US1990152A - Method and apparatus for operating gaseous electric discharge devices - Google Patents

Description

1935- I w. J. WINNINGHOFF 90,152

METHOD AND APPARATUS FOR OPERATING GASEOUS ELECTRIC DISCHARGE DEVICES Filed July 19, 1932 3 Sheets-Sheet 1 INVENTO Feb. 5, 1935. w. J. WINNINGHOFF 7 1,990,152

METHQD AND APPARATUS FOR OPERATING GASEOI JS ELECTRIC DISCHARGE DEVICES Filed July 19, 1932 1 3 Sheets-Sheet 2' INVENTOR Feb. 5, 1935. l w. ,1 WINNINGHOFF 2 METHOD AND APPARATUS FOR OP ERATING GASEOUS ELECTRIC DISCHARGE DEVICES Filed July 19, 1952 :5 Sheets-sheaf; 5

Annnn I'nal operating value;

Patented Feb! 5, 1935v ,METHOD AND APPARATUS FOR OPERATING GASEOUS ELECTRIC DISCHARGE DE- VICES Wilford J. Winninghoff, South Orange, N. J., as-

signor to General Electric Vapor Lamp Com-- pany, Hoboken, N. J., a corporation of New Jersey Application July 19, 1932, Serial No. 623,452

Claims.

The present invention relates to electric gaseous discharge devices generally, and in particular to vapor are devices.

A particular object of the invention is to provide 5 an artificial light source which emits light closely approximating daylight. Another object of the invention is to provide a light source having a high luminous efliciency. A further object of my invention is to provide a light source having a 19 long useful life. Still other objects and advantages of my invention will appear from the following detailed specification or from' an inspection of the accompanying drawings.

The invention consists in the new and novel combination, and in the novel method of operation, as hereinafter set forth and claimed.

On account of the well known negative voltampere characteristic of arc discharges the use of ballast in series with gaseous discharge devices is essential where these devices are to be operated I on the usual constant potential supply circuits. This ballast has commonly consisted of an ordinarytresistance, and the energy dissipated therein has constituted a loss which has materially 5 reduced the overall luminous efficiency of the gaseous discharge device. In order to eliminate this energy loss it has been proposed heretofore to employ incandescent filament lamps in place of the usual resistance, the light from these lamps being added to that from, the discharge device, with a resulting increase in the overall luminous efiiciency. This is particularly desirable where mercury vapor is employed to support the arc discharge, since the combined spectrum ofthe mercury vapor arc and of the incandenscent lamps has been found to very closely approximate daylight. tempts were made to use incandescent lamps in series with the mercury arc it was found that they rapidly burned out, due to the fact that the current rush when the mercury arc is started is a greater overload than can be tolerated. by these lamps. As a result it has never been practicable heretofore to use incandescent lamps as ballast.

I have now discovered that this difficulty is overcome by providing both a ballast resistance and suitable incandescent lamps, with suitable means to change over from one to the other as soon as the arc current has decreased to its nor- This, of course, involves the use of dual switching means in an alternating current lamp of they well known Cooper Hewitt type if the usual ballast is provided in each anode lead. I have discovered, however, that by providing asymmetrical connections for said anodes Unfortunately, however, when atthe ballast can be concentrated in one anode lead without affecting the operation of the device,

with a resulting simplification of the operating mechanism.

For the purpose of illustrating my invention I I have shown several embodiments'thereof in the accompanying drawings, in which Fig. 1 is a schematic diagram of the circuit employed for a direct .current lamp,

Fig. 2 is a modification of the circuit of Fig. 1,

Fig. 3 is a schematic diagram of a circuit employed for an alternating current lamp,

Fig. 4 is a modifications of the circuit of Fig.-

3, and

Fig. 5 is another modification of the circuit of Fig. 3.

In these drawings, with particular reference to candescent lamps 6, ballast resistance 7 and aheating unit 8. A connection is made from a point between said lamps 6 and resistance 7 to the movable element of a magnetic relay 9 which is actuated by said inductance 5. Said movable element is normally maintained against a contact which is connected to a point between said lamps 6 and the anode 4, but is adapted to be moved by the magnetic attraction of said inductance against a contact which is connected to the line side of the heating unit 8. A bimetal lic element 10 which isassociated with said heating unit 8 normally locks said element against said movement, but is adapted to be warped out of the locking position after said heating unit has been energized for a predetermined time interval, of the order of 45 seconds. A mercury switch 11, of the type commonly called a shifter,

has one terminal thereof connected between the inductance 5 and the cathode 2, while the other terminal thereof isconnected to the starting band 3 and through a resistance 12- to a point between the lamps 6 and the resistance 7.

