US3038103A - Circuit controller - Google Patents

Description

June 5, 1962 T. J. GRECU CIRCUIT CONTROLLER Filed Aug. 31. 1959 w mm H m B4 w.

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JNVENTOR: THO MAS J. GRECU United States Patent 1 3,038,103 CIRCUIT CQNTROLLER ThomasJ. Grecu, 1821 W. North Ave, Chicago, Ill. Filed Aug. 31, 1959, Ser. No. 836,959 9 Claims. (Cl. 315-241) This invention relates to a circuit controller, and more particularly to a control arrangement automatically operable to cyclically shift a circuit from one set of conditions to another. The invention is applicable to both high voltage and high current circuits and has utility, for example, as an animating device for fluorescent and neontype signs.

Signs of the type considered are used extensively for advertising, and for many years there has been a trend toward animation of such signs in order to attract attention thereto. In general, the animation consists of cyclically interrupting the energizing circuit for the sign so that it flashes on and off repetitively. One of the major difliculties in on-off arrangements of this type is that for a substantial portion of the time, the sign is not illuminated and the message thereof is not being delivered. Additionally, sign interrupters or flashers of the usual type create interference with radio, television and similar appliances and materially reduce the longevity of fluorescent signs. Further, in high current circuits, such interrupters create heat factors which affect the stability of the interruption cycle.

An object of the present invention is to provide a circuit control device especially useful in connection with such signs and which obviates the deficiencies of conventional interrupters or flashers. Another object of the invention is in the provision of a control device automatically operable to cyclically deliver two levels of electric power at a stable rate, neither of which levels approximates a zero value, whereby an electric sign controlled by the device has no completely off condition.

Still another object is that of providing a control device useful in connection wtih high voltage or high current circuits, and which is operative to define two levels of electric power cyclically and repetitively delivered to a utilization device such as an electric neon or fluorescent sign, and which is effective to flash such sign cyclically between bright and dim conditions whereby the sign has no unilluminated time. Yet another object is in the provision of a control device which will permit two levels of electrical energy to be conducted on the high voltage circuit of the flashing rapid-start fluorescent ballast, and such two levels of electric energy are conducted alternately at a stable cycle rate such that the brightness of a sign illuminated by fluorescent lamps changes to a degree measurably perceptible to the eye without reducing the illumination to a level where the message disappears.

A further object is that of providing a circuit control device of the character described which will conduct high electric current energy values without creating intrinsic or extrinsic heat factors which would affect the stability of the cycle of operation. Still a further object is that of providing a control device of the type described, which is operative to open the electric circuit spontaneously if an electric surge occurs which is greater than the recommended power values irrespective of whether such surge occurs from either the primary source of power or from the sign or other utilization device being electrically controlled.

Yet a further object is to provide a control device which is silent in its operation, which creates no radio or television interference by suppressing or obviating electrical frequencies'which would otherwise cause the same, which is easily installed and requires substantially no maintenance, which is small and compact and susceptible to being completely contained within a hermetically sealed fidddflli Patented June 5, 1962 enclosure, and which effectively extends the longevity 6f fluorescent-type signs. Additional objects and advantages of the invention will become apparent as the specification develops.

Embodiments of the invention are illustrated in the accompanying drawings, in which:

FIGURE 1 is a schematic circuit diagram of a control device embodying the invention and which is especially useful in high voltage circuits; and FIGURE 2 is a schematic circuit diagram of a modified control device especially useful in high current circuits.

The circuit illustrated in FIGURE 1 is denoted generally with the numeral 10, and is adapted to be connected at points 11 and 12 by conductors 13 and 14 to a source of electric power which may be volts at 60 cycles. The primary winding 15 of a ballast transformer is connected across the conductors 13 and 14. The ballast transformer is of the auto type, and one side of the secondary winding 16 is connected to a conductor 1'7 while the other side thereof is connected at point 18 to the control device which is denoted generally as 19. The control device is also connected to one side of the primary winding 15, as shown at point 20. A plurality of fluorescent lamps arranged in series are connected between the conductors 13 and 17, and such fluorescent lampswhich are respectively designated with the numerals 2.1, 2.2 and 23-may be, for example, of the rapidstart type having a rating of 800 milliamps and 590 volts open circuit.

