US3315123A

US3315123A - Plural fluorescent lamp starting circuit using an unignited lamp as ballast

Info

Publication number: US3315123A
Application number: US424718A
Authority: US
Inventors: Furui Shungo
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-01-18
Filing date: 1965-01-11
Publication date: 1967-04-18
Anticipated expiration: 1984-04-18

Description

Apnlv 18, 1967 SHU NGO FURUI 3,315,123

PLURAL FLUORESCENT LAMP STARTING CIRCUIT USING AN UNIGNITED LAMP AS BALLAST Filed Jan. 11, 1965 i. Y m s 15' Z B/METALL/G GLOW J'MBTEE :SWITCH j v VEN TOR HTMRNE Y5 to provide improved means and United States Patent Oihce 3,315,123 PLURAL FLUORESCENT LAMP STARTING CIRCUIT USING AN UNHGNHTED LAMP AS BALLAST Shungo Furni, Yokohama, Japan, assignor of fifty percent to Grace Thunberg, Garden Grove, Calif. Filed .lan. 11, 1965, Ser. No. 424,718 Claims priority, application Japan, Jan. 18, 1964, $9/13,5llfi 8 Claims. (Cl. 315-190) The present invention relates to a highly eificient and economical circuit arrangement and techniques useful in fluorescent lamp lighting systems.

In brief, the arrangements described herein comprise two fluorescent lighting lamps which are lit in sequence during the starting operation using a simple but new circuitry. Using this new circuitry involving a relatively high resistance (or a relatively high impedance electric conductor) across one of the lamps and the connection of a glow starter switch across each of said lamps, peculiar advantages and improved results are obtained. These advantages and improvements make it possible to operate fluorescent lamps much more economically not only from the viewpoint of initial cost of ballast fabrication, but also in more efficient use of electrical wattage during the hours of the lamp operation.

It is therefore a general object of the present invention technical arts whereby the above-mentioned advantages and results may be obtained.

A specific object of the present invention is to provide circuit arrangements and techniques whereby the mag nitude of the starting voltage may be relatively small, thereby lessening the voltage requirements of the equipment and also lessening the voltage required to be attenuated during the lit condition of the lamps.

Another specific object of the present invention is to provide improved circuit arrangement and techniques of this character whereby all starting voltage applied, may be utilized for lighting the lamps without almost any voltage attenuation, if desired.

Another specific object of the present invention is to provide improved circuit arrangements and techniques of this character whereby relatively small amount of power is required to be dissipated in a ballast element.

Another specific object of the present invention is to provide improved circuit arrangements and techniques of this character involving the use of two gaseous electric discharge lamps wherein during the starting operation essentially one of the lamps acts as a ballast for the other lamp, with the lamps being sequentially lit.

Another specific object of the present invention is to provide improved circuit arrangements and techniques for lessening electrical power charge per lamp for con snmers.

Another specific object of the present invention is to provide improved circuit arrangements and techniques of this character whereby the use of relatively low starting voltage per lamp makes it possible to prevent a dangerous excessive current flow through the lamps and ballast element in case a series capacitor is short-circuited due to malfunctioning thereof.

Another specific object of the present invention is to provide a system of this character using two glow starter switches in series and relatively low ballast voltage per lamp, whereby the malfunctioning of associated glow starter switches does not result in flow of excessive current, when, for example, the contact point of one of them becomes stuck in a circuit closing condition or position.

Another specific object of the present invention is to provide a system of this character in which automatic 3,3l5,l23 Patented Apr. 18, 1967 voltage regulation is obtained by coaction of a series capacitor, characteristics of a transformer and the lamp inductance.

Another specific object of the present invention is to provide a system of this character wherein the ballast components may be made relatively small in size, of relatively light weight, and with relatively small expense.

Another specific object of the present invention is to provide a system of this character in which the applied no-load secondary voltage of the ballast transformer may be used for dual functions: that is, to use the applied voltage for the lamp as the ballast voltage required for starting another lamp, and to use such applied voltage as the lighting voltage for itself.

Another specific object of the present invention is to provide improved circuit arrangements and techniques of this character whereby all the no-load secondary voltage of the ballast transformer may be applied and utilized for lighting the lamps without any voltage attenuation, if desired; that is, to eliminate a separate source of ballast voltage for starting and lighting the lamps.

Another specific object of the present invention is to provide a system of this character in which a good power factor, a good voltage characteristics, and a good performance may be obtained.

