary winding P and starting aid secondary winding S but none are shown here. In such case, the starting aid voltage is applied across the left hand side of the reflector and lamp from the juncture point A.

Fig. 3 illustrates the circuit diagram of apparatus for igniting and operating a pair of lamps in series. The circuit is quite similar to the circuit of Fig. 1 except that thereare three filament windings F F and F serving two lamps L and L and there is a condenser C shunting the lamp L; which is in series with lamp L The first lamp to be ignited is L and the voltage applied between its reflector 30' and the right hand electrode of the lamp is the sum of voltages of windings P, S and S. The shunting condenser C has no effect before flow of current. Once lamp L ignites and current flows, lamp L ignites either as a result of the voltage produced in condenser C alone or as a result of the condenser voltage and, starting aid voltage at the right hand end of reflector 30. The same advantages are here achieved, and the same virtual ground as described in apparatus 10 may be used.

The transformer 112 or 112 of Figs. 4a or 4b may be used with the apparatus 100. These transformers are similar to one another and to transformer 12, differing only in that transformers 112 and 112 have one more filament winding F wound on the primary winding, and transformer 112' has the starting aid secondary winding S wound on top of the secondary winding S because of demands of space. The close coupling of primary winding P and starting secondary winding S is preferred. Because of this, if necessary winding S may be placed in a window of the transformer, alongside the primary winding P as shown in Fig. 4c resulting in transformer 113. Transformers 12, 112, 112' and 113 each have the secondary S separated from the primary winding P by a shunt 14 having gaps 16. All are illustrated as having a shell type core with a pressed in central winding leg upon which the windings are disposed prior to assembly. Obviously the invention is not limited to this type of iron core structure.

Fig. 5 illustrates the application of the invention to a lead-lag circuit 200. The primary winding P, starting aid secondary winding S filament windings F F and F and the circuitry to the left of juncture point A are the same as in apparatus 100. Here, however, there is a lead secondary winding S in series with a condenser C and the lead lamp L in the lead 28, and a lagging secondary winding S in series with a lagging lamp L; in lead 29, both lamp circuits being in parallel as customary in lead-lag ballast apparatus. The primary winding P does not contribute to the operating voltage, however, and hence the secondaries S and S must provide all voltage necessary, not only for operation, but as well for electrode to electrode ignition. This latter voltage of course is reduced by virtue of starting aid voltage appearing between reflector 3th and the lamp ends.

Typical transformer structure is illustrated in Fig. 6 showing transformer 212 of the shell type, having the primary winding P, the starting aid secondary winding 8,, and the filament windings F F and F all in the same window, and separated from the other secondaries by shunts 14 and 14 ' having gaps 16 and 16. Note that the primary winding P is in the center of the transformer.

It will be noted that the conventional representation of iron cores in the drawings has been used very sparingly to keep the illustrations simple. Obviously, the electromagnetic relationship between the various windings by virtue of the iron core structure illustrated in the diagrams of the transformers will be sutficient.

It is believed that the invention should be fully appreciated and all of its advantages and features well understood without the need for further explanation. It should also be manifest that variation is possible without violation of the spirit of the invention and its teachings.

What it is desired to claim is:

1. Apparatus for igniting and operating at least one fluorescent discharge lamp which comprises, a source of relatively low AC. voltage, a fluorescent discharge lamp and a fixture supporting the same, metallic starting aid means arranged in capacitive relation to the discharge lamp and metallically connected with said fixture, a transformer having an iron core and a primary winding, and two secondary windings in electromagnetic relation thereon, the primary winding being connected across the source and having one terminal thereof metallically connected with said fixture, the first secondary winding being closely coupled with the primary winding and the second secondary winding being loosely coupled relative to the primary winding and connected in series with the fluorescent discharge lamp and having one terminal thereof making a juncture with one terminal of the fluorescent discharge lamp, a high ohmage isolating resistor in series with the first secondary winding and together therewith connected between the second terminal of the primary and the said juncture, with the first secondary winding in voltage aiding relation to the primary winding, the combined voltage of said primary and first secondary windings being applied between said metallic starting aid means and said fluorescent lamp, but excluded from the operating circuit of said lamp.

