US3350601A

US3350601A - Device for switching over the current feeding at least two electric discharge tubes containing an ionizable atmosphere

Info

Publication number: US3350601A
Application number: US426098A
Authority: US
Inventors: Gomonet Edouard
Original assignee: Claude Paz et Visseaux SA
Current assignee: Claude Paz et Visseaux SA
Priority date: 1964-01-30
Filing date: 1965-01-18
Publication date: 1967-10-31
Anticipated expiration: 1984-10-31
Also published as: CH422989A; BE658597A; FR1395639A; DE1227999B

Description

Oct. 31, 1967 E. GOMONET 3 350,601 DEVICE FOR SWITCHING OVER TH E CURRENT FEEDING AT LEAST TWO ELECTRIC DISCHARGE TUBES CONTAINING AN IONIZABLE ATMOSPHERE 7 Filed Jan. 18, 1965 2 Sheets-Sheet 1 Oct. 31, 1967 E. GOMONI ET I 3,350,601 DEVICE FOR SWITCHING OVER THE CURRENT FEEDING AT LEAST I TWO ELECTRIC DISCHARGE TUBES CONTAINING AN IONIZABLE ATMOSPHERE Filed Jan. 18, 1965 2 Sheets-Sheet 2 Fig. 5

United States Patent 3,350,601 DEVICE FOR SWITCHING OVER THE CURRENT FEEDING AT LEAST TWO ELECTRIC DIS- CHARGE TUBES CONTAINING AN IONIZABLE ATMOSPHERE Edouard Goinonet, Paris, France,

Claude Paz et Visseaux Filed Jan. 18, 1965, Ser. No. 426,098 Claims priority, application France, Jan. 30, 1964, 962,049, Patent 1,395,639 15 Claims. (Cl. 315-90) The present invention has for its object an arrangement for switching over the current feeding at least two electric discharge tubes containing an ionizable atmosphere, the switching being performed on one or several secondary coils of the transformer or transformers feeding said tubes, in which arrangement the switch, before it disconnects the operative discharge tube from the corresponding secondary coil, ensures the connection of another tube with the secondary coil which is to feed it.

One or more of said discharge tubes may be replaced by a group of at least two such tubes serially connected.

The shifting appearance of luminous ornamental displays and signs is generally controlled by connecting and disconnecting in accordance with a predetermined rhythm the primary coil of the transformers of which the secondary coils feed the discharge tubes forming the sources of light for ornamental display or signboard purposes.

In order to reduce the number of transformers, it has already been proposed to connect sequentially several discharge tubes or groups of discharge tubes connected in series with a same secondary coil through the agency of a switch. By reason of the high open circuit voltage of the transformers feeding the tubes and of the important energy which may be stored in said transformers at the moment of the breaking of the circuit, each time the switch is operated, an arcing generally appears in the switch. Such an arcing is prevented when the feeding of one tube is switched off only after the feeding of the next tube is provided. However, the arcing reappears as soon as a tube or group of serially connected tubes cannot be ignited, for instance when a connection is cut off or a tube is out of use. In such a case, as a matter of fact, the energy stored in the secondary coil of the transformer when it feeds a group of tubes in an operative condition, can no longer be dissipated in the next group of tubes since the latter cannot be ignited. Said energy is transformed into an intense sparking in the high voltage switch the repetition of the sparks finally damaging said switch.

According to the invention, said drawback is cured by providing an auxiliary electric discharge tube containing an ionizable atmosphere, said tube connecting together those switch contact-pieces through which the latter is connected respectively with the different discharge tubes or groups of discharge tubes.

The accompanying drawings illustrate by way of example and diagrammatically various embodiments of the invention.

In said drawings:

FIGS. 1, 2 and 3 are diagrams of an embodiment showing three switching stages,

FIG. 4 is a'diagram for the successive energizing of four groups of tubes,

FIG. 5 is a diagram incorporating a transformer provided with two secondary coils,

FIGS. 6 and 7 illustrate modifications in the connections provided for the auxiliary tube,

FIG. 8 is a diagram of a circuit which allows obtaining manifold luminous effects.