Still another specific object of the present invention is to provide a system of this character whereby said above mentioned objects may be applied to circuit arrangement of this character in which a number of the lamps are connected in series.

While the present invention is described specifically in connection with florescent lamps, it will be understood that the invention in its broader aspect is applicable also to the control of other devices which exhibit a so-called negative resistance characteristic.

The features of the present invention which to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of performance, together with further objects and advantages! thereof, may be best understood by reference to the following drawing, in which the figure illustrates a form of the present invention.

Referring to the figure, the same includes two fluorescent lamps 4 and 5, the lamp 4 having cathode filaments 4A, 4B at the opposite ends thereof; and likewise, cathode filaments 5A, 5B are at the opposite ends of theother lamp 5.

The filament 4A is connected to opposite terminals of a transformer winding 1A. The filaments 4A, 4B, 5A and 5B are connected in series with glow starter switches 6 and 7. A terminal 15 of coil 1B is connected through a capacitor 2 to one terminal of filament 5B, and the aforesaid capacitor 2 being shunted by a resistance 3, and the aforesaid glow starter switch 6 being shunted by a capacitor 9, and glow starter switch 7 being shunted by a capictor '10. The high resistance (or a high impedance electric conductor) 8 is connected in shunt with the lamp 4, consequently with glow starter switch 6 too, and in series with glow starter switch 7.

It will be seen from this circuit arrangement that an autotransformer is provided in which the primary winding is essentially that winding 1A between the terminals 13 and 14, and the secondary winding is essentially that winding 13 between terminals 13 and 15. All of the windings 1A and 1B are wound on the same core.

The glow starter switches 6 and 7 are both normally open type switch between contacts of which a gaseous discharge maybe produced with the resulting heating of one of the contacts, of bimetal, causing it to warp and engage the contact to thereby close the switch. When the switch is thus closed by the heat initially produced by the gaseous discharge between these contacts, the biare believed 3 metal element is then allowed to cool and in so doing returns to its initial condition and in so doing opens the switch 6 or 7. Such glow starter switches 6 and 7 per se form no part of the present invention and indeed are well known in the art and may, for example, be constructed as described in the U.S. Patent 2,680,211 of J. H. Campbell, patented June 1, 1954, and assigned on its face to General Electric Company. Such glow type starter switches may, as described in such Patent 2,680,211, comprise a glass envelope containing an ioni'z'able gas such as neon and including therein a pair of electrodes consisting of a curved bimetallic strip and operative such that in its normal condition, there is no contact between electrodes but when, however, a sufficient voltageis developed across the electrodes, a discharge occurs whichproduces heat to heat up the electrodes and cause the bimetal to move the switch contacts into engagement whereupon the switch closes and the glow ceases. When the glow thus ceases, the bimetal is allowed to cool and when it cools sufliciently the switch contacts are returned by the cooled bimetal to their initial open condition.

In the operation of the circuit arrangement shown in FIG. 1, when the switch 12 is closed, the transformer 1 is energized and the no-load secondary or starting voltage is impressed on the glow starter switch 7 by means of the high resistance resistor 8. Thereupon a gaseous discharge takes place between the contacts of glow starter switch 7 and the bimetal element of the switch begins to warp so as to move towards circuit closing position. When the switch 7 is closed, the applied starting voltage is transferred to glow starter switch 6, wherein a gaseous dis charge takes place between the contacts of the glow starter switch 6 and the bimetal element therein begins to warp so as to move towards circuit closing position. During these movements of said glow starter switch elements aforesaid, neither one of the two lamps 4 and 5 is lit.

However, when the both glow starter switches 7 and 6 close their switches, the preheating current may flow through cathode filaments 4A, 4B, 5A and 5B of the lamps 4 and 5, heating thereof. Now, as soon as the bimetal contactor of glow starter switch 7 gets cooled and opens its contact switch, the starting voltage may act in full at both cathodes of the lamp 5 to start instantaneously, and as soon as the bimetal contactor of glow starter switch 6 gets cooled and opens its contact switch, the starting voltage may act at both cathodes of the lamp 4, to start it instantly and light normally together with the lamp 5.

Thus in this operation, the lamps 5 and 4 are sequentially lit. When the lamps 5 and 4 are lit, the voltage developed across the same becomes sufficiently low enough 'to prevent the production of the gaseous discharge between the contacts of glow starter switches 7 and 6. Once thus lit, the lamps 5 and 4 may be extinguished, of course, by opening the switch 12.

