US2337992A - High power factor high intensity lamp circuit - Google Patents

Description

1943- w. c.- HALL. JR., ETAL 2,337,992

HIGH POWER FACTOR HIGH INTENSITY LAMP CIRCUIT Fil ed Jan. 14, 1942 2 Sheets-Sheet 1 I ZNVENT'QRS, 39 Mun)? C. HELL/UTE. 82 E vsrsrr 1.. LEGETTEY Dec. 28, 1943. w. c. HALL, JR..IET AL 2,337,992

HIGH POWER FACTOR HIGH INTENSITY LAME CIRCUIT Filed Jan. 14, 1942 2 Sheets-Sheet 2 \u gnu u f 53 54 -74 j \n u /46 59 60 'Hl nu nu Hrry,

Patented Dec. 28, 1943 HIGH POWER FACTOR HIGH INTENSITY LAMP CIRCUIT Willard C. Hall, Jr., and Everett L. Le Gette, Los Angeles, Calif., assignors to Alfred P. Daniels,

Los Angeles, Calif.

Application January 14, 1942, Serial No. 426,748

8 Claims.

This invention relates to an electric circuit for maintaining gaseous electric discharge lamps at a high power factor as well as at a high light intensity without sacrificing the normal life span of the lamps. The invention is applicable to all forms of gaseous lamps, low or high pressure types including sodiumvapor, mercury vapor, and many other types of electrical discharge devices. The well known fiuorescent tubular lamp has end cathodes which, when in full operation, have but a single emissive, glow or hot spot, the single hot spots of the pair of spaced cathodes forming an elongated electronic discharge column substantially the length of the lamp. This column, scarcely visible itself, brightly illuminates the fluorescent material onthe inner surface of the lamp which provides the useful light. When the hot spot is mentioned in the specification and claims, the glow portion or that portion which freely emits the electrons of the cathodes is intended.

In this invention, the light quantity of an ordinary fluorescent lamp is substantially doubled.

Instead of maintaining a single hot spot on each cathode, two or more are maintained on each cathode so as to form a. stronger electronic discharge column and hence activate the fluorescent material on the inner walls of the lamp to a much greater degree with the result that the light radiation is substantially doubled. The circuit employed with the double spot cathodes consists of various transformer arrangements, automatic switch, and choke coils, the elements of the circuit being so arranged with the lamp load so as to maintain a satisfactory power factor.

One of the principal objects of this invention is to present an economical control circuit for double spotted or double emissive spotted cathode gaseous discharge lamps, the circuit comprising an arrangement of transformer coils which are automatically varied in their relation to one another so as to start and maintain the lamp at a high power factor and high intensity light value.

Another object is to work gaseous electric discharge lamps at super luminosity in an economical and efficient manner without shortening the normal life span of the lamp, or in working the lamp at normal luminosity at a much greater life span.

Other objects, advantages and features of our invention will appear from the accompanying drawings, the subjoined detailed description, the preamble of this specification, and the appended claims.

Applicants are about to illustrate and describe three forms of their invention in order to teach one how to make, use and vend the same, but it is to be understood that the drawings and description thereof are not to limit the invention in any sense whatsoever, except as limited by the appended claims.

In the drawings:

Fig. 1 is a schematic wiring diagram showin one form of the invention.

Fig. la is a cross section taken substantially along the line la-la of Fig. 1.

Fig. 2 is a schematic wiring diagram showing another form of the invention.

Fig. 3 is a schematic wiring diagram showing still another form of the invention,

The form shown in Fig. 1 comprises a fluorescent tubular glass lamp I having coiled end cathodes 2 and 3 which are processed to form hot spots at their ends 4 and 5, and 6 and 1 respectively. The ends of the cathodes have supporting conductors, the cathode 2 having the conductors 8 and 9 and the cathode 3, the conductors l0 and Il. These conductors obviously would pass from the tube via the usual presses or glass seals, not shown. The inner surface l2 of the glass. tube is lined with a suitable fluorescent material and the tube filled with an ionizable gas at proper pressure, an art nowwell known.