Upon application of a suitable direct current potential to the device of Fig. 1 current immediatelyflows through the circuit comprised by inductance 5, shifter 11,- resistances 12 and 7" and the heating unit 8. This current energizes said inductance 5 and causes it to *rotatc the shifter 11 in the usual manner, opening the aforesaid circuit. The collapsing magnetic field about said inductance thereupon .produces a voltage surge therein which is impressed upon the cathode 2, causing the initiation of the arc in the lamp 1 in a well known manner. The discharge current thereupon flows through the heating unit 8, ballast resistance 7, thence through the relay 9 to the anode 4, through the lamp 1 and then back to the source through the inductance 5. It is apparent that at this time the incandescent lamps 6 are short .circuited by the relay 9, and are thus protected from the relaout of its locking position the movable element of said relay is moved by the inductance '5 to first open the by-pass around the lamps 6 and then to short circuit the ballast resistance '7. Thus thedi'scharge current is momentarily reduced, due to the additional resistance in series therewith, but is not interrupted, after which it returns to normal, the vapor are then operating with the incandescent lamps 6 as ballast. The heating unit 8 is deenergized as soon as the relay 9 assumes this new position, allowing the bimetallic element 10 to cool. Said element is, of course, prevented'by the movable element of the relay 9 from assuming its normal position, but it will be ready to snap into its locking position as soon as the inductance 5 is deenergized with the resultant movement of said movable element of the relay 9 to its original position. Thus upon any failure of the discharge current all parts of the auxiliary apparatus are automatically reset to cause the reinitiation of the discharge in the manner hereinbefore described. If one of the incandescent lamps 6 burns out, however, this may be undesirable, since it will mean a repeated starting of -the lamp on the ballast resistance, followed by failure of the discharge ,each time the relay 9 attempts to insert the lamps 6 as ballast.

This difliculty is overcome in the circuit shown in Fig. 2. In this circuit the anode 4 is-connected to the middle contact of a single pole, double throw mercury switch 13. Said switch is mountedon a pivoted support 14, at least a portion of which consists of magnetic material, which is so placed in the field of the inductance 5 as to be attracted thereto whenever said inductance is energized. A bell crank 15 normally locks the support 14 against such movement toward the inductance 5. The terminal of said switch 13 which is normally connected to said middle terminal is connected through the ballast resistance 7 and the heaterunit 8 to the positive terminal of the source, while the other terminal of said switch is connected through said lamps 6 to said positive terminal Said heater unit 8 is located adjacent to 'a bimetallic element 10 by which said bell crank'ls can be rotated out of its locking position. The shifter 11 has its positive terminal The discharge current 11, and inductance 5, causing the shifter '11 to be 'rotated with an ensuing voltage surge which initiates the discharge in the same manner as in the circuit of Fig. 1. In this case, however, the shifter current passes through the lamps 6, and hence the starting of the mercury arc is dependent upon these incandescent lamps being intact, so that any futile starting of the mercury arc is avoided. As soon as the arc has been started the discharge current passes through the heater unit 8 and ballast resistance 7, thence through the lamp 1 and inductance 5, back to the source. The heater unit thereupon causes the bimetallic element 10 to gradually warp, with a resulting rotation of the bell crank 15 until said bellcrank releases the support 14 after a period which is sufficient to allow the mercury arc to 'reach a stable operating condition. Said support 14 is thereupon rotated by the inductance 5, causing the lamps 6 to be connected in parallel with the ballast resistance 7 and heater unit 8, with a momentary rise in the discharge current, after which the circuit through said ballast resistance 7 and heater unit 8 is opened, the mercury vapor arc lamp then operating with the-lamps 6 as ballast. The bimetallic element 10. thereupon cools and assumes its original position, leaving.

the bell crank 15- ready to rotate back to its locking position whenever the support 14 drops to its I original position. The use of the bell crank 15 thus avoids any tension in the element 10 during the cooling period, and at the same time provides instantaneous resetting of the delay mechanism as soon as the discharge current falls.