In the system shown in FIG. 1, the starting voltage, i.e., the no-load secondary voltage developed across the terminals 13 and 15 is relatively small, and may be below 250 volts when the lamps 4 and 5 are of the 40 'watt preheated type fluorescent lamps (FL-40) for industrial application with enough reserve voltage for the supply line voltage drop. Typical circuit values are the following: Capacitor 2 may be 4.6 microfarads and the

capacitors

9 and 10 may be 0.006 microfarad each, which are used essentially for noise suppression. The resistance 3 may be a value of 1,000,000 ohms, and the high resistance 8 may be 10,000 ohms, and the glow starter switches 6 and 7 may be of the FG-4P type.

It will be seen that the foregoing described sequence of events occurs because of the resistance values in the circuit considering the fact that in the unlit condition, of the lamps 4 and 5 have a high resistance or impedance. Thus, the resistance 8 of 10,000 ohms assures an initial discharge between the contacts of the glow starter switch 7 before any one of the lamps is lit, and when the contacts of switch 7 close, the starting voltage may be transferred to the glow starter switch 6 to produce a gaseous discharge therein thereby to heat the bimetal contactor to warp and close its contact switch. When both glow starter switches 7 and 6 close their contact switches, it will be apparent that the preheating current may flow through cathode filaments of both lamps 4 and 5. But in case both glow switches 7 and 6 open their contact switches exactly simultaneously or at the same time, the starting voltage is insufficient, thereby neither of these lamps can Start.

On the other hand, when any one of the glow starter switches opens first, su'flicient starting voltage acts at both cathodes of the lamp to which said glow starter switch is connected and such lamps starts it instantly. Shortly thereafter as soon as the other glow starter switch opens its contact switch, the starting voltage acts at both cathodes of the other lamp to which the last-mentioned glow starter switch is connected, and starts such other lamp immediately following starting of the first-mentioned lamp. Thus, either lamp 4 or 5 may be started first followed by the starting of the other lamp depending upon whether switch 9 or switch 10 opens first.

In the foregoing example, a starting voltage of 250 volts or 125 volts per lamp has been used for 40 watt preheated type fluorescent lamps. But in the present invention, the starting voltage of the same may be reduced to as low as 200 volts, i.e., volts per 40 watt preheated type fluorescent lamp, if desired, in which with a slight increase of the value of the series capacitor 2 in order to make a rated lamp current of 0.435 ampere to flow at the rated voltage. The starting voltage of 100 volts per lamp for 40 watt preheated type fluorescent lamp is practically equivalent to the terminal lamp voltage under the normally operating condition. It means, therefore, in the present invention a possibility of eliminating the use of choke coil ballast thereby to consume and absorb the ballast voltage after the lamps are lit; or all the no-load secondary voltage of the ballast transformer may be applied and utilized for the lamps without any voltage attenuation.

As well-known, all gaseous electric discharge lamps have an inherent characteristic of requiring an extra or ballast voltage for starting them. For example, 200 volts is usually used for starting a 40 watt preheated type fluorescent lamp (FL-40), although only about 100 volts is ample enough for lighting it.

Heretofore, in general, the required ballast voltage of the 100 volts is taken from the secondary circuit of the ballast transformer, for example, in addition, and a choke coil is connected in series with the lamp to absorb the ballast voltage after the lamp is lit, or a leakage transformer having a secondary voltage of 200 volts is used to reduce the voltage to about 100 volts as soon as the lamp is started and is lit. In either case, all of the ballast voltage is consumed and wasted in the choke coil or within the leakage transformer in addition to involving the use of expensive ballast and causing much electric losses and lowering power factor of the circuit.

For example as aforesaid, two 40 watt preheated type fluorescent lamps (FL40) 4 and 5, are connected in series as shown in FIG. 1, with a capacitor 2 in the secondary circuit of the transformer having a no-load secondary or starting voltage of 200 volts, thus supplying a lighting voltage of 100 volts for each lamp. In the system of this circuit arrangement, when starting the lamp 4, the lamp voltage of 100 volts supplied for the lamp 5 is used instantaneously as the ballast voltage required for the lamp 4; and when starting the lamp 5, the lamp voltage of 100 volts supplied for said lamp 4 is used instantly as the ballast voltage required for starting the said lamp 5; thus making the use of the supplied voltage to each lamp for dual purposes, i.e., in course of starting as a ballast voltage, and in course of lighting as a lighting voltage, for those lamps concerned. For this reason, in

the present invention, it requires two or more lamps connected in series as shown in FIG. 1, as an example.

