US2870378A - Apparatus for starting and operating gaseous discharge devices - Google Patents

Description

NM Km v F. w. ABRAHAMS Filed Dec. 28, 1954 APPARATUS FOR STARTING AND OPERATING GASEOUS DISCHARGE DEVICES Jan. 20, 1959 United States Patent APPARATUS FUR STARTING AND OPERATING GASEOUS DISCHARGE DEVICES Fred W. Abrahams, Chicago, 111., assignor to Advance Transformer (30., Chicago, 111., a corporation of Illinois Application December 28, 1954, Serial No. 477,989

13 Claims. (Cl. 315-97) This invention relates generally to apparatus for starting and operating gaseous discharge devices, and particularly is concerned with such a device known as a ballast, which has unusual power factor correcting ability.

Generally the invention contemplates a ballast which is intended to serve two gaseous discharge devicesfluorescent lamps in the particular application for the apparatus built in accordance with the invention-connected in series.

Objects of the invention are: the provision of a ballast in which the amount of iron and necessary copper are held to a minimum; the provision of a ballast in which power factor correction is achieved in a novel manner due to the unusual arrangement of the windings on the core; the provision of a device in which power factor correction is achieved through the use of a smaller condenser than would ordinarily be used; and the provision of a device of the character described which is intended for use with gaseous discharge devices of the rapid start type, that is, for example, fluorescent lamps in which the filaments have current flowing therein continuously.

Further important objects are: the provision of a series connected pair of gaseous discharge devices in which there is a capacitance connected across one of the devices to aid in starting and in which there is capacitive means connected across the primary winding; the provision of a power factor correcting circuit for series connected discharge devices in which there is a current limiting impedance in series with the discarge devices, but in which there is no capacitance in the operating current circuit for the lamps; the provision of a circuit for igniting and operating gaseous discharge devices in which the primary is divided into two parts each of which is coupled in different degree to the secondary winding supplying the principal voltage for the discharge devices; the provision of a gaseous discharge device apparatus in which the windings are arranged relative to a shell core in a novel manner to achieve certain beneficial results.

Other objects will appear as the description of the invention proceeds, in connection with which there has been illustrated in considerable detail a preferred embodiment of the invention demonstrating the manner in which the same is carried into practical use and application.

In the drawing, in which none of the conventional core and shunt lines are shown in order to keep the illustration uncluttered:

Fig. 1 is an electrical circuit diagram of the apparatus of the invention.

Fig. 2 is a side elevational view of the transformer portion of the apparatus illustrated in Fig. 1.

The invention resides principally in the power factor correcting circuit and in the arrangement of the windings upon the transformer core, and hence it would perhaps be best to describe first the transformer and its windings.

As seen in Fig. 1 there are three filament windings F F and F there are two primary windings P and P and there are three secondary windings S S and S The windings P and S and closely coupled together, being Patented Jan. 20, 1959 wound on top of one another in a window of the transformer core as will be seen; the windings P S and F are also closely coupled together and wound one on top of another in the second window of the transformer core; and the windings S F and F are also closely coupled together and wound one on top of the other in a window of the transformer core. The relationships between the various groups of windings will shortly be brought out.

The transformer 10 comprises a stack of identical laminations of electrical sheet steel forming an outer shell 12 of rectangular formation and an inner winding leg 14 which extends the length of the shell 10 on the interior thereof. The laminations are held together by riveting or the like as indicated at 16, and the central winding leg laminations are stamped out of the same blanks. The said central winding leg 14, after assembled with the windings, is pressed back into the rectangular shell 12, with its curved ends matingly engaging at 18 and 20 with the bridging ends 22 and 24 respectively of the shell 12. Proper seating is obtained in any suitable manner such as for example, by juxtaposed indexing notches 26.

There are several punched out portions along the core 10 between the winding leg 14 and the elongate sides 28 and 3t spaced apart by inward extensions 32 and 34 relatively narrow, and 36 and 38 relatively wide. The designated extensions are all integral with the shell 12, the former pair extending about halfway to the winding leg and there facing similarly aligned extensions 40 and 42 integral with the winding leg. The extensions 32, 34, 40 and 42 together form a magnetic shunt which will generally be designated 43, provided with non-magnetic spaced gaps S4 of high reluctance. The extensions 35 and 38 face notches 56 and 48 cut in the winding leg 14 being spaced therefrom by gaps 50 and thereby forming the magnetic shunt 52 with non-magnetic high reluctance gaps. The particular structure aids in placement of the windings on the various parts of the winding leg 14 prior to pressing same home into the core 12.

