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US2910623A - Ballast construction - Google Patents

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Publication number
US2910623A
US2910623A US591711A US59171156A US2910623A US 2910623 A US2910623 A US 2910623A US 591711 A US591711 A US 591711A US 59171156 A US59171156 A US 59171156A US 2910623 A US2910623 A US 2910623A
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lamp
capacitor
ballast
mercury vapor
harmonic
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US591711A
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Joseph C Yaeger
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McGraw Edison Co
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McGraw Edison Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/08—High-leakage transformers or inductances
    • H01F38/10—Ballasts, e.g. for discharge lamps

Definitions

  • ballasts are unitswhichcomprise in effect a transformer and condensers associated therewith, in. which the. transformers are ⁇ usually so. constructed that a magnetic shuntV or magnetic leak. isprovided.V
  • the crest ⁇ factor ⁇ isi lower.
  • the lower crest factor occurs whenY the peak. or crestcurrent is relatively low whereas, on ⁇ the other hand, the peak or crest current for a2 high crest factor is, relatively high. Consequently, for a low crest factor there is less chance of the boiling off or driving off of the" low electron ainity: material with the deleterious effects hereinabove noted.
  • ballasts of the above type it is the usual practice to provide two resonant circuits assoeiatedwith theLsecondary ⁇ or output portion of the transformer of ther constant wattage ballast. It is the customary practice to so arrange the circuits that what may be called the first resonant circuit, resonates at the third harmonic and is employed to secure a high striking or starting Voltage for the mercury vapor lamp. In the customary practice, what may be called the second or operating circuit is so arranged that it resonates at the fundamental frequency.
  • This invention is designed to provide a constant Wattage ballast which has a low value for the third harmonic current during the operating period of the lamp, that is to say, while the lamp is hot and is operating in its normal capacity. As shown hereinabove, this reduces the amount of low electron affinity material that is driven off from an electrode of the lamp since the peak value ice 2 of the: alternatingcurrent during operating conditions is lower due to the reduction of the third harmonic.
  • Figure-2 is afragmentanyview ofa portion of: ⁇ theibal-iA last showing primarily. ⁇ themagnetic core and windings;
  • the magnetic shunts are ⁇ diagrammatically shown in Figure l.
  • the shunts maybe formed as shown in- Figure 2 ⁇ and-indicated at ⁇ 3 by suitably stamping out' the ⁇ core 2..
  • The; primary is ⁇ shownA at 4- and ⁇ thesecondary at Si.
  • TheV rouge-yf may have.
  • taps if desired, onmay be formed 'as-shown in Figr ure ⁇ l ⁇ of: two windings ⁇ which may be ⁇ connectedV either in shunt. or in parallel, for la120-l 30 volts1 or 220-260 volts.
  • the secondary supplies a.- single mercury vapor lamp ⁇ indicated, by the ⁇ reference character 6. ⁇ Inf ⁇ the system. oft mercury vapor lighting for which this. ⁇ ballast is made each lamp. is. provided ⁇ with ⁇ its ⁇ own individual ballast'. ⁇
  • a relatively large; capacitor indicated bythe reference character, 7 is placed in series with the secondary 5 and is shunted: by, ahigh resistance leak. of theforder of several, hundredthousand ohms..
  • a capacitor 9 of relatively low capacitance, as compared with the capacitor 7, is connected directly across the output leads from the secondary '5.
  • the capacitor 7 is connected on the outer side or delivery side between the lamp 6 and the rest of the secondary circuit. This is a very important feature of the invention. It is connected in such a manner as shown in Figure l that the lamp 6 directly bridges the capacitor 9.
  • the capacitor 9 When the lamp is not in operation, that is to say, when the lamp is cold, the capacitor 9 is effective and forms a portion of a resonant circuit including the capacitor 9, the capacitor 7, and the secondary 5. This circuit resonates for the third harmonic. However, when the lamp 6 is in operation, it provides a shorting or bridging circuit directly across the capacitor 9 thereby greatly lessening the effect of the capacitor 9 or else entirely suppressing the action of the capacitor 9 so that the resonant circuit hereinabove mentioned for the third harmonic no longer exists, or if it operates at all in resonance, its effect is tremendously reduced.
  • the lamp when the lamp has struck and is operating, it forms a portion of a resonant circuit including the lamp 6, the capacitor 7 and the secondary 5.
  • This circuit resonates at the fundamental frequency.
  • the third harmonic is practically, if not entirely, suppressed as explained hereinabove.
  • the input and output terminals of the constant wattage ballast are indicated by the reference characters 11, I11 and 10, respectively. It is to be understood that the magnetic shunts 3 operate in the usual manner to limit the current by providing a leakage path for the magnetic ux.
  • the crest factor is greatly reduced during operating conditions of the lamp since the third harmonic is materially reduced if not completely suppressed.
  • the lamp 6 tends to short out the capacitor 9 and consequently to suppress the'third harmonic which causes thes high peaks in the alternating current wave.
  • This suppression of the third harmonic results in the low crest factor.v I.It is essential that the capacitor 9 be connected at a point beyond the capacitor 7. That is to say on the side of the capacitor 7 opposite the secondary 5, as explained hereinabove.
  • a mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury vapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to the input terminals and having a secondary, a relatively large capacitor connected in series between an output terminal and one side of said secondary, the other side of said secondary being connected to the other output terminal, a relatively small capacitor connected across the output terminals between theV output terminals and the first mentioned capacitor and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said second mentioned capacitor, the lamp, the relatively large capacitor, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacil tor, the relatively large capacitor, and the secondary forming a circuit resonating at an odd harmonic frequencyi 2.
  • a mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury vapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to Ithe input terminals and having a secondary, said transformer having magnetic shunting means provided with an air gap and located between said primary and said secondary, relatively large capacitor means connected in series between an output terminal and one side of said secondary, 'the other side of said secondary being connected to the other output terminal, a relatively small capacitor connected across the output terminals between the output terminals and said capacitor means and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said relatively small capacitor, the lamp, the relatively large capacitor means, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacitor, the relatively large capacitor means, and the secondary forming a circuit resonating at an odd harmonic frequency.
  • a mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury lvapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to the input terminals and having a secondary, a relatively large capacitor means connected in series between the output terminals and said secondary, a relatively small capacitor connected across the output terminals between the output terminals and said capacitor means and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said relatively small capacitor, the lamp, the relatively large capacitor means, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacitor, the relatively large capacitor means, and the secondary forming a circuit resonating at an odd harmonic frequency.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)

Description

C 27, 19 J. c. YAEGER 2,910,623
' BALLAST CONSTRUCTION Filed June l5, 1956 n k," l JH N l 1 l l l l 8 l l l l I IQ. z I 3 f| l 6 l "I l g l 5 j C 9 i A 1 l lo l l JNVENTOR. JOSEPH Cl` Yat-:GER
Avvaanev United States Patent BALLAST CONSTRUCTION Joseph C..Yaeger, Milwaukee, Wis., .assignor. to McGraw- Edison Company, a corporation. of Delawaren Application June 115, 1956t,Serial'-No. 591,711-l 3 Claims. (Cl.` 3159-241) This invention relates to` a. constant wattage ballast construction whichis particularly usefulinmercury vapor lighting systems where av separate ballastisrprovided; for each lamp.
In mercury vapor lighting systems where` the mercury vapor lamps are placed inshunt, `it isacustomary practice to provide each lamp` with an individual constant wattage ballast. These ballasts are unitswhichcomprise in effect a transformer