Heretofore in general, it was believed that it was absolutely necessary to use a choke coil ballast or a leakage transformer to provide a ballast voltage for operating fluorescent lamps. Using prior art arrangements, only a portion of the supplied volt-ampere power may be utilized for fluorescent lamps, or generally speaking only about 50% of the supplied volt-ampere power may be available for the lamps. But in the present invention, it is possible to utilize even 100% of the supplied volt-ampere power for fluorescent lamps with a stabilityof the lamp current and good performance practically as the same as the ordinary stability and performance, if desired.

When two glow starter switches are used in series as shown in FIG. 2 the voltage required to operate these glow starter switches will be twice the voltage required to operate a single glow starter switch in accordance with the prior art teachings.

But if a high resistance resistor 8 is connected in shunt with the glow starter switch 6 and in series with the glow starter switch 7, as shown in FIG. 3, it is then possible to operate these series connected two glow starter switches with a starting voltage equivalent to the starting voltage to operate a single glow starter switch, i.e., to reduce the formerly required starting voltage to 50%. As shown in FIG. 2, the operating voltage required becomes twice the voltage required to operate a single switch, as the applied starting voltage is divided between two of these glow starter switches. But as shown in FIG. 3, the resistance 8 is low enough to pass the glow discharge current through to the glow starter switch 7, but at the same time high enough to sustain transmitting a voitage high enough to produce the glow discharge at its bimetal contactor therein, and also high enough to prevent a short-circuiting condition for the glow starter switch 6. When the glow starter switch 7 closes its contacts, the same starting voltage may be transferred to the second glow starter switch 6 wherein the single glow starter switch voltage may produce a gaseous glow discharge at its contacts thereby heating the bimetal contacts to warp and eventually to close the switch, thus making it possible two glow starter switches being operated with an operating voltage equivalent to that voltage required to operate a single glow starter switch, and to enable the flowing of the preheating current through cathode filaments of fluorescent lamps.

While the particular embodiments of the present invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications i may be made without departing from this invention in its broader aspect and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

1. In a fluorescent lamp circuit arrangement, a first fluorescent lamp; a second fluorescent lamp; each of said lamps having filamentary cathodes; means for heating said cathode filaments; a first glow starter switch; a second glow starter switch; said first glow starter switch being connected in parallel with said first lamp; said second glow starter switch being connected in parallel with said second lamp; said glow starter switches being a normally open switch and incorporating means whereby heat from a glow discharge in said glow starter switch causes said switches to close; a first impedance element connected in parallel with said first lamp; said first lamp being connected in series with said second lamp; said first glow starter switch being connected in series with said second glow starter switch; said first impedance element being connected in series with said second glow start r switch; a voltage source; means for energizing said voltage source; a second impedance; said voltage source, said second impedance element and said first and second lamps being connected in series circuit; said first impedance element being effective to prevent lighting of said second lamp when said voltage source is initially energized by said energizing means with said first impedance element being effective to cause a glow discharge to appear in said second glow starter switch; said second glow starter switch being closed by heat produced by glow discharge therein to connect said voltage source to said first glOW starter switch to cause a giow discharge to appear in said first glow starter switch; when both contacts of said second and said first glow starter switches close, said voltage source causes a preheating current flow through said cathode filaments of said first and second lamps; when said second glow starter switch opens said voltage source acts at both cathodes of said second lamp to light the same; when said first glow starter switch opens its contacts said voltage source acts at both cathodes of said first lamp to light the same and thereafter the same remains lit together with said second lamp.

2. A system as set forth in claim 1, in which said first impedance element comprises a high impedance.

3. A system as set forth in claim 1, in which said second impedance element comprises a capacitor shunted by a high resistance.

4. A system as set forth in claim 1, in which said glow starter switches are each shunted by a small capacitor.

5. A system as set forth in claim 1, in which should said first glow starter switch open its contacts first, then said contacts of said second glow starter switch open next, thereby reversing the sequence of the lighting of said lamps.

6. A system as set forth in claim I, in which said fluorescent lamps have non-filamentary cathodes, whereby said first glow starter switch may be omitted.

