US3555352A - Gas discharge lamp operating system - Google Patents

Gas discharge lamp operating system Download PDF

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Publication number
US3555352A
US3555352A US673837A US3555352DA US3555352A US 3555352 A US3555352 A US 3555352A US 673837 A US673837 A US 673837A US 3555352D A US3555352D A US 3555352DA US 3555352 A US3555352 A US 3555352A
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Prior art keywords
lamp
current
harmonic
electric system
resonance
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Expired - Lifetime
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US673837A
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English (en)
Inventor
Maksymilian A Michalski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bank of America Illinois
Prudential Insurance Company of America
First National Bank of Minneapolis
Wells Fargo Bank Minnesota NA
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Berkey Photo Inc
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Assigned to PAKO CORPORATION reassignment PAKO CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BERKEY PHOTO, INC.
Assigned to NORWEST BANK MINNEAPOLIS, FORMERLY NORTHWESTERN NATIONAL BANK OF MINNEAPOLIS, A NATIONAL BANKING ASSOCIATION, CONTINENTAL ILLINOIS NATINAL BANK AND TRUST COMPANY OF CHICAGO, A NATIONAL BANKING ASSOCIATION, FIRST NATIONAL BANK OF MINNEAPOLIS, A NATIONAL BANKING ASSOCIATION, PRUDENTIAL INSURANCE COMPANY OF AMERICA, A NJ CORP. reassignment NORWEST BANK MINNEAPOLIS, FORMERLY NORTHWESTERN NATIONAL BANK OF MINNEAPOLIS, A NATIONAL BANKING ASSOCIATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: PAKO CORPORATION, 6300 OLSON MEMORIAL HWY., MINNEAPOLIS, MN 55440 A DE CORP.
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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
    • H05B41/20—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 no starting switch
    • H05B41/23—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 no starting switch for lamps not having an auxiliary starting electrode
    • H05B41/232—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 no starting switch for lamps not having an auxiliary starting electrode for low-pressure lamps