In the circuit illustrated in FIGS. 1, 2 and 3, a transformer 2 showing high magnetic leaks includes a primary coil 4 fed by a source of alternating current 6, and a secassignor to 2 ondary coil 8. Two

groups ofdischarge tubes

10, 12, 14 and 16, 18, 20 are connected in parallel with the secondary coil 8 through the agency of a high voltage switch designated by the general reference number 22. Said tubes are constituted for instance by fluorescent lamps or neon tubes.

The switch 22 includes a central contact-piece 24 connected with the secondary coil 8 and controlled for instance by a cam driven by a small motor and speed reducer group (not shown) said central contact-piece 24 being associated with two lateral contact-

pieces

26, 28 connected respectively with the tube 10 and with the tube 16 and urged against an insulating stop 34 by

corresponding springs

30 and 32.

The central contact-piece 24 plays the part of the movable contact-piece of a conventional switch while the lateral contact-

pieces

26, 28 play the part of stationary contact-pieces. Said contact-pieces will be designated hereinafter respectively as the movable contact-piece and the stationary contact-pieces.

In the switch position illustrated in FIG. 1, the movable contact-piece 24 engages the stationary contact-piece 26 and ensures the feeding of the

tubes

10, 12 and 14 while no current can pass through the group of

tubes

16, 18, 20, since the stationary contact-piece 28 corresponding thereto is prevented by the stop 34 from engaging the

contactpieces

24 and 26.

In the switch position illustrated in FIG. 2, the movable contact-piece 24 engages both stationary contact-

pieces

26 and 28 simultaneously. The stop 34 may or may not engage the stationary contact-pieces during said switch position. For the very short time, during which the two groups of tubes are connected in parallel, the current passes through both groups, however with a very unequal distribution even if the electric characteristic features of the two groups are very similar. No sparking is produced since no circuit is broken.

When the next switch position illustrated in FIG. 3 is reached, the contact-piece 24 has moved off the contactpiece 26 while remaining in contact with the contact-piece 28. The sparking in the switch is eliminated or minimized since the energy stored in the transformer may readily flow through the

tubes

16, 18 and 20.

This being done, and the switch 22 being thereafter set in succession in the positions illustrated in FIGS. 2 and 1, there is obtained simultaneously the extinction of the

group

16, 18, 20 and straightforward starting of the

group

10, 12, 14 without any sparking or with a very re duced sparking.

In order to break a contact in the switch with a minimum sparking, it is an advantage to produce an ionization in the tubes fed by the contact-piece which has just been closed. To this end, it is necessary for the tubes to have been subjected at least to one peak voltage during the period for which the two stationary contact-pieces are simultaneously closed, whatever may be the location of the moment at which the contact closes with reference to the voltage phase. This result is obtained by keeping simultaneously the two contact-pieces in their closed condition during at least one half period for example at least one hundredth of a second in the case of 50 cycle current. On the other hand, it is preferable for said duration of connection in parallel of the two groups of tubes, to be hardly perceptible for observers and therefore, it is of interest to make it at least less than one twentieth of a second.

In order to prevent any damage to the switch 22 when a series of tubes cannot be ignited, an auxiliary tube 112 is connected across the contact-

pieces

26 and 28 of the switch.

The auxiliary tube is constituted for instance by a comparatively short discharge tube with cold electrodes, con- I group of tubes taining a mass of a rare gas under a pressure of a few tens centimeters of mercury.

Assuming first that the electric system is in a proper operative condition, operation of the switching device is as follows, starting from the position illustrated in FIG. 3.

