US3728578A - High output operating apparatus for a fluorescent lamp - Google Patents

High output operating apparatus for a fluorescent lamp Download PDF

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Publication number
US3728578A
US3728578A US00137781A US3728578DA US3728578A US 3728578 A US3728578 A US 3728578A US 00137781 A US00137781 A US 00137781A US 3728578D A US3728578D A US 3728578DA US 3728578 A US3728578 A US 3728578A
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US
United States
Prior art keywords
cathode
lamp
windings
winding
preheating
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Expired - Lifetime
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US00137781A
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English (en)
Inventor
S Nozawa
H Kuroi
M Hatada
S Fukuyama
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Blackwell Electronics Ind Co Ltd
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Blackwell Electronics Ind Co Ltd
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Publication date
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/16—Circuit arrangements in which the lamp is fed by DC or by low-frequency AC, e.g. by 50 cycles/sec AC, or with network frequencies
    • H05B41/18—Circuit arrangements in which the lamp is fed by DC or by low-frequency AC, e.g. by 50 cycles/sec AC, or with network frequencies having a starting switch
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/05—Starting and operating circuit for fluorescent lamp

Definitions

  • a high output operating circuit for a fluorescent lamp includes, in one embodiment, a magnetic circuit formed by confronting E-cores and having a pair of outer legs and a center leg.
  • a pair of lamp current control windings are wound on the outer legs, and a cathode preheating compensation winding and a pair of cathode heating windings are wound on the center leg.
  • the flux from the current control windings are in opposition in the center leg.
  • the compensation winding is connected across the lamp between the cathodes by a glow starter. During preheating, the glow starter is closed, and the flux from the compensation winding superposed in the center leg provides optimum cathode preheating. When the lamp is operating, the glow starter is open, and the opposed flux in the center leg provides optimum cathode heating.
  • a lamp current control winding, a pair of cathode heating windings, and a preheating compensation winding are wound on a common magnetic circuit.
  • a pair of manually operated switches connect the windings in series with the lamp cathodes to provide optimum cathode preheating. During operation, the switches remove the compensation winding from the circuit and connect the cathode heating windings across the cathodes to provide optimum cathode heating.
  • the object of the invention is to provide a high output operating apparatus for glow starting and for manual starting, which can give the highest output by minimizing cathode exhaustion of the fluorescent lamp, which is cheap in cost by being constructed with a simple magnetic circuit, and which, moreover, has superior utility by minimizing the noise of the ballast.
  • the high output lighting circuits of the invention supply, through a low internal impedance cathode heating winding, a cathode heating voltage which is shifted by 90 degrees against lamp current and adjusted to an optimum heating voltage corresponding to the case which provides the greatest reduction of cathode exhaustion by the cathode heating effect, thus providing a substantially greater reduction of the cathode exhaustion than that provided by ordinary equi-high impedance, ordinary high impedance cathode heating circuits which are equivalent to high equi-impedance circuits in their function, or bi-pin shorted high output circuits.
  • the invention is also concerned with the control of the cathode exhaustion during the starting of the lamp.
  • the temperature should rapidly fully rise so as to bring about full cathode emission
  • the amplitude of the starting pulse should not be excessive.
  • any excessive kick voltage induced at the time when the glow starter opens is absorbed and suppressed because of the fact that the cathode preheating circuit forms a secondary closed circuit.
  • An optimum preheating voltage should be given to the cathode; otherwise, larger preheating current from the voltage source will flow due to the fact that the resistance of the cathode filament is shorted by the cathode arc before the temperature of the cathode has fully risen.
  • the preheating current compensation winding is connected in additive polarity; thus, any excessive kick voltage is suppressed, and the optimum preheating current is supplied by the preheating current compensation winding.
  • the magnetic circuit which is simply constructed by confronting two E-cores, has the benefit of providing a ballast having minimum noise, because in this kind of high output operating circuit, the capacity of the ballast reaches two or three times the rated lamp current. Moreover, this is useful for keeping the cost lower, bringing about a practical advantage.
  • a useful high output operating system can be provided, which can keep the cathode exhaustion at a minimum.
  • the invention contemplates the provision of a common magnetic circuit and lamp current control means, cathode heating windings, and a cathode preheating compensating winding wound thereon.
  • Switch means connects the compensating winding across the lamp for preheating and disconnects the compensating winding during operation of the lamp.
  • the windings are so wound and connected that during preheating, optimum preheating voltage is supplied to the cathodes, and, during operation of the lamp, optimum heating voltage is supplied to the cathodes, and the cathode heating voltage is shifted ninety degrees from the lamp current.
  • the magnetic circuit is formed by a pair of confronting E-cores and has a pair of outer legs and a center leg.
  • a pair of lamp current control windings are wound on the outer legs and provide flux in opposition in the center leg.
  • the compensating winding and the cathode heating windings are wound on the center leg, and a glow starter connects the compensation winding across the lamp for preheating, at which time the winding contributes to the flux in the center leg.
  • the glow starter opens and the compensating winding is removed from the circuit.
  • a lamp current control winding, a cathode preheating compensation winding, and a pair of cathode heating windings wound in opposition to the control and compensation windings are connected by a pair of manual switches in series with the lamp cathodes for preheating. During lamp operation, the switches disconnect the compensating winding and connect the cathode heating windings across the respective cathodes.
  • FIG. 1 is a circuit diagram showing an embodiment of the invention
  • FIG. 2 shows the structure of magnetic circuit in the above circuit
  • FIG. 3 is a circuit diagram showing another embodiment of the invention.
  • FIG. I The circuit diagram shown in FIG. I is an embodiment of the invention applied in a glow starter system.
  • a magnetic circuit formed by confronting two E-cores E and E has a lamp current control winding divided into two windings N and N on left and right legs 1 and 2, respectively, both cathode heating windings N and N for heating the cathodes and a compensation winding N for preheating the cathodes being wound on a center leg 3,
  • one end of the control winding N is connected with one end a of a cathode filament 5 of a fluorescent lamp 4
  • one end of the control winding N is connected with one end of a cathode filament 6 of the lamp 4.
  • each cathode filament that is, between a and c
  • compensation winding N and a glow starter switch means 7 are connected in series.