Insulated copper wires l3 and I4 extend from the conductors 8 and 9, the wire l3 connecting to one side of a gas switch I5 and a secondary winding l6 of a transformer I1, and the wire l4 connecting to one side of a secondary winding l8 of a transformer 19. The opposite sides of the secondaries of transformers I1 and I9 have connection with the wires 20 and 2| respectively, which connect with the conductors II and I0 respectively of the cathode 3. The gas switch l5 includes a small condenser, not shown, across its make and break contacts.

The secondary of transformer l9 has an extended winding IS, the end of which connects with the gas switch l5. This winding may be named thestarter winding.

The primary winding of transformer I1 is indicated at 23 and has end wires 24 and 25 which connect with the main feeder wires 26 and 2! respectively. These feeder wires lead to a source of suitable electric current, not shown, through the choke coil 28 and hand switch 29. The primary winding 30 of the other transformer l9 has its ends connected across the feeders 2B and 21 a shown. a

Although a manual operated switch may be j and do not appear at the terminal. drop across the tube is proportional, by a ratio, j' to the current density of the tube.

jv the drop is approximately 90 volts. drop will improve the power factor.

stood by using the following example:

volts.

to the increased current. fluorescent coating in the tube. Tubes are coated used instead of the gas switch I5, it is obviously preferable to use an automatic gas switch. The nature of this switch I is such that it will automatically close in a few seconds after the manual switch 29 is closed and hence connects the end of winding IS? with one side of cathode 2 and one side of secondary l5, so as to bring the cathodes 2 and 3 in series with the secondary windings l8 and I6 respectively of the transformers as well as with the starter winding It. This causes the cathodes to heat so that they can readily emit electrons when a conductive column is formed between them. In a few seconds, the gas switch l5 automatically opens and the tube or lamp strikes. This general operation of the gas switch for such lamps is set forth in the patent to E. C. Dench, issued May 14, 1940, and bearing Number 2,200,443.

Starting is accomplished by closing switch 29,

, this causing the switch [5 to close and the cathodes to become heated in series with their respective windings. The gas switch I 5 is set to icloseat about 138 volts, coils l6 and I8 are 'than enough to close gas switch I5. When the switch I5 opens, in phase voltage is fed to both "sides of each cathode, and the kick back of coils l8 and I9 is suificient to strike the lamp by ionizing the gas of the lamp and forming a conductive column therein. Although the lamp may "require about 187 volts to strike, its voltage drop falls to about 90, and the choke coil 28 automatically checks the current from rising to a prohibi'ted flow through the lamp.

There will be no drop across the cathode-- there is a small voltage deve1oped--.'75 voltsfrom the end of the cathode to the point of emission-there being some resistance between these points. However, they are out of phase, The voltage In this case This lower Improved power factor can be better under- Let us take a transformer having a ratio of 1 to 2 and connect the primary to the line of 120 volts, that would be 240 volts on the secondary. Now if the line varies volts, the secondary will vary However, if we turn the transformer around and put 120 volts on the secondary, we would then have volts on the primary and for the 20 volt variation in the line, we would have only a 10 volt variation in primary. The fact that we have in our invention caused the tube drop to be lower we automatically take advanimprovement in power factor, and at the same time are able to pass increased current through the tube and secure greater brightness.

The high intensity (brightness being 67% above the normal circuits) is accomplished by v the flow of additional current through the tube.

The foot candles do not increase in proportion This is due to the to have a fairly wide range of resonance. However, this resonance is peaked at the normal op- 'eratingcurrents; Thus with current densities above or below normal, there is somewhat less efiiciency in the fluorescent material. In manufacture, however, tubes can be coated to resonate at higher densities and give brightness equal to twice that of regular tubes.