Where an alternating current lamp of the Cooper Hewitt type is used, with the ballast distributed between the two anode leads in the usual manner, it is necessary to use two relays with a single delay means, as shown in Fig. 3. The cathode 2 of this lamp is connected in a conventional manner to the midpoint of the autotransformer 16, while each of the anodes-4 is connected through a pair'of incandescent lamps 6 and a ballast resistance 7 to opposite ends of said autotransformer, a heater unit 8 also being. connected in one of said anode leads next to the ballast resistance '7. A relay 9 similar to that used in Fig. 1 is connected across one set of lamps 6.

and ballast resistance 7, so as to normally short circuit the lamps, but is adapted to be operated by the inductance 5 to short'circuit the ballast resistance 7 as soon as the bimetallic element 10 is warped out of, the way when heated by the heater unit 8. A second relay 9 is connected in a similar manner across the lamps 6 and ballast resistance 7 in the other anode lead. The shifter 11 is connected through-the resistance 12 to a point between the lamps 6 and the ballast resistance 7 in one of said anode leads.

Upon applying a suitable potential to the autotransformer 16 current flows through the shifter circuit in an obvious manner, producing'a voltage surge which initiates the vapor arc. The dis charge current thereupon flows, on alternate half cycles, from one end of said ,autotransformer; through the heater unit 8, ballast resistance 7,

and relay 9 to an anode 4, and on the other half cycles from the opposite-end of said autotransformer through a ballast resistance 7 and relay 9 to the other anodeA. Thesehalf wave currents but this operation thereof is delayed until the heater unit 8 has'heated the bimetallic element 10. sufficiently to release the movable element of the relay 9. As soon as said movable element is released the short circuit across each pair of lamps 6 is simultaneously removed, and the ballast resistances '7 are short circuited immediately thereafter, leaving the lampaas ballast. Due to the fact that the heater unit '8 is still traversed by the discharge current the element 10 is maintained in a Warped position, so that if the discharge is momentarily interrupted for any reason the relays 9 and 9' will operate immediately after the discharge is initiated, without the customary delay period. Such a'connection of the heater unit may, of course, be provided in any of the other circuits illustrated, if this mode of operation is desired.

Where desired, of course, the arrangement of the lamps 6, ballast resistance '7 and switch 13 shown in Fig. 2 may be used in each of the anode leads of the alternating current lamps of Fig. 3.' In this case the use of an interlock, such as shown in Fig. 3, between the two relays or switching means is of primeimportance, since if the resistance '7 and the lamps 6 in one anode ,lead are connected in parallel while the lamps 6 are connected alone in the other .anode lead the latter lamps are usuallyburned out.

of the autotransformer one of the relays of Fig. 3 can be eliminated, greatly simplifying the circuit, as shown in Fig. 4. In this circuit theanodes 4 of the lamp 1 are connected directly to the ends of the autotransformer 16, while the cathode 2 is connected to the midpoint, thereof through the inductance 5 in the usual manner. This shifter 11 is connected between said inductance and one of said anode leads, a'resistance 12 being included in series therewith. The starting band 3' is, of course, connected in the usual manner. The. heat-- er unit 8, ballast resistance 7, and lamps 6 are connected in series in one of the primary leads to said a'utotransformer, and the relay 9 is-connected therewith in the same manner as-in Fig. 1.

Upon application'of a suitable alternating current potential to the leads to the autotransformer 16 current immediately flows through the shifter circuit, starting the lamp 1 intooperation in the usual manner. During the period when said lamp 1 is warming upit is ballasted by the resistance '7, but after the discharge current has dropped to substantially the normal value the bimetallic element 10 is warped out of the locking position, allowing the relay 9 to open the by-pass around the lamps 6 and to short circuit said ballast resistance '7, leavingv the lamp 1 to operate with said lamps 6 as ballast.

It is sometimes desirable to operate some of the incandescent lamps directly off the autotransformer 16, thus" providing a light source which is independentv of thelamp 1. In this case there is also the advantage that lowvoltage lamps, which have a higher efiiciency for a given wattage than those of higher voltage, may be used by providing suitable taps on the autotransformer.

' With primary ballasting, such asshown inFig. 4,

. connections for the mercury vapor lamp a single there would be a large voltage variation on lamps so connected, and hence ballasting in the secondary circuit is preferred in this case. I-have now discovered that by providing asymmetrical ates in an extremely satisfactory manner. As shown in this figure the mercury vapor arc lamp 1 has one of the anodes 4 thereof connected directly to the end of an autotransformer 16, while the other anode 4 is connected to the other end of said autotransformer in exactly the same mannerthat the anode is connected to the positive terminal in Fig.2; The cathode 2 is connected through an inductance 5, not to the midpoint of said autotransformer, as is usual, but to a point nearer the end which is connected directly to the first mentioned anode 4. For example, where they overall secondary voltage is 290 volts I find it satisfactory to connect the cathode lead to a point 32 volts off center toward the direct connected anode, making the voltage on the unballasted anode 113 and that on'the ballasted anode 177 volts; With such'an unbalanced volt age arrangement I find that the current on each standard 32 volt lamps. By placing the ballast in the primary circuit In the use and operation of the apparatus shown in Fig. 5, upon application of a suitable alternating current potential to the leads to the autotransformer 16 the lamps 1'7 immediately light up, At the same time current flows through.