  • Two pairs of ends a, b and c, d are connected to both ends of cathodes 5 and 6, respectively
  • An A.C. source S is provided between the other ends of windings N, and N.
  • a flux F (shown in full line in FIG. 2) generated by control winding N is opposed to a flux F (shown in dotted line in FIG. 2) generated by control winding N at center leg 3 and is additive to it at two legs 1 and 2.
  • the flux interlinking with cathode heating windings N and N has been set to a desired value by selecting a suitable combination of the number of turns of control windings N,, N and the size of the core (which depends upon the gaps formed between the confronting portions of each leg of the cores, the sectional area of each magnetic path, the length of the path and so on)
  • the reason why the flux'density in center leg 3 is lowered by passing the fluxes in opposite directions is that, otherwise, in such a system as the cathodes are heated by means of control windings N N on a common magnetic path, during the time the lamp is operating, a sufficient flux is hardly obtained in the course of preheating and, also, an input current in the preheating period becomes too large, bringing about remarkably poor economy.
  • the invention provides sufficient cathode preheating voltage and cathode heating voltage by means of an economical structure of the magnetic circuit, both the cathode heating voltage and the preheating voltage being adjusted to a desired optimum value.
  • the cathode heating voltages induced in the cathode heating windings N and N are shifted by about 90 against the lamp current; and because a reluctance of the center leg is chosen to be low as compared to reluctances of the right and the left legs, which is contrary to the structure of leakage path in so-called leakage transformers, a series inductance formed equivalently at the heating winding becomes very small, forming a low internal impedance circuit and thus exhibiting good branching characteristics.
  • FIG. 3 The circuit shown in FIG. 3 is another embodiment of the invention applied to a type of manual start.
  • a lamp current control winding 8, windings 9 and 10 for heating the cathodes, and an adjusting winding 11 for preheating current are all wound around the same magnetic path 12.
  • Switches 13 and 14, have ganged switch arms and 21, are provided for determining the connections of windings 8, 9, 10, and 11 to the cathodes 16 and 17 of fluorescent lamp 15.
  • switch arms 20 and 21 are connected to first fixed contacts 22 and 23 to connect an end of winding 9 to cathode 17 and an end of winding 10 to cathode 16, respectively.
  • Switch arms 20 and 21 may be moved to a second position into contact with second fixed contacts 24 and 25 to connect the opposite ends of winding 11 to cathodes 17 and 16, respectively.
  • the lamp current control winding 8 is connected at one end thereof to a source 18, the other end thereof being connected to cathode heating winding 9 and fixed contact 22 of switch 13.
  • Two ends of cathode 17 are connected via switch 13 to both ends of cathode heating winding 9, while two ends moved to the second position in contact with fixed contacts 24 and 25, respectively, current will flow from source 18 through winding 8, winding 9, cathode 17, switch 13, winding 11, switch 14, cathode l6, winding 10, and switch 19 back to source 18.
  • Each winding 8, 9, 11, 10 will be connected in series in the circuit as a single choke coil, and thus as ordinary preheating circuit of switch start type will be formed.
  • switch arms 20 and 21 of switches 13 and 14 are switched into the first position in contact with fixed contacts 22 and 23, respectively.
  • a current will then flow from source 18 through winding 8, winding 9 and cathode 17 in parallel, fluorescent lamp 15, cathode 16 and winding 10 in parallel, and switch 19 back to source 18, providing current for an operating circuit.
  • cathode heating windings 9 and 10 are so wound as to function in opposition to lamp current control winding 8.
  • the inductances of windings 9 and 10 reduce the inductance of the winding 8 for controlling the lamp current, and therefore the number of turns of winding 8 required to maintain a predetermined lamp current is remarkably increased as compared to the case wherein the cathode heating windings are connected additively.
  • the requisite that the cathode heating voltage should be shifted correctly by in relation to the lamp current is thereby satisfied to realize a balance of cathode spots.
  • each winding is inserted in series as a single choke coil during the preheating period and the switch start method is adopted, lamp starting is reliable.
  • the cathode heating windings are connected subtractively in relation to the lamp current control winding and can balance the cathode spots while heating the cathodes. Therefore, a higher output or longer life can be obtained than that obtained in the equal impedance system of the prior art. All the four windings can be wound around the same magnetic path, and thus a cheaper lighting apparatus than that of the equal impedance system can be provided, which is suitable in particular to a high output lighting apparatus for a fluorescent desk lamp.
  • a high output operating apparatus for a fluorescent lamp of the cathode heating type and having a cathode at each end comprising a magnetic circuit having a first and second outer leg and a center leg, two lamp current control windings wound, respectively, around said outer legs, a compensation winding for cathode preheating and two cathode heating windings wound around the center leg of the magnetic circuit, said cathode heating windings having low internal impedance, means for supplying current to said lamp control windings and said compensation winding before said lamp is operating, the flux in said center leg being superposed to induce current in said two cathode heating .windings to provide optimum preheating of the cathodes and excessive kick voltage being controlled by absorption of kick energy by secondary closed circuits formed with said low internal impedance cathode heating windings, and for supplying current to said lamp control windings and said lamp while disconnecting said compensation winding during the time the lamp is operating to form flux in the center leg by opposing the fluxes of
  • a high output operating apparatus for a fluorescent lamp of the cathode heating type having a cathode at each end comprising two cathode heating windings having low internal impedance, a lamp current control winding, and a cathode preheating compensation winding wound around the same magnetic path, and switch means for connecting each winding in series, when the lamp is preheated prior to operation of said lamp, and, when the lamp is operating, to exclude the cathode preheating compensation winding from the circuit, means for supplying current to said series connected windings with said cathode preheating compensation winding being connected withadditive polarity to the lamp current control winding to provide optimum preheating current and to control excessive kick voltage and for supplying current to said circuit with said cathode preheating compensation winding excluded, said circuit then including said lamp current in opposition to said lamp control winding to provide optimum cathode heating voltage shifted degrees against lamp current in said low internal impedance cathode heating windings, whereby cathode
  • said lamp current control means comprises a lamp current control winding, and said switch means, when in said first state, connecting all of said windings in series with said cathodes.
  • said switch means comprises a pair of manually operated switches, and wherein said switches, when in said second state, connect said cathode heating windings across said cathodes, respectively,