At the start, the tubes 16-, 18 and 20 are fed and the difference between the characteristic electric feature of the

groups

16, 18, 20 on the one hand and 10, 12, 14, 112 on the other hand, is such that the current in the tubes of the latter group is negligible. The operation of the switch 22 first short-circuits the tube 112 and sets in parallel the

groups

16, 18, 20 and 10, 12, 14 after which the

tubes

10, 12 and 14 remain directly connected across the terminals of the transformer while the tube 112 is inserted in series with the

tubes

16, 18, 20 so that the current in the latter is negligible, while practically all of the current passes through the

tubes

10, 12 and 14. If, on the contrary, one of the tubes, 10, 12 and 14 is no longer capable of operating, the second stage in the operation of the switch 22 would insert the tube 112 in series with

tubes

16, 18, 20 and the energy stored in the transformer would be spent in said tubes instead of producing destructive sparks in the switch 22.

In the case where it is desired to feed in succession a number n of groups of tubes inserted in series, It being an integer above 2, it is possible to design a switch similar to the switch 22, but provided in this case with n outputs. Said switch should operate in a sequence such that one is disconnected only after the switch has provided for the connection of the group which is to be ignited immediately afterwards and the case is obviously the same when one or more groups include only one tube each. It is also possible to use, as illustrated in FIG. 4, a simpler high voltage switch similar to the switch 22..

FIG. 4.illustrates an embodiment adapted to energize in succession four groups of tubes, 36+38+40,

48+50+52, 54-1-56-1-58. The two first groups are designated by the general reference 60 and the two last groups by the general reference 62.

For each system of two groups,

circuit breakers

68, 70, 72 and 74 control the connection of the groups forming the corresponding system. These circuit-breakers are actuated only during the lapse of time during which the switch 22 does not allow any current to pass through the system of groups of tubes considered. In FIG. 4, the switch 22, which has just been brought from the position for which it allows current to pass through the

group

54, 56, 58 of the system 62 has been brought into the position for which it causes current to pass through the

group

36, 38, 40 of the system 60. It is then possible to close the circuit breaker 72 and to open the circuit breaker 74 so that at the next return of the switch 22. towards the system 62, the

group

48, 50, 52 is ignited. When the switch 22 is in the position energizing the system 62, it is possible to operate the circuit-

breakers

68 and 70.

The movement of said circuit-breakers is automatic and is controlled by the same motor as the reversal of the switch 22 so that the operation of said contact-breakers is always performed reliably during a phase for which the corresponding circuits are at zero current.

An auxiliary tube 112, playing the same part as in the circuit illustrated in FIGS. 1, 2 and 3, is connected across the system 60 and 62.

It is also possible to use an auxiliary tube when several secondary coils feed the discharge tubes.

FIG. illustrates a circuit of such a type comprising a transformer showing high magnetic leaks and including a primary coil 80 and two

secondary coils

82 and 84, which latter feed respectively the corresponding groups of

tubes

86, 88, 90 and 126, 12.8, 130. The high voltage switch is constituted in the present case by a rocking mercury switch 106 carrying an amount of mercury sufiicient for shortcircuiting the extreme contact-

piece

108, 110 when the switch is in its intermediate position.

The point common to the

secondary coils

82 and 84 is grounded and an auxiliary tube 112 is connected across the

terminals

108, 110 of the switch. The secondary coil 84 is coupled with the primary coil to the same extent as the secondary coil 82.

If, starting from the position illustrated in FIG. 5, the switch rocks towards the right and assuming the

group

86, 88 and 90 is defective and cannot be ignited, the circuit is closed as follows, starting from the point common of the secondary coils:

Line 132, mass of mercury between the cooperating contact-

pieces

124 and 110,

lines

122 and 120, tube 112, line 118 and 116, the

tubes

130, 128, 126 which were ignited during the preceding stage, secondary coil 84.