the shifter circuit, provided thela-mps 6 are intact, and starts the mercury vapor; arc in the manner hereinbeforedescribed. The discharge current thereupon flows on alternate half cycles to ,the unballasted anode 4, and on the other half cycles to the ballasted anode, these currents combining to produce a full wave discharge in the lamp 1. Due to the-asymmetry in the potential applied to the two anodes, and to the effect of the stabilizing inductance in the circuit, the current is substantially the same on each half cycle despite the concentration of the ballast resistance in one anode lead, so that the vapor arc lamp 1 operates in exactly the same manner as if the conventional arrangement were employed. This discharge current flowing through the heater unit 8 causes the bimetallic element 10 to gradually warp out of the locking position, so that after an interval which is sufficient for the arc ourtracts said support and causes the mercury switch 13 to place the lamps 6 in circuit and then i to cut out the ballast resistance '7,'leaving the mercury arc lamp to continue operation with incandescent lamp ballast. In case one of the lamps 6 burns out the mercury arc is, of course, extinguished and the shifter is likewise rendered inoperative, preventing futile reinitiation of the are. The lamps 1'7 continue burning, however, giving some illumination until the burned out lamp can be replaced.

With any of the circuits illustrated the lamps 6 are obviously protected against the overload to which they would otherwise be subjected during the initial operating period of the mercury arc. As a result these lamps operate satisfactorily'throughout along useful life. Moreover, due to the fact that the energy which would otherwise be dissipated in a ballast resistance is here utilized to produce light which is added to that produced by themercury arc the overall lumi- -fious efficiency of the device is obviously far higher than is obtainable from the vapor are alone. This efliciency is moreover enhanced by the use of the high efficiency 32 volt incandescent lamps. While these circuits may be used in connection with any gaseous discharge device} operating with any type of-hot or cold cathode, and are particularly useful with vapor arc discharges, the combination of the mercury arc and the incandescent lamps gives a particularly pleasing light which closely approximates daylight. Such a light is, therefore, especially useful when color values are to be discerned, as in textile mills or the like, or in general illumination where a white light is desired.

While I have described my invention by reference to certain specific structures it is to be understood that it is not limited thereto, but that various omissions, changes or substitutions, within the scope of the appended claims, may be made either in the structure, or in the method of operation, without departing from the spirit of my invention.

I claim as my invention:-

1. In combination, an electric vapor discharge device, a ballast resistance connected in series therewith, an incandescent lamp, means responsive to current flow through said device to substitute said lamp for said resistance while maintaining the circuit through said discharge device, and locking means to prevent theimmediate response of said last mentioned means.

2. In combination an electric vapor discharge device, a ballast resistance connected in series therewith, an incandescent lamp, means responsive to current flow through said device to substltute said lamp for said resistance while main- 3. In combination, an electric gaseous discharge devicej'a ballast resistance connected in series therewith, an incandescent lamp, means responsive to current flow through said device to substitute said lamp for said resistance while maintaining the circuit through said discharge device, and, means to initiate a discharge in said device, said last mentioned means being connected to a source of energy through ,said incandescent lamp, whereby it is renderedinoperative upon failure of said lamp. v

4. In combination, a gaseous discharge device having a cathode and two anodes, means to connect one of said anodes directly-to a. point in an alternating current system, meansfincluding a ballast resistance to connect the other of said anodes to a point of dilferent potential in said system, said cathode being connected to a point of intermediate potential in said system, an incandescent lamp, means responsive to, current flow in said discharge device to substitute said lamp for said resistance, and locking means toprevent the immediate response of said last mentioned means.

5. In combination, a gaseous discharge device having a cathode and two anodes, means to conpotential difference between said cathode and said first mentioned anode being appreciably less than that between said cathode and the other anode whereby the current from each anode is substantially the same as from the other, an incandescent lamp, means responsive to current flow in said device to substitute said lamp for said resistance, and locking means to prevent the immediate response of said last mentioned means.

WILFORD J. WINNINGHOFF.

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