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  • Circuit Arrangements For Discharge Lamps (AREA)
US00137781A 1970-11-30 1971-04-27 High output operating apparatus for a fluorescent lamp Expired - Lifetime US3728578A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45105644A JPS50636B1 (enrdf_load_stackoverflow) 1970-11-30 1970-11-30

Publications (1)

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US3728578A true US3728578A (en) 1973-04-17

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US00137781A Expired - Lifetime US3728578A (en) 1970-11-30 1971-04-27 High output operating apparatus for a fluorescent lamp

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US (1) US3728578A (enrdf_load_stackoverflow)
JP (1) JPS50636B1 (enrdf_load_stackoverflow)
DE (1) DE2138451C3 (enrdf_load_stackoverflow)
FR (1) FR2115780A5 (enrdf_load_stackoverflow)
GB (1) GB1357746A (enrdf_load_stackoverflow)
IT (1) IT939141B (enrdf_load_stackoverflow)
SE (1) SE7414338L (enrdf_load_stackoverflow)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9200211D0 (en) * 1992-01-07 1992-02-26 Warner Ian R Energy efficient unit

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB525133A (en) * 1939-02-14 1940-08-22 Gen Electric Co Ltd Improvements in circuit arrangements for operating electric discharge devices
US2802143A (en) * 1955-09-07 1957-08-06 Keiji Tanaka Starting device for a preheating type fluorescent lamp
US3047772A (en) * 1957-01-14 1962-07-31 Keiji Tanaka High output starting device for a preheating type fluorescent lamp
US3114076A (en) * 1961-08-15 1963-12-10 Kobayashi Takizo Fluorescent lamp circuit and starting means therefor
US3211952A (en) * 1965-10-12 Fluorescent lamp operating circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3211952A (en) * 1965-10-12 Fluorescent lamp operating circuit
GB525133A (en) * 1939-02-14 1940-08-22 Gen Electric Co Ltd Improvements in circuit arrangements for operating electric discharge devices
US2802143A (en) * 1955-09-07 1957-08-06 Keiji Tanaka Starting device for a preheating type fluorescent lamp
US3047772A (en) * 1957-01-14 1962-07-31 Keiji Tanaka High output starting device for a preheating type fluorescent lamp
US3114076A (en) * 1961-08-15 1963-12-10 Kobayashi Takizo Fluorescent lamp circuit and starting means therefor

Also Published As

Publication number Publication date
IT939141B (it) 1973-02-10
GB1357746A (en) 1974-06-26
DE2138451A1 (de) 1972-06-15
SE7414338L (enrdf_load_stackoverflow) 1974-11-14
FR2115780A5 (enrdf_load_stackoverflow) 1972-07-07
DE2138451C3 (de) 1975-10-30
DE2138451B2 (de) 1975-03-13
JPS50636B1 (enrdf_load_stackoverflow) 1975-01-10

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