Definitions

  • the present invention relates to gas discharge lamps, and more particularly to an electric system' for operating gas discharge lamps containing mercury or mercury and other metal additives in the form of halides.
  • ballasts connected in series with capacitances to provide regulated supplies for the discharge lamps.
  • these types of ballast have been designed to limit the current to an amount at most lessthan 150 percent of the operating value for the discharge lamps even under starting conditions which are practically short circuit conditions.
  • a gas filled mercury lamp presents a very low impedance upon being ignited because the mercury is in liquid form and thus the resistance of the lamp depends only upon the type of the gas filling and upon the physical dimensions of the discharge lamps.
  • the gas pressure and impedance increase until a steady operating state is reached.
  • the warmup period of the lamp is quite long and several minutes may pass before the lamp light output is 100 percent.
  • this limitation is a serious drawback.
  • the warmup time of the lamp results in long exposure times which, of course, impede production and increase operating costs.
  • the present invention aims to overcome the foregoing difficulties by providing an electrical system for operating gas discharge lamps in which faster warmup time isachieved.
  • the electric system includes a saturable inductance in series with a capacitor and a discharge lamp.
  • the system components are so selected that the system operates at or near third harmonic resonance during the warmup period, the operation gradually shifting to supply current at input source frequency resonance or near resonance during operation.
  • the system is advantageous in that a starting current of at least double normal current is provided during the warmup period which thereby lessens the time required for the lamp to reach operating temperature. ln addition, the operation at or near resonance acts as a stabilizing effect in maintaining practically constant light output and lamp voltage although there are variations in the input voltage.
  • FIG. 1 is a schematic drawing of the circuit of an electric system in accordance with the invention.
  • FIG. 2 is a perspective drawing of an autotransformer showing shunts between the primary and secondary windings.
  • FIG. 3 shows a series of curves illustrating the performance characteristics of the electric system.
  • FIG. 4 is a regulation curve of the electric system.
  • FIGS. 5 and 6 show theoretical waveforms including the fundamental the third harmonic and the resultant waveforms with the third harmonic component in phase (FIG. 5) and leading by 90 (H6. 6).
  • FIGS. 7 through 9 show theoretical waveforms of line voltage, lamp current, and lamp voltage of systems with a capacitor in series with the discharge lamp (FIG. 7), a resistor in series with the discharge lamp (FIG. 8), and an inductor in series with the discharge lamp (FIG. 9).
  • H6 shows waveforms of the autotransformer voltage, the capacitor voltage, and the lamp voltage at the start of the warmup period for the discharge lamp.
  • FIG. it shows waveforms according to H0. 5 but taken after the warmup period has passed and during normal operatron.
  • H6. 11 a schematic circuit 10 of an electric system in accordance with the invention.
  • An alternating current source Preferably of the order of 200 to 250 volts, is connected to the input terminals 11 and 12.
  • An autotransforcmer 14' is provided'with a primary winding and a secondary winding 16.
  • the secondary winding 116 is connected through a main capacitor 17 in series with secondary winding 19 of a starting trari forrher ZQwhich has its primary winding 21 supplied by a cofnv ti on ii'l starting circuit 22.
  • the secondary winding 19 is es connc ct'ed to a discharge lamp 2 1 having terminals 25 and J being connected to terminal 25 while the term nal 16 is connected to the primary 15 of the autotransform 1 41 I
  • the starting circuit 22 may be of any conve'nti onal type or may be as shown in US. Pat. No. 3,309,566 issued Mar. I4, 1967 to the applicant herein. In the operation of the starting circuit a series of high frequency pulses are produced in the starting circuit 22 and stepped up in voltage through the transformer 20 and superimposed on the alternating current supplied to the lamp 24.
  • the starting pulse transformer 20 is of the ferrite core type, thereby being suitable for, passage of the high frequency pulses but presenting very low impedance to the passage of operating current.
  • a bypass capacitor 27 is connected across the series connected secondary winding 19 of the starting transformer 20 and the lamp 24 to complete the circuit for the high frequency pulses of the starting circuit.
  • the capacitor 27 is of low capacity and passes very little purrent at the operating
  • the autotransformer 14 is preferably of the type shown in FIG. 2 incorporating a core 30 which may comprise, a threelegged laminated core structure built up of El-shaped laminations and bar laminations with adjacent laminations being reversed to break the joints in the usual manne,r.
  • the primary winding 15 and the secondary winding 16 are wound on the center leg 31.
  • a pair of high reluctance magnetic shunts32 and 33 are interposed between the center legend the outer legs of the core 30 between the primary andsecondary windings 15 and 16. Air gaps are provided at,the ends of .the shunts, thereby making a loose coupling between the .primary and the secondary coils on the core.
  • an autotransformer is preferred for use in the electric system in accordance with the invention
  • alternative constructions might utilize a transformer having a loosely coupled secondary or a saturable inductance connected in series with the terminal voltage without any step up voltage means.
  • a transformer having a loosely coupled secondary or a saturable inductance connected in series with the terminal voltage without any step up voltage means Such a saturable reactor would provide high leakage reactance and act in a manner similar as the autotransformer described here.
  • the autotransformer is considered the preferable construction because of lower material and construction cost.
  • the terminals 111 and 12 are connected to a source of alternating current preferably of standard 60 cycle frequency with a voltage of the order of 250 volts.
  • the starting circuit is energized usually from the same alternating current source. Upon ignition of the discharge tube 24 by the starting circuit a current of at least twice normal operating current flows through the discharge lamp 24 thereby bringing it up to operating temperature at a rapid rate.
  • the circuit constants are so selected and proportioned relative to the circuit constants of the discharge lamp 24 that the circuit resonates at or close to a harmonic frequency immediately upon ignition of the discharge lamp 24.
  • the circuit constants are preferably arranged so that the operation is at the third harmonic.
  • the circuit constants automatically adjust so that operation of the electric system gradually shifts to close to resonance at the supply frequency which is preferably 60 cycles, the leakage reactancc of the autotransformer cooperating with the capacitor t7 so that a regulating action is provided compensating to a large degree for variations in the voltage of the supply frequency.
  • the discharge lamp characteristics are viewed.
  • the lamp resistance is practically linear in the operating range.
  • the inductance of the secondary circuit of the autotransformer M and the capacitor l7 are selected with values such as to provide a near resonant condition for the operating conamount which may cause damage to the seals of the lamp.
  • the operation is at or near resonance at harmonic frequency, thereby the effective reduced capacitance of the capacitor 17 passes a higher than normal current.
  • the inherent reactance of the autotransformer would tend to theoretically increase at the increased harmonic frequency.
  • the saturable effect of the greater than normal current during starting reduces the effective value of the inductance reactance under the harmonic condition.
  • the circuit constants may be more expeditiously arrived at by experiment rather than by calculation.
  • the normal operating current is about I amperes and the operating resistance is about 20 ohms.
  • the inrush current should be limited to a maximum of 30 smperes in order that no damage be caused to the electrode seals.
  • the resistance of the 2,000 watt lamp is only a fraction of an ohm. Therefore, the total impedsnce of the autotransformer secondary and of the capacitor 17 must be of the order of about 8 ohms.
  • a core 30 was constructed in which the center leg 31 was 2% square inches in cross-sectional area with the outer legs 1% square inches in crosssectional area.