In this invention, however, two hot spots are formed on each cathode as indicated at 4, 5, 6 and 1. The gas columns of these spots seem to merge and form a single elongated column 3| which is electrically stronger than the column formed by single spots on the cathodes. To

maintain the spaced hot spots on the cathodes, the cathode 2 has its ends connected to the same instantaneous polarity ends 15' and iii of the transformers, andthe other cathode has its ends connected across the opposite instantaneous polarity l6" and H)" of the transformers.

After the tube I once strikes, the hot spots remain spaced apart upon their respective cathodes and do not tend to merge because the resistance across the cathode to the other spot would make a longer path for the current, thus current will always, so long as two spots are operating, flow through its own spot or the spot on its particular side of the cathode. In one ins'tant, the spots 4 and 5 are positive and the spots 6 and 1 negative; in the next instant, the polarities of both cathodes are reversed, the rate of reversals depending upon the frequency of the alternating current.

The main feeders, in regular installations, would normally have a potential drop between them of 110-115 volts which is the usual voltage for alternating current lighting circuits. The tubular lamp 1 may be a 40 watt lamp size so that when the coils l6 and I8 heat their respecti-ve cathodes, a current of about 1.0 amp. would flow through cathodes 2 and 3. However, when the switch I 5 opens, the lamp strikes and the current through each cathode would then be 0.820 amp. However, should a super light intensity not be required in certain installations, the main line voltage may be reduced, or the transformer ratio changed, and the lamp operated at a luminosity comparable to the light given by such lamps without double spot cathodes. In this event, the double spot cathodes would have a life much in excess of the usual single spot cathode. This invention can safely allow double the normal current to flow into the cathodes of standard fluorescent lamps, and obtain at least two thirds additional brightness and at the same time improve the power factor.

The form of the invention shown in Fig. 2 of the drawings comprises the elongated lighting tube l', same as shown in Fig. 1, having cathodes 2 and 3 These cathodes have the double hot spots 4*-5' and (S -l and conductor-supports 8-9 and I'll-4 1, respectively, as set out for the tubular lamps in Fig. 1.

An auto-transformer 32 has the usual sc-ft iron wire-core 3'3, and tWO sets of windings, 3 and 35, the winding 34 being the primary and having a lead wire 36 connecting with one side of the gas switch l5, and one end of a choke coil 3? and a tap wire 38 connecting with a manual switch 39. Main feeders 40 and 4| supply suitable electric current from a source not shown. One end of the primary has an extended winding 35' which connects with a lead Wire 22 and joins conductor H) of cathode 3.

The secondary 35 of the transformer has connection with the lead wires 43 and 24 which join the-conductors Band II respectively of the oathodes 2 and 3. The secondary 35 has anextended winding 35', a lead wire from which connects with the gas switch I5.

The operation of this form of the invention is quite similar to the form shown in Fig. 1. The gas switch l5 soon closes when hand switch 39 is closed. This places winding 34 in series with the cathode 3 to heat it, and winding 35 in series with cathode 2 to heat it. When the switch l5 automatically opens, the lamp strikes. Since the cathodes have double emissive or hot spots, both hot spots will perform regularly and not merge for the reason that both ends of each cathode have inphase voltages.

The form of the invention shown in Fig. 3 comprises two fluorescent tubes 1 and I, like the ones shown in Figs. 1 and 2, and each have the end cathodes 2 and 3, double hot spots and the conductor- supports 8, 9, l and H for the cathodes.

The numeral 45 indicates the laminated core of a three limbed transformer havin a large cross sectional center limb 46 and end smaller crosssectional limbs 41 and 48. The center limb has a primary winding 49 with end leads 59 and connected to a source of suitable electric current, not shown, through a hand switch 52.

The upper limb of the transformer has two secondary windings 53 and 54 and a starter winding 54'; the ends of windings 53 being connected to wires 55 and 56 leading to the gas switch [5 and cathodes 2 and 3 of lamp l as shown. The ends of winding 54 are connected to wires 51 and 58 which lead to the opposite sides of the oathodes 2 and 3 of the lamp l as shown. Winding 54 has an extension winding 54' which connects with the switch I5.