2. A structure as claimed in claim 1 in which the second secondary winding is in additive voltage relationship to the primary and first secondary windings considering a series circuit containing all of said windings, whereby during starting its voltage will aid the voltage of said primary and first secondary winding, the voltages of the three windings being applied between said metallic starting aid means and said fluorescent discharge lamp.

3. A structure as claimed in claim 1 in which the source comprises a conventional power line having a grounded side and the first terminal of said primary winding is connected to said grounded side of said line.

4. Apparatus as claimed in claim 1 in which there is a second fluorescent discharge lamp and a third secondary winding also in electromagnetic relation with the primary on said core connected in series with said second fluorescent discharge lamp and having a juncture with a ter minal of said second fluorescent discharge lamp in common with said first mentioned juncture, and there being a capacitive reactor in series with one of said second and third secondaries and connected therewith across a fluorescent discharge lamp, said metallic starting aid means being also in capacitive relation to the second fluorescent discharge lamp.

5. Apparatus as claimed in claim 4 in which the transformer core is of the shell type and the primary winding is in the center thereof together with the first secondary winding, and there are shunts on opposite sides of the primary winding and the second and third secondary windings being spaced respectively from the primary winding on opposite sides thereof by said shunts.

6. Apparatus for igniting and operating a pair of fluorescent discharge lamps which comprises, a source of relatively low A.C. voltage, a pair of series connected fluorescent discharge lamps having a common terminal and independent respective outside terminals, a fixture mounting said discharge lamps and having a metallic starting aid member arranged contiguous the discharge lamps metallically connected with the fixture, a capacitive reactor across one of said discharge lamps for causing said second discharge lamp to ignite first, an iron core transformer having a primary, and first and second secondary windings, the primary being connected across the source and having one terminal thereof metallically connected with said fixture, the second secondary winding being in series with said gaseous discharge devices connected across the outside terminals thereof and forming a juncture with at least one of said terminals, a second capacitive reactor in series with said second secondary winding, an isolating resistor of high ohmage connected in series with said first secondary winding and together therewith connected from the second terminal of the primary winding to the said juncture and the primary and first secondary winding being in voltage additive relation relative a circuit containing them in series, whereby to provide a starting voltage between said metallic starting aid member and the second fluorescent discharge lamp, the second secondary winding being loosely coupled relative to the primary winding and providing the operating voltage for said fluorescent discharge lamps exclusive of said primary and first secondary windings.

7. A structure as described in claim 6 in which the second secondary winding is in additive voltage relationship with the primary and first secondary windings considering a circuit containing all windings in series whereby the voltage of said secondary winding aids in starting said second fluorescent discharge lamp.

References Cited in the file of this patent UNITED STATES PATENTS 2,067,576 Mitscherling Jan. 12, 1937 2,252,530 Sweeny et al Aug. 12, 1941 2,269,978 Kronmiller Jan. 13, 1942 2,283,728 Gage May 19, 1942 2,354,696 Mettler Aug. 1, 1944- 2,361,0l7 Flick Oct. 24, 1944- 2,402,207 Ranney June 18, 1946 2,462,336 Ruff Feb. 22, 1949 2,465,103 Komm Mar. 22, 1949 2,504,549 Lemmers Apr. 18, 1950 2,644,107 Keiffer June 30, 1953 2,665,394 Arvidsson Jan. 5, 1954 2,666,859 Kayser Jan. 19, 1954- 2,668,259 Stutsman Feb. 2, 1954 2,683,241 Passmore July 6, 1954 Disclaimer 2,900,577.-Albert E. Feinberg, Chicago, Ill. BALLAST AND LIGHTING SY STI Jiifi li FOR FLUORESCENT LAMPS. Patent dated Aug. 18, 1959. Disclaimer filed May 24, 1963, by the assignee, Advance Tmnsfomw 00.

Hereby enters this disclaimer to claims 1, 2 and 3 of said patent.

[Ojficial Gazette August 2'7, 1963.]

Notice of Adverse Decisien in Interference In Interference N0. Ballast and lighting system for fl the patentee Was rendered. Apr. 29, 1963, as

[Oyficz'al Gazette August 20, 1963.]

to chums 1, 2 and 3.

91,562 involving Patent No. 2,900,577, A. E. Feinberg,

uorescent lamps, final decision adverse to

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