  • the shunts 32 and 33 were 7/ l6 by l 3/32 inches in cross section, the end air gaps being about one-sixteenth of an inch.
  • the shunts 32 and 33 were positioned between'the primary winding and the secondary winding 16.
  • the primary winding 15 was wound with 304 turns of number 16. wire while the secondary 16 was wound with 176 turns of number 13 wire.
  • lamp current curve 40 shows a starting current of about double normal. continuing generally at this magnitude 15 for about seconds, whereupon there is a rapid decrease in the current to normal operating value of about 10 amperes. The decrease in the current is related somewhat to the increase in the impedance of the lamp as it warms up to operating temperature and pressure.
  • Lamp wattage curve 41 initially is about 500 watts and generally follows the pattern of the current curve 40 and increases to slightly over 2,000 watts during operation.
  • Curve 42 shows a voltage drop across the lamp of about 10 volts for approximately IO seconds, the lamp voltage then increasing rapidly for about the next seconds to reach its operating 30 wattage curve 41, the power factor rising rapidly during the 20 to 40 second period of operation.
  • curve 48 The regulation of the lamp is shown by curve 48 (FIG. 4). It will be noted that the light variation is only 20 percent for an 50 input voltage variation of 50 volts, or a .4 percent change in the light output for each 1 percent voltage change.
  • Table I shows that the i i TABLE I The, Input Lamp Primary Capac- Trans- Lamp, Lamp, Light in Input, Volt, PI. m current current coll itor, former, volts watts foot watts ampere leading current volts volts candles inpu I. 24. 4. 410 410 20 500 30 900 6, 500 138 B. 0 23. 5 4. 95 415 410 20 500 48 900 5, 900 155 23. 5 23. 3 4. 95 413 412 20 500 900 5, 900 155 22. 2 Q. 0 4. 8 MB 410 35 600 850 1, 000 5, 600 178 12. 6 12. 5 4. 25 360 410 1, 620 1, 420 1, 800 3, 200 563 10.9 10.8 3.
  • Table II sets out the respective values of the impedances of the secondary inductance and of the capacitor under starting and operating conditions. These impedance values were obcapacitor voltage and the transformer voltage are identical in value at start therefore providing evidence of a resonant con- 75 dition.
  • the capacitor voltage is lower by approximately percent than the transformer voltage indicating that the circuit is not quite in resonance which is advantageous because if the circuit were in resonance unstable conditions would occur. During warmup the importance of stable operation is not so important.
  • the lamp current is 24 amperes dropping off to 10.7 amperes for operation.
  • the starting current is 2.24 times operating current.
  • the circuit may be readily adjusted to provide a larger starting current by increasing the capacitance and decreasing the inductance.
  • the gain in warmup time is appreciable when compared with standard available ballast. Under the same conditions, a gain of 3 to 4 times can be achieved. For example a 2,000-watt metal halide lamp reaches 75 percent of its output in 30 seconds and 100 percent output in 45 seconds (curve 41). The same lamp operated with a standard ballast reaches 75 percent output in 90 seconds and 100 percent output in 2 /2 to 3 minutes. Also, comparable savings in material costs in copper and laminations are in the range of 30 to 40 percent. Power factor obtained with the new type is .8 while the conventional ballast types usually operate at .6-power factor.
  • FIGS. 5 and 6 there are shown theoretical waveforms copied from textbooks for comparison with the actual wavefonns taken during operation of a system in accordance with the invention and illustrating the effect on the shape of a waveform with harmonic components.
  • Waveform 50 of FIG. 5 is the resultant of a fundamental 51 and a third harmonic 52 in which the third harmonic is in phase with the fundamental.
  • the waveform 54 is the resultant of the fundamental waveform 55 and a third harmonic waveform 56 but in which the third harmonic waveform 56 leads the fundamental waveform 55 by 90.
  • Waveform 59 of FIG. 7 shows a supply voltage waveform.
  • Waveform 60 shows the discharge lamp or tube voltage while waveform 61 shows the waveform of the lamp current.
  • the waveforms 59 to 61 illustrate operation with a capacitor series connected with the discharge lamp.
  • Waveform 62 of FIG. 8 shows the supply voltage and waveform 64 the discharge lamp or tube voltage, while waveform 65 is of the lamp current.
  • the waveforms 62 to 65 illustrate operation with a resistor series connected with the discharge lamp.
  • waveform 66 shows the supply voltage waveform.
  • Waveform 67 shows the discharge lamp or tube voltage while waveform 69 shows the lamp current.
  • the waveforms 66 to 69 illustrate operation with an inductor series connected with the discharge lamp.
  • Waveform 70 was taken across the autotransformer 14 including the series connected primary l5 and the secondary l6.
  • Waveform 7] shows the voltage across the main capacitor 17 and waveform 72 shows the voltage across the discharge lamp 24.
  • the autotransformer voltage waveform includes a relatively small harmonic effect, while the capacitor voltage waveform 7 I and the discharge lamp voltage waveform 72 clearly show leading third harmonic effects.
  • the third harmonic effect is apparently caused by the partial saturation of the autotransformer due to its regulating action.
  • Waveform 74 corresponds to waveform 70 of FIG. 10 and shows the voltage across the series connected primary I5 and secondary 16 of the autotransformer 14.
  • the capacitor voltage is shown as waveform 75 and the lamp voltage as waveform 76.
  • the absence of harmonic components in the capacitor waveform 75 and the decreased harmonic effect in the discharge lamp waveform 76 will be noted. Also note the increased harmonic effect in the autotransformer voltage waveform 74.
  • waveforms 79 and 80 show respectively the starting and operating currents in the circuit.
  • an electric system which advantageously operates at or near resonance during the warmup period thereby supplying the discharge lamp with increases current to bring the lamp quickly to operating temperature. Thereafter the system operates close to resonance thereby providing a regulating action so that the light output of the discharge lamp remains practically constant during the usual line voltage variations.
  • An electric system for use with an alternating current source comprising a saturable transformer, a capacitor, and a gas discharge lamp connected in a series circuit, the lamp when initially ignited having low impedance, the lamp impedance increasing as the lamp is warmed up to operating temperature, the respective values of the impedances of the saturable transformer, the capacitor, and the lamp being such that a harmonic component is generated in said series circuit upon ignition of said lamp, said circuit operating at least close to resonance at said harmonic frequency during the warmup period of said lamp, the circuit constants being such that operation of said circuit gradually shifts to at least close to resonance at supply frequency as said lamp reaches operating temperature, specifically the saturable transformer having constants such that it has a partially saturated primary during the starting phase using the resonance of the third harmonic current, the constants of the saturable transformer such that its primary gradually unsaturates as the lamp warms up using supply frequency resonance, whereby during the operation at close to harmonic frequency the effective reduced capacitive reactance passes a higher than normal current to flow through said lamp for
  • said harmonic frequency is the third
  • said saturable inductance is an auto transformer with a high reluctance magnetic shunt between the primary and secondary coils, and the voltage drops across said saturable inductance and saidcapacitor are practically equal during said harmonic operation.
  • said harmonic frequency is the third
  • said saturable inductance is an autotransformer with a high reluctance magnetic shunt between the primary and secondary coils
  • the r.m.s. value of the lamp current at said operation upon ignition of said lamp is at least twice the r.m.s. value of the normal operating current.
  • said harmonic frequency is the third said saturable inductance is an autotransformer with a high reluctance magnetic shunt between the primary and secondary coils
  • the voltage drop across said saturable inductance is at least 75 percent of the voltage drop across said capacitor at said operation at least close to supply frequency resonance
  • the r.m.s. value of the lamp current at said operation upon ignition of said lamp is at least twice the r.m.s. value of the normal operating current.