In order that the switch 106 may operate properly, the magnetic coupling between the

secondaries

82 and 84 should be sufficiently close. Experience has shown that it is necessary to satisfy the relationship:

E2 075 E1 where E and E are the no-load voltages of one of the two secondary coils and of the other respectively, while E and E are the voltages obtained, when said one secondary coil feeds, after ignition, the corresponding tube or tubes, for said one and said other secondary coil respectively.

The safety obtained through the agency of the auxiliary tube 112 may be increased. For instance, it is possible to connect a similar tube in shunt across said tube; when one of the two auxiliary tubes becomes damaged or has been damaged by some accident, the other tube remains to play the part of the first tube. It is also possible to control, through the agency of the current passing in the auxiliary tube in the case of a mishap, a relay which switches off the current feeding the transformer or transformers.

FIGS. 6 and 7 illustrate, by way of example, two circuit sections for which both such supplementary safety means are used simultaneously. In both cases, the auxiliary supplementary tube is designated by the reference number 136 and the sensitive member controlling the relay acting as a circuit disconnect, such for example as a Winding or a bimetallic strip, is illustrated merely by a block 138. The portion of the circuit illustrated is substituted for the one which on FIGS. 1 to 5 includes the

switch

22 or 106, the tube 112 and their connecting wires.

In the circuit section illustrated in FIG. 6, the tube 136 is connected directly shuntwise across the tube 112', the sensitive member 138 is connected in series with both tubes and the system including the

tubes

112 and 136 and the sensitive member 138 is connected shuntwise across the extreme contact-

pieces

108 and 110 of the switch 106 under load. The sensitive member 138 functions in the event of damage to the tube 112 or the tube 136.

In the circuit section illustrated in FIG. 7, the

tubes

112 and 136 have starting voltages of different values. The sensitive member 138 is connected in series with the tube of which the starting voltage is the higher, say the tube 136. The other tube 112 is connected in shunt with the system including the tube 136 and the sensitive member 138. In case of a mishap, the auxiliary tube 112 is that which is normally ignited and it feeds current towards the luminous tubes which can start. If now said tube 112 cannot be ignited or is ignited only with difficulty, the auxiliary tube 136 is ignited and current passes then through the sensitive member 138 which switches off the feeding of energy into the transformer.

The possible embodiments of the invention may be used to produce a succession of illuminations based upon those disclosed above. It is possible to resort to a number of high voltage switches operating in the manner described with reference to FIGS. 1, 2 and 3 for instance. The circuit illustrated in FIG. 8 includes four

high voltage switches

140, 142, 144, 146 illustrated in a highly diagrammatic manner and actuated periodically by a motor and speed reducer group in accordance with a predetermined programme. It is thus possible to obtain a number of varied combinations during a cycle.

For each switch, the contact-pieces connected with different discharge tubes are interconnected by an auxiliary discharge tube. For sake of simplification of FIGURE 8, only the auxiliary tube 112 is illustrated, which tube interconnects the contact-pieces of the switch 146, said contact-pieces being connected respectively with the

tubes

148 and 150.

The circuits illustrated may be modified without departing from the present invention. For instance, the

switch

22 or 106 under load may be bipolar, for instance in the case of displays operating in the open, in damp countries. The positions of the two elementary switches for which two groups of tubes are connected simultaneously, are transiently coextant.

What I claim is:

1. An arrangement for switching from one circuit to another of a pair of circuits, each circuit containing at least one main discharge tube having an ionizable atmosphere, comprising an auxiliary tube having a pair of electrodes in an ionizable atmosphere, said auxiliary tube being connected in series with the main tubes, and switch means having a pair of terminals, one terminal being connected to one of said electrodes, respectively, said switch means selectively connecting one of said pair of circuits to said source of energy.

2. An arrangement as defined in claim 1 further including means for momentarily simultaneously connecting both said circuits to said source.

3. An arrangement as defined in claim 1 further including means for simultaneously connecting both said circuits to said source for a period that is at least of a second.