The device 19 comprises a plurality of parallel circuit units connected between the conductor 14 or point 2%) therealong and a conductor 24 which is electrically coextensive with the point 18. That is to say, the device 19 and more particularly the circuit units thereof are connected between one end of the primary winding 15 of the transformer and one end of the secondary winding 16 thereof. The first circuit unit 25 includes a pair of resistors 26 and 27 having a capacitor 28 connected therebetween. The second unit 29 comprises a serially connected inductance 3t and capacitor 31. The unit 32 includes a resistance 33 serially connected to a resistor 34; and the circuit unit 35 comprises a heat-sensitive switch 36 having normally open contacts 37 and 38.

The heat-responsive switch 36 may comprise a therrnosensitive bimetallic element operative to close the contacts 37 and 38 when subjected to a temperature in excess of a predetermined value. The resistance 33 is a heater element for the bimetal switch 37, and may be a Nichrome wire wound about the switch 37 in insulated relation therewith. The inductance 30 is a peaking coil, and the value of the capacitor 28 is substantially larger than the value of the capacitor 31. The units 25, 2.9 and 3-2 are in parallel with each other, and such units and the summation thereof are in parallel with the unit 35 or, more particularly, the thermo-responsive switch 36 which comprises the same.

The light intensity produced by the lamps 21 through 23 is proportional to the amount of current flowing therethrough in a ratio such that the higher the current value, the brighter will be the light intensity of each of the lamps. Thus, when the current-limiting impedance provided by the device 19 is increased, the amount of current flowing through the lamps 21 through 23 is decreased along with the light intensity thereof. The ballast transformer comprising the windings 15 and 16 is effective to produce a voltage of sufficient magnitude to cause ignition of the lamps 21 through 23; and after ignition has taken place, the high leakage reactance of the transformer output circuit limits the flow of current through the lamps to the rated value thereof so as to prevent the lamps from being burned out.

In operation of the circuit, and assuming the condition illustrated in which the switch contacts 37 and 38 are open, connection of the conductors 13 and 14 to a source of electric power establishes a voltage across the lamps 21 through 23 to cause ignition thereof, and current flows from the point 12 through the conductor 14, resistance heating element 33, resistor 34 through the transformer winding 16, lamps 21 through 23, and back to the point 11 through conductor 13. The capacitors 28 and 31 charge during this period of operation, and the bimetallic switch 36 is heated by the current flow through the resistance heating element 33. Ultimately, such heating of the switch 36 deflects the same and the contact 37 carried thereby until such contact engages the contact 38 and establishes an electric connection therebetween.

This effectively establishes a substantially resistance-free or short circuit between the points 20 and 18 of the transformer windings, and the value of the current flowing through the lamps 21 through 23 increases, as does the intensity of the illumination defined by these lights. This later operating condition persists until the temperature of the bimetallic switch 36 has decreased to a degree such that the anti-flex thereof opens the contacts 37 and 38, at which time a current flow is again initiated through the resistance or heating element 33 and resistor 34; and because of the impedance afforded thereby, the value of the current flowing through the lamps decreases, as does the light intensity thereof.

When the contacts 37 and 38 are open and during the closing time thereof, the capacitors 28 and 31 become charged; and when the contacts 37 and 38 are closed, the capacitors will discharge into the circuit. Capacitor 28 is connected in series with resistors 26 and 27, and as a consequence the rate of discharge of the capacitor 28 is retarded or is momentarily delayed. However, capacitor 31 which is connected in series with the peaking coil 31) discharges instantaneously and thereby attenuates both high and low electrical frequencies, and provides a surge of current effective to penetrate any oxide formation on the engaging surfaces of the contacts 37 and 38. This prevents arcing of the contacts as they move from the open to the closed position thereof. Such contacts have closed before capacitor 28 discharges, and thus arcing of the contacts is prevented at the discharge of capacitor 28.

When the contacts 37 and 33 are closed and a relatively high current is flowing through the circuit, an instantaneous change in the value of the current flowing in the circuit will be resisted by the transformer winding 16, as when the contacts 37 and 38 are opened, and this resistance to change affords time for such contacts to initiate the opening thereof without the occurrence of arcing. Following such initial opening of the contacts, and as the transformer winding 16 desaturates, the circuit units 25 and 29 will absorb the immediate increase in the voltage and current. That is to say, abruptly terminating the electric power to an auto transformer results in the transformer resisting a change in the value of the current flowing therethrough. However, the value of the voltage will change immediately, which then results in a shift from normal in the voltage-current phase relation. This shift in the present circuit causes no arcing of the contacts as they move from an intially open to their completely open position because of the function of the units 25 and 29.