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US673837A 1967-10-09 1967-10-09 Gas discharge lamp operating system Expired - Lifetime US3555352A (en)

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DE (1) DE1802149B2 (de)
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GB (1) GB1236604A (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3125261A1 (de) * 1980-07-07 1982-06-16 Nuarc Co Steuerschaltung fuer eine hochleistungs-entladungslampe
US4339692A (en) * 1980-11-18 1982-07-13 The Nuarc Company, Inc. Power supply for HID lamp
US4399391A (en) * 1981-06-10 1983-08-16 General Electric Company Circuit for starting and operating fluorescent lamps
US4608523A (en) * 1984-01-16 1986-08-26 Nilssen Ole K Phase correction for series-resonant ballasts
US5013974A (en) * 1987-08-24 1991-05-07 Nilssen Ole K Electronic ballast with improved lamp current crest factor
US5021714A (en) * 1990-05-10 1991-06-04 Valmont Industries, Inc. Circuit for starting and operating fluorescent lamps
US5506479A (en) * 1991-08-23 1996-04-09 Robert Bosch Gmbh Device for operating a gas-discharge lamp
US6100652A (en) * 1998-11-12 2000-08-08 Osram Sylvania Inc. Ballast with starting circuit for high-intensity discharge lamps
US20060164023A1 (en) * 2003-07-23 2006-07-27 Patent-Treuhand-Gesellschaft Gur Elektrisch Gluhlampen Mbh Circuit for operating high-pressure discharge lamps
US20090251061A1 (en) * 2005-11-02 2009-10-08 Osram Gesellschaft Mit Beschraenkter Haftung Apparatus for Operating at Least One Discharge Lamp