Between the shunt 43 and the bridging end 22 there are formed windows 54; between the shunts 43 and 52 there 3 are formed windows 55; and between the shunt 52 and the bridging end 24 there are formed windows 56. The windings P and S are both in the windows 54; the windings P S and F are all in windows 55; and the windings S F and F are all in windows 56. Conveniently, the winding F may be a continuation of the winding P and the winding F a continuation of winding S Connections are obtained by suitable taps.

The windings P and P actually form together a primary winding which has been split into two parts separated by the shunt 4-3 since both are in series and connected to terminals and 61. The series connection between primary parts P and P is provided by jumper 64, the right hand terminal of the primary winding P P is designated and the left hand terminal 66. The two gaseous discharge devices L and L are of the continuous current filament type, the illustration intended to designate rapid start fluorescent lamps. Each lamp has a filament at opposite ends which must be continuously energized. L has filament 67 connected by leads 68 and 69 across Winding P; which provides a voltage induced by primary winding part P and a second filament 73 connected in parallel with the filament 71 of the discharge device L Jumpers 73 and '74 are connected by respective leads 75 and 76 with filament winding F which is in transformer relation with winding S The filament 78 is connected across filament winding F by leads 79 and S0.

The secondary winding S is connected by lead 82 to terminal 66 and connects with junction point 84. Between junction point 34 and terminal 65 there is connected a power factor winding 8;, in series with a power factor condenser C This winding is of particular interest be- 3 cause of its unusual function which presently will be brought out.

The third secondary winding S is connected by way of lead 86 between junction point 84 and terminal 88 which it has in common with filament winding F The basic operating circuit is a series circuit including the two discharge devices L and L and the two secondary windings S and S in auto-transformer relationship with the primary windings P and P The series circuit extends from terminal 66, includes winding S lead 86, winding S winding F (giving an additional few volts to the series circuit for aid in starting), lead 84}, filament 73, discharge device L filament 71, jumper 73, filament 7t), discharge device L filament 67, lead 69, filament winding F to terminal 65, Note that the arrows alongside the respective windings indicate the instantaneous voltage sense which is additive as to I the windings.

There is a shunting condenser C across the discharge device L so that upon energization of the circuit the discharge device L will ignite first, after which the voltage across the condenser C will build up because of current flow. The ignitionof 1. then occurs and current by-passes through the discharge device so that the capacitive effect or" C is not in the circuit.

Now it will be seen that there are basically three sections to the transformer formed of the various grouping of windings heretofore described. The first section is composed of the first primary part P and the first secondary S The voltage induced in the secondary S contributes both as to the ignition and operation of the-discharge devices. The second primary part P and the second secondary winding S together with the filament winding F form the grouping of the second section. There is a shunt 43 between the first and second sections such that the coupling between them is loose, but not to the extent that the coupling between third and second sections is loose. The shunt 52 is better than four times as wide as shunt 43 and obviously the coupling between second section and the third section, which comprises only the third secondary winding S and the remaining filament windings, is much looser than between the first and second sections. This ratio may be even greater if desired.

The winding S is arranged as described, so that there will be a great deal of leakage reactance affecting the same during operation. This is the current limiting means required to give good regulation to the discharge devices, which have negative resistance characteristics when operating. The core is non-saturating in the vicinity of winding S to prevent distortion of wave shape.

Speaking of distortion and wave shape, for maximum light it is best to avoid capacitive current and its accompanying distortion of wave shape. Capacitive current, for example, more readily saturates iron. If a circuit which is a simple series operating circuit for a pair of gaseous discharge device L and L as here is energized in the conventional way, and it is desired to correct for power factor, it is necessary to place capacitance in series with the discharge devices. The result is a distorted current through the discharge devices with decrease in lighting efficiency.

It is believed that the novelty of the invention extends to the use of a capacitive circuit across the primary in combination with a series circuit having one discharge device shunted by a starting capacitor, but in any event, the mere use of a capacitor between the junction point 84 and terminal 65 would not be totally satisfactory. The reason is that the capacitance would have to be so high that the size and cost of the capacitor would eliminate the use of such apparatus.