7. In a system of the character described, a first discharge device; a second discharge device; each of said devices having filamentary cathodes; a first glow starter switch connected in parallel with said first device; a second glow starter switch connected in parallel with said second device; a first impedance element; said first impedance being connected in parallel with said first device, and being connectable in series with said second glow starter switch; a second impedance element; a transformer winding; means for energizing said transformer winding; a series circuit which includes said transformer winding, said second impedance element and said first and second devices; said first impedance element being of sufficient magnitude such that when said transformer winding is initially energized said first impedance element prevents a discharge from appearing in said second device and causes a glow discharge to appear in said second glow starter switch which incorporates whereby the heat produced by said glow discharge therein causes said switch to close and thereby effectively transfer the voltage induced in said transformer winding to said first glow starter switch to produce a glow discharge therein and to close said switch; when both said second and first glow starter switches close their contacts preheating current flows through cathode filaments of said devices thereof; as one of said glow starter switches opens its contacts therein first, said induced voltage acts on both cathodes of said device to which said glow starter switch is connected to light it instantaneously; and as the other glow starter switch opens its contact point the-rein next, said induced voltage acts on both cathodes of said device to which said other glow starter switch is connected to light it.

8. In a system of the character described, a first discharge device; a second discharge device; each of said devices having non-filamentary cathodes; a first impedance element; a glow starter switch; said first impedance element being connected in parallel with first device; said glow starter switch being connected in parallel with said second device; said glow starter switch being a normally open switch and incorporating means whereby heat from a glow discharge in said glow starter switch causes said switch to close; said first device being connected in series with second device, said first impedance element being connectable in series with said glow starter switch; a second impedance element; a transformer winding; means for energizing said transformer winding; a series circuit which includes said transformer winding, said second impedance element and said first and second devices; said first impedance element being of sutficient magnitude such that when said transformer winding is initially energized said first impedance element prevents a discharge from appearing in said second discharge device and causes a glow discharge to appear in said glow starter switch which incorporates means whereby the heat produced by said glow discharge therein causes said switch to close and thereby efiectively transfer the voltage induced in said 15 transformer winding to said first device to cause it to start; when said glow starter switch opens its contact point being cooled due to disappearance of said glow discharge, the induced voltage acts on both cathodes of said second device to cause it to start next.

References Cited by the Examiner UNITED STATES PATENTS 2,300,963 11/1942 Prescott 315100 2,363,868 11/1944 Karash 315--10O 2,518,767 8/1950 Freeman 315-97 2,680,211 6/1954 Campbell 315-189 3,038,103 6/1962 Grecu 315-100 3,155,875 11/1964 Wenrich 315100 JAMES W. LAWRENCE, Primary Examiner.

GEORGE W. WESTBY, S. D. SCHLOSSER,

Assistant Examiners.

Claims

1. IN A FLUORESCENT LAMP CIRCUIT ARRANGEMENT, A FIRST FLUORESCENT LAMP; A SECOND FLUORESCENT LAMP; EACH OF SAID LAMPS HAVING FILAMENTARY CATHODES; MEANS FOR HEATING SAID CATHODE FILAMENTS; A FIRST GLOW STARTER SWITCH; A SECOND GLOW STARTER SWITCH; SAID FIRST GLOW STARTER SWITCH BEING CONNECTED IN PARALLEL WITH SAID FIRST LAMP; SAID SECOND GLOW STARTER SWITCH BEING CONNECTED IN PARALLEL WITH SAID SECOND LAMP; SAID GLOW STARTER SWITCHES BEING A NORMALLY OPEN SWITCH AND INCORPORATING MEANS WHEREBY HEAT FROM A GLOW DISCHARGE IN SAID GLOW STARTER SWITCH CAUSES SAID SWITCHES TO CLOSE; A FIRST IMPEDANCE ELEMENT CONNECTED IN PARALLEL WITH SAID FIRST LAMP; SAID FIRST LAMP BEING CONNECTED IN SERIES WITH SAID SECOND LAMP; SAID FIRST GLOW STARTER SWITCH BEING CONNECTED IN SERIES WITH SAID SECOND GLOW STARTER SWITCH; SAID FIRST IMPEDANCE ELEMENT BEING CONNECTED IN SERIES WITH SAID SECOND GLOW STARTER SWITCH; A VOLTAGE SOURCE; MEANS FOR ENERGIZING SAID VOLTAGE SOURCE; A SECOND IMPEDANCE; SAID VOLTAGE SOURCE, SAID SECOND IMPEDANCE ELEMENT AND SAID FIRST AND SECOND LAMPS BEING CONNECTED IN SERIES CIRCUIT; SAID FIRST IMPEDANCE ELE-