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2120470A (en) * 1982-04-27 1983-11-30 Emi Plc Thorn Improvements in or relating to discharge lamp circuits

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2333499A (en) * 1940-10-30 1943-11-02 William A Warren Starting and operating circuit for hot cathode gaseous discharge lamps
US2334568A (en) * 1942-01-22 1943-11-16 Gen Electric Apparatus for starting and controlling electrical discharge devices
US2470460A (en) * 1948-06-05 1949-05-17 Hanovia Chemical & Mfg Co Wattage controlling system
US2482894A (en) * 1947-10-07 1949-09-27 Hanovia Chemical & Mfg Co Operating system for vapor arc lamps
US2487092A (en) * 1947-07-23 1949-11-08 Lester F Bird Flickerless operation of electric lighting elements
US2588858A (en) * 1947-10-07 1952-03-11 Lehmann Frantisek Circuit arrangement for discharge tubes, particularly glow discharge tubes
US2773217A (en) * 1952-01-29 1956-12-04 Gen Motors Corp Fluorescent lamp system
US2858481A (en) * 1954-06-02 1958-10-28 Engelhard Ind Inc Operating circuit for compact type arc lamps

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2333499A (en) * 1940-10-30 1943-11-02 William A Warren Starting and operating circuit for hot cathode gaseous discharge lamps
US2334568A (en) * 1942-01-22 1943-11-16 Gen Electric Apparatus for starting and controlling electrical discharge devices
US2487092A (en) * 1947-07-23 1949-11-08 Lester F Bird Flickerless operation of electric lighting elements
US2482894A (en) * 1947-10-07 1949-09-27 Hanovia Chemical & Mfg Co Operating system for vapor arc lamps
US2588858A (en) * 1947-10-07 1952-03-11 Lehmann Frantisek Circuit arrangement for discharge tubes, particularly glow discharge tubes
US2470460A (en) * 1948-06-05 1949-05-17 Hanovia Chemical & Mfg Co Wattage controlling system
US2773217A (en) * 1952-01-29 1956-12-04 Gen Motors Corp Fluorescent lamp system
US2858481A (en) * 1954-06-02 1958-10-28 Engelhard Ind Inc Operating circuit for compact type arc lamps

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3125261A1 (de) * 1980-07-07 1982-06-16 Nuarc Co Steuerschaltung fuer eine hochleistungs-entladungslampe
US4339692A (en) * 1980-11-18 1982-07-13 The Nuarc Company, Inc. Power supply for HID lamp
US4399391A (en) * 1981-06-10 1983-08-16 General Electric Company Circuit for starting and operating fluorescent lamps
US4608523A (en) * 1984-01-16 1986-08-26 Nilssen Ole K Phase correction for series-resonant ballasts
US5013974A (en) * 1987-08-24 1991-05-07 Nilssen Ole K Electronic ballast with improved lamp current crest factor
US5021714A (en) * 1990-05-10 1991-06-04 Valmont Industries, Inc. Circuit for starting and operating fluorescent lamps
US5506479A (en) * 1991-08-23 1996-04-09 Robert Bosch Gmbh Device for operating a gas-discharge lamp
US6100652A (en) * 1998-11-12 2000-08-08 Osram Sylvania Inc. Ballast with starting circuit for high-intensity discharge lamps
US20060164023A1 (en) * 2003-07-23 2006-07-27 Patent-Treuhand-Gesellschaft Gur Elektrisch Gluhlampen Mbh Circuit for operating high-pressure discharge lamps
US7221103B2 (en) * 2003-07-23 2007-05-22 Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh Circuit for operating high-pressure discharge lamps
US20090251061A1 (en) * 2005-11-02 2009-10-08 Osram Gesellschaft Mit Beschraenkter Haftung Apparatus for Operating at Least One Discharge Lamp

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Publication number Publication date
FR1588297A (de) 1970-04-10
DE1802149B2 (de) 1979-04-05
DE1802149A1 (de) 1969-06-04
GB1236604A (en) 1971-06-23

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