Several reasons are believed to account for the high efiiciency of the apparatus of the invention, considering its'cost and size. First,- the second section serves d to isolate the primary part P and its closely coupled secondary S from the mutual inductive effects of the third section during operation. Thus a greater voltage is capable of being developed in P and S than would ordinarily be developed without the isolating section. Second, the winding S in series with the capacitor C aiiects the primary winding P P but has no distorting eifect upon the principal discharge device circuit since it is in parallel with a portion of same. Thirdly, the winding S being closely coupled with the primary P provides additive voltage for igniting and operating the discharge devices without inductive reactance of any great amount and hence need not be compensated for insofar as power factor is concerned. Furthermore, it provides additional voltage for the power factor correcting condenser C keeping its capacitance low.

The sectional separation of the windings has produced a highly desirable apparatus. The wave shape is very close to sinusoidal and saturation of the core is a minimum. The power factor correction ability, notwithstanding the small condenser used (see example below) is believed accountable by virtue of isolation of the first section from the third by the second.

A practical effect of the sectionalization as described is the making available of winding space without the necessity of crowding.

It has been found that through the use of the invention a. smaller and more economical ballast has been evolved than presently being made for the same requirements, and with an increase in lighting efliciency over others. Some attempt has been made to explain this by logical theory, but it is desired to emphasize that this has been only to aid in following the description. The invalidity of such theories, although sincere effort has been put into the working out of the same, in nowise would detract from the stature of the invention as represented by the structure described. Certainly the salutary results are due to a novel combination whose precise interaction; may be incapable of explanation even by the most learned in this empirical and complex field. Because of this, the scope of the appended claims is intended to be limited only through the consideration of the novelty of the structures described therein in the light of pertinent prior art.

It is believed that one skilled in the art to which this invention appertains will have no difliculty in readily working out the details of a working example of apparatus embodying the invention through the explanation given above, but in order to assuage any possible doubt a commercial version of the invention will be described hereinafter.

The apparatus described was intended for the ignition and operation of two 96 inch watt fluorescent lamps each of the rapid start type, rated at 893 milliamperes current, and one and one half inches in diameter (T-12). The number of turns and wire size were as follows:

P 258 turns, 19 gauge. P turns, 19 gauge. S 670 turns, 25 gauge. S 351 turns, 23 gauge. 8;; 815 turns, 23 gauge.

The filament windings were between 14 and 16 turns of 19 or 23 gauge wire.

The capacitors were:

C 5.75 mfds, 400 volts A. Q. C n, .075 mfds, 800 volts A. C.

The proportions of the drawing with respect to the dimensions of the laminations are approximately right. The long dimension was 7.8" and the wide dimension 3". The stack height was 1% inches. Gaps 44 were .027 and gaps 50 were .058".

viously all voltages are A. C.

The device operates in this manner: When the primary P P is energized, a voltage will appear across the lamp L which is sufficient to ignite the lamp L Because of the condenser C shunting the lamp L the entire voltage across both lamps will be available for the lamp L; by itself. This voltage in the particular example is approximately 515 volts. It is achieved as a result of the additive effects of the primary windings and the windings S and S Once L is ignited, current flows through the series lamp circuit, except that no current is flowing through lamp L The flow of current through the condenser C causes a voltage to appear across that condenser of sufficient value to ignite lamp L after which the condenser C is short-circuited by the low impedance of the lamp L while same is operating.

After current flows through winding S because it is separated from the remaining principal windings by a rather large shunt, a high leakage reactance develops, acting as a deterrent to current flow. This keeps the lamps from destroying themselves, limiting the current to the rated value.

The voltages in the various parts of the apparatus are of interest in that they assist in visualizing the operation of the device.

For a line voltage, that is, a voltage across the primary parts P and P combined, of 118 volts the following voltages will exist:

Across the filament windings the voltage is from 4.0 to 4.1 volts on open circuit, and this drops to 3.8 volts during operation, except for the voltage across F which was found to be 3 volts.

Line current was 2.1 amperes, lamp current was the rated 800 milliamperes, current through the primary winding was 1.7 amperes, and current through the capacitive circuit including C was 850 rnilliamperes.

The above apparatus gave excellent performance, both by way of good power factor correction and efiiciency of lighting.

It is believed that the invention has been fully described in such a manner as not to require additional explanation.

What it is desired to secure by Letters Patent of the United States is:

1. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in autotransformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, said capacitive circuit comprising a second condenser and a second secondary winding mounted on said transformer core and closely coupled to the primary winding, the capacitive circuit being in parallel with a loop including the first mentioned secondary winding combined with said gaseous discharge devices.

2. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, 21 source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in autotransformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, said capacitive circuit comprising a second condenser and second and third secondary windings, the third secondary winding being in additive voltage relation with the primary winding and first mentioned secondary winding whereby said auto-transformer relationship includes the voltage thereof.

3. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of: A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in auto-transformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, the capacitive circuit comprising a second condenser and second and third secondary windings all connected in series, the first mentioned secondary winding being connected to the capacitive circuit dividing same into two branches one being the third secondary winding and the other being the second secondary winding and second condenser in series, the third secondary winding being in voltage additive relation with the first secondary winding so that the voltage developed in said third secondary winding is available for ignition and operation in addition to those developed in said primary winding and first secondary winding.

4. Apparatus as claimed in claim 3 in which said transformer has filament windings coupled with windings thereof, and said gaseous discharge devices have filaments connected to said filament windings.

5. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in auto-transformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, the primary winding being composed of two parts, and there is a second shunt between the parts.

6. Apparatus as claimed in claim in which one part, having substantially less turns than the other, is disposed between the said other part and the said secondary winding.

7. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in auto-transformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, the primary winding being composed of two series connected parts loosely coupled together, the capacitive circuit including a second secondary winding and condenser, the second secondary winding being closely coupled to one of said parts.

8. Apparatus for igniting and thereafter providing the operating voltages for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in auto-transformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, the primary winding being composed of two series connected parts loosely coupled one to the other on said transformer core, the capacitive circuit including two additional secondary windings and a capacitor, the said additional secondary windings being closely coupled with the respective parts, and the first mentioned secondary winding being connected in additive relationship with one of said additional secondary windings.

9. Apparatus as claimed in claim 8 in which the first mentioned secondary winding is connected to the capacitive circuit dividing the same into two branches one of which consists of the additional secondary winding with which it is in additive relation.

10. Apparatus for igniting and thereafter providing the operating voita es for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of 6 which has a condenser shunting the same and the discharge devices being connected in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core, a primary winding on the core at one end thereof and connected across the source, a high leakage reactance secondary winding mounted at the other end of the core, a shunt separating the primary winding and the high leakage reactance secondary winding to provide the high leakage reactance during operation, the secondary and primary windings being in autotransformer relationship and connected across the two gaseous discharge devices in series, and a capacitive circuit connected across the primary winding for power factor correction, the core having three windows along its length, a second shunt being disposed between the first and second windows and being substantially smaller than the said first mentioned shunt which is disposed between the second and third windows, the primary Winding comprising two parts, one of which is disposed in each of the first and second windows respectively with the said first secondaryivinding in the third window.

11. Apparatus as claimed in claim 9 in which the capacitive circuit. includes a second secondarry winding which is disposed in the first window along with said one part, and a condenser in series therewith.

12. Apparatus as claimed in claim 9 in which the capacitive circuit includes second and third secondary windings disposed respectively in the first and second windows, a capacitor in series with the said second and third secondary windings, and the first secondary winding being connected in additive voltage relation only with the said second secondary winding.

13. Apparatus for igniting and thereafter providing the operating voltage for gaseous discharge devices which comprises: a pair of gaseous discharge devices one of which has a starting aid condenser shunting the same and the discharge devices being in series so that they will ignite in sequence by virtue of said condenser, a source of A. C. power of voltage less than that required to ignite either discharge device, a transformer having an elongate iron core with three winding sections thereon, the first section on one end comprising a first primary winding part and a first secondary winding, the second section in the middle comprising a second primary winding part and a second secondary winding, and the third section at the second end comprising a third secondary winding, shunts with non-magnetic gaps between sections and the shunt between second and third sections being wider than the other shunt, the primary parts being connected across the source, a power factor condenser and said first and second secondary windings being in series and together connected across the primary parts as a shunting power factor circuit, the third secondary being in series with both discharge devices and connected between one side of the source and the power factor circuit between first and secondary windings and in auto-transformer relation with both primary parts and only one of said first and second secondary windings.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2 ,8'70 1378 January 2O, 1959 Fred W0 Abrahams It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters .Patent should read as corrected below.

Column 8, lines 24 and 28, for the claim. refisrence numeral "9",, each occurrence, read m 1.0

Signed and {sealed this 5th day of May 1.9590

ism) t'test:

KARL Ha AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents Attesting Ofl'icer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,870,378 January 20., 1959 Fred W n Abrahams It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 8, lines 24 and 28, for the claim reference numeral "'9 each occurrence 9 read' PM 10 Signed and sealed this 5th day of May 1.959.

S AL) t'test:

KARL H, AXLINE ROBERT C. WATSON Commissioner of Patents

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