The modified circuit illustrated in FIGURE 2 is designated generally with the numeral 40, and is adapted to be connected at points 41 and 42 by conductors 43 and 44 to a source of electric power which may be 115 volts at 60 cycles. Connected in the line 44 is a primary winding 45 of a neon transformer 46 having a secondary winding 47 connected across a neon sign or other lamp device 48. Interposed between one side of the primary winding 45 and the line 43 is the control device which is designated generally with the numeral 49. For convenience, the points of connection of the control device '49 are denoted with the numerals 50 and 51.

The control device 49 comprises a plurality of circuit units arranged in parallel. One such unit comprises a capacitor 52 connected between the points and 51. A circuit unit 53 is also connected between these same two points, and includes peaking coils 54 and 55, an inductance 55 and a resistance element 57, all connected in series. In parallel with the inductance 56 and resistance 57 are a pair of normally open contacts 58 provided by a heatsensitive switch 59. The heat-responsive switch 59 may comprise a thermo-sensitive bimetallic element operative to close the contacts 58 when subjected to a temperature in excess of a predetermined value. The resistance 57 is actually a heater element for the switch 59, and may be a Nichrome wire wound about the switch in insulated relation therewith.

The light intensity produced by the neon device 48 is proportional to the amount of current flowing therethrough in a relationship such that the higher the current value, the brighter will be the intensity of the device. Thus, when the current limiting impedance provided by the control device 49 is increased, the amount of current flowing through the neon sign 48 is decreased and, consequently, so is the light intensity thereof. The neon transformer is effective to produce a voltage of sufficient magnitude to cause ingnition of the neon device 48.

In operation of the circuit, and assuming the condition thereof as shown in FIGURE 2 with the con-tacts 58 open, power applied across the points 41 and 42 will effect a current flow therebetween through the primary winding 45 of the transformer 46. The voltage appearing across the primary winding of the transformer is limited at this time to a first or lower voltage by the circuit elements 54 through 57 which are in series with the transformer winding, and therefore only a portion of the voltage applied between the points 41 and 42 appears across the primary winding 45. Since current flows through the resistance or heater element 57, the thermo responsive switch 59 begins to heat; and when the proper temperature is reached the contacts 58 close, thereby shunting the heater 57 and inductance 56. The voltage across the primary winding 45 of the transformer is increased to a second or higher value since the voltage drop previously appearing across the inductance 56 and heater 57 is omitted. Consequently, the voltage induced in the secondary winding 47 of the transformer is increased, as is the current flow through the neon device 48, and therefore the light intensity of the device is increased.

Arcing of the contacts 58 upon closing thereof is prevented by the peaking coils 54 and 55 which tend to re sist a sudden change in the value of the current flowing in the circuit. During closing of the contacts 58, the capacitor 52 discharges instantaneously, and thereby attenuates both high and low electrical frequencies and provides a surge of current effective to penetrate any oxide formation on the engaging surfaces of the contacts 58. This action also tends to prevent arcing of the contacts as they move from the open to the closed position thereof. Since no current flows through the heater 57 when the contacts are closed, the heat-sensitive switch 59 cools and anti-flexes to open the contacts, thereby reinserting the elements 56 and 57 in the circuit, and the operation described is cyclically repeated.

When the switch cools and the contacts 58 are opened, the series reactance of the circuit is increased, and this tends to cause an instantaneous high voltage to be induced across the contacts. Ordinarily, such induced voltage would cause arcing and generation of RR interference, but in the present circuit, capacitor 52 is effectively connected across the contacts and will absorb such high voltage by allowing an instantaneous high current to flow therethrough. Such charging of the capacitor prevents arcing of the contacts during the opening thereof.