The lower limb 48 of the transformer also has two windings indicated by the numerals 59 and 66. Wires 6| and 62 lead from the ends of the winding 59 and make connection with the oathodes 2 and 3 of lamp I, and the wires 63 and 64 connected to the ends of winding 66 lead to the opposite sides of the cathodes 2 and 3 of lamp l and lead 64 also connecting with the gas switch l5 which is the same as switch I5 as shown. Wind 59 has an extended winding 59' which connects with the switch Hi.

In practice, the coils 53 and 54 would be wound together on limb 41 for close coupling, and the same would be true for the coils on the limb 48. For purposes of clarity, the coils are shown separated on their respective transformer limbs.

The operation of this third form of the invention is as follows: When the usual hand switch 52 is closed, the gas switches l5 and I5 soon close. This places the windings 54 and 59 in series with their respective cathodes 2 and 3 of lamps l and 1 respectively, and heats them. Windings 53 and 60 likewise heat cathodes 3 and 2 of lamps l and I respectively. In a few seconds, the gas switches l5 and I5 open and their respective starter coils strike the lamps l and I; the cathodes of which are then maintained heated with double spots by electronic bombardment, since the coils 53 and 54 supply inphase current to the opposite sides of each cathode in lamp l, and the coils 59 and 60 supply inphase current to opposite sides of each cathode in lamp I. The windings of each lamp thus function in the manner set forth in the other forms of this invention.

Having thus described our invention, what is claimed as new and desired to be secured by Le ters Patent is:

1. In combination, a gaseous electric discharge lamp, a plurality of secondary transformer windlngs, and switching means; a cathode at each end of the lamp having end leads extending exterior 1y of the lamp, instantaneous like polarity ends of the windings having connection across one of the cathodes and the opposite ends of the windings having connection across the other cathode, said switch having connection with the transformer windings to momentarily connect certain of the cathodes and windings in series relation to preheat the cathodes, and then break this connection to allow the cathodes to electronically discharge between them.

2. In combination, a gaseous electric discharge lamp having cathodes with a plurality of hot spots and a circuit therefor having a switch and transformer windings, one of the cathodes having connection across the windings having like polarity points and the other cathode having connection across the windings having opposite like polarity points, said switch having connection with one of the windings and one of the cathodes so that when the switch is closed, the windings momentarily heat the cathodes, for later production of electronic illumination.

3. In combination, a gaseous electric discharge lamp having cathodes with a plurality of hot spots and a circuit therefor having a switch, condenser and transformer windings, one of the cathodes having connection across the windings having like polarity ends and the other cathode having connection across the windings having opposite like polarity ends, said switch having a connection in the circuit to place two of the cathodes momentarily in series for preheating them preparatory to normal operation of the lamp.

4. The combination of a transformer circuit and a gaseous electric discharge lamp having a plurality of electrodes, conductors leading from like polarity parts of the transformer circuit to the ends of one electrode, and the other conductors leading from opposite like polarity parts of the transformer circuit connecting to another of the electrodes, and switching means for momentarily connecting two of the electrodes in series for the prior conditioning of the lamp for normal operation.

5. The combination recited in claim 4 wherein the transformer circuit comprises a plurality of independent windings on a common iron core arrangement.

6. The combination recited in claim 4 wherein the transformer circuit comprises a pair of isolated transformers.

'7. The combination recited in claim 4 wherein the circuit comprises two separate transformers with a common central leg.

8. A circuit comprising a set of coil units in parallel with the electrodes of a gaseous electric discharge lamp load, a voltage booster winding and switch in series connected across the outof-phase ends of the coil units, one of the electrodes having its ends connected across the like polarity ends of the coil units, and the other electrode having its ends connected across the opposite like polarity ends of the coil units, said switch operating to cause preheating of the electrodes at start of the lamp load and then to stop preheating of the lamp load and allowing it to continue in operation on electronic discharge alone.

WILLARD C. HALL, JR. EVERETT L. LE GETTE

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