4. An arrangement as defined in claim 1 further including means for simultaneously connecting both said circuits to said source for a period equal to at least onehalf the period of the frequency of the source.

5. An arrangement as defined in claim 1 further including means for simultaneously connecting both said circuits to said source for an interval of time between a half period of the feed voltage and of a second.

6. A switching arrangement as defined in claim 1 further including a second auxiliary tube in shunt with the first mentioned auxiliary tube.

7. A switching arrangement as defined in claim 6 further including a relay in series with at least one of said auxiliary tubes and means connecting said relay to the primary winding of the transformer for disconnecting the primary winding from an energy source when the current through the relay increases by a predetermined amount.

8. A switching arrangement as defined in claim 6 further including a relay in series with both auxiliary tubes and means operative by said relay for disconnecting the primary winding of the transformer from an energy a source of energy source when the current through the relay increases by a predetermined amount.

9. A switching arrangement as defined in claim 6 wherein one of said auxiliary tubes has a higher starting voltage than the other, a relay in series with said tube of higher starting voltage and means operative by said relay for disconnecting the primary winding of the transformer from an energy source when the current through the relay increases by a predetermined amount.

10. An arrangement for switching the secondary winding of a transformer from one circuit to another of a pair of circuits, each circuit containing a plurality of discharge tubes in series and each tube having an ionizable atmosphere comprising means connecting one end of each of said circuits to one end of the secondary winding, an auxiliary tube having an ionizable atmosphere, and switch means for selectively connecting said auxiliary tube in series with one of said pair of circuits and the other end of the secondary winding and for connecting the other of said pair of circuits directly to said other end of the secondary winding.

11. An arrangement for switching the secondary winding of a transformer from one circuit to another of a pair of circuits, each circuit comprising parallel branches havplurality of discharge tubes enclosing an ionizable in series in each branch, comprising a circuit for connecting the branches to one end of the secondary winding, an auxiliary discharge tube having an ionizable atmosphere, and switch means for selectively connecting said auxiliary tube in series with one of said pair of circuits and the other end of the secondary winding and for connecting the other of said pair of circuits directly to said other end of the secondary winding.

12. An arrangement as defined in claim 11 further including a second auxiliary tube in shunt relation with the first mentioned auxiliary tube.

13. An arrangement as defined in claim 11 further including means for selectively operating the circuit breakers in the branches of one of the circuits when the current flowing therein is zero.

14. A switching arrangement for a pair of circuits each containing at least one discharge tube having an ionizable atmosphere and each connected in series with one secondary winding of a transformer having a pair of secsald auxiliary tube being connected in series with both said circuits, and switching means for momentarily selectively connecting said auxiliary tube in series with one of said circuits with respect to a reference point exclusive to the other circuit.

15. A switching arrangement as defined in claim 14 further including a second auxiliary tube in shunt with the first mentioned auxiliary tube.

N 0 references cited.

JOHN W. HUCKERT, Primary Examiner. R. F. POLISSACK, Assistant Examiner.

Claims

1. AN ARRANGEMENT FOR SWITCHING A SOURCE OF ENERGY FROM ONE CIRCUIT TO ANOTHER OF A PAIR OF CURCUITS, EACH CIRCUIT CONTAINING AT LEAST ONE MAIN DISCHARGE TUBE HAVING AN IONIZABLE ATMOSPHERE, COMPRISING AN AUXILIARY TUBE HAVING A PAIR OF ELECTRODES IN AN IONIZABLE ATMOSPHERE, SAID AUXILIARY TUBE BEING CONNECTED INSERIES WITH THE MAIN TUBES, AND SWITCH MEANS HAVING A PAIR OF TERMINALS, ONE TERMINAL BEING CONNECTED TO ONE OF SAID ELECTRODES, RESPECTIVELY, SAID SWITCH MEANS SELECTIVELY CONNECTING ONE OF SAID PAIR OF CIRCUITS TO SAID SOURCE OF ENERGY.