The inductance 56 and coils 54 and 55 define a balanced circuit which obviates the development of undue heat,

and therefore the thermo-sensitive switch is not influenced by heat radiation or conduction from these elements and the cyclic operation of the switch remains stable. The capacitor has a suflleient voltage rating as to permit the same to be completely air-sealed, and thus heat developed thereby does not adversely influence the cycle period of the switch. Further, the surface areas of the contacts 58 are quite large, and are preferably formed of silver or cadmium oxide silver which are of low electrical resistance so that high electrical energy values are accommodated thereby with the development of extrinsic heat factors which would disturb the normal cycle of openation of the switch. Therefore, the heater 57 is the only major heat-developing element in the circuit, and thus the cyclic operation of the switch is related only thereto and remains stable even over extended periods of operation. The switch 59 is characterized by a low modulus of resistivity and then is relatively free from the influence of high current conduction and the accumulated wattage of the associated circuit. This is advantageous for extrinsic heat factors will accentuate a high modulus of resistivity, and bimetallic switches are often brought into flexion when they act as conductors and when the electrical energy is high, which results in drift or variation from a predetermined cyclic period of operation. The structure is compact and permits complete sealing which protects the same from the elements as well as from tampering.

While in the foregoing specification embodiments of the invention are described in considerable detail for purposes of making a complete disclosure thereof, it will be apparent to those skilled in the art that numerous changes may be made in such details without departing from the spirit and principles of the invention.

I claim:

1. In a control circuit a load device including means for varying the amount of electrical energy supplied to said load device, a source of power for supplying said load device, said control circuit being connected in series with said load device and said means comprising circuit units connected in parallel with each other, one of said parallel connected circuit units including a capacitor for storing electrical energy when said load device is supplied with energy at a lower level, said capacitor releasing its stored energy when said load device is supplied with energy at a higher level, a second of said parallel connected circuit units having a load component therein for consuming electrical energy when said load device is supplied with energy at said lower level, said load component being rendered inoperative to consume electrical energy when said lead device is supplied with energy at a higher level, said load component including a switch operable by the energy supplied to said lead component, said switch being operable to render said load component inoperative for a predetermined period.

2. The circuit of claim 1 in which said parallel connected circuit units comprises a third parallel connected circuit unit for storing electrical energy when said load device is supplied with energy at a lower level and for releasing its stored energy when said load device is being supplied with energy at a higher level, said third circuit unit including a component retarding the release of stored energy so that such release is subsequent to the change in the load device to the higher energy level, said one parallel connected circuit unit releasing the energy stored therein substantially instantaneously with the load device being supplied with energy at the higher level.

3. In a control circuit, a load device including means for varying the amount of electrical energy supplied to said load device, a source of power for supplying said load device, a transformer energized from said power source automtaically and cyclically varying between lower and higher values the level of energy supplied to said load device, said control circuit being connected in series with said load device and said means comprising circuit units connected in parallel with each other, one of said parallel connected circuit units including a capacitor for storing electrical energy when said load device is supplied with energy at a lower level, said capacitor being adapted to release its stored energy when said load device is supplied with energy at a higher level, a second of said parallel connected circuit units having a load component therein for consuming electrical energy when said load device is supplied with energy at said lower level, said load component being rendered inoperative to consume electrical energy when said load device is supplied with energy at a higher level, said load component including a switch operable by the energy supplied to said load component, said switch being operable to render said load component inoperative for a predetermined period.

4. The control circuit according to claim 3 in which said circuit units comprises a third parallel connected circuit unit for storing electrical energy when said load device is supplied with energy at a lower level and for releasing its stored energy when said load device is being supplied with energy at a higher level, said third circuit unit including a component for retarding the release of stored energy so that such release is subsequent to the change in said load device to the higher energy level, said one parallel connected circuit unit releasing the energy stored therein substantially instantaneously with the load device being supplied with energy at the higher level.

5. The control circuit according to claim 3 in which said load device comprises a gaseous electric lamp.

6. The control circuit according to claim 5 in which said lamp is a neon sign.

7. The control circuit of claim 5 in which said lamp is a fluorescent sign.

8. The control circuit of claim 3 in which a peaking coil is interposed between said switch and the capacitor of said one circuit unit.

9. The control circuit according to claim 3 in which the load component of the second parallel connected circuit unit comprises a resistance heating element and in which said switch is thermo-sensitive and is controlled by said resistance heating element.

References Cited in the file of this patent UNITED STATES PATENTS 2,104,128 Honaman Jan. 4, 1938 2,292,064 Dorgelo Aug. 4, 1942 2,487,734 Seaman Nov. 8, 1949 2,665,068 Williams Jan. 5, 1954 2,718,613 Harris Sept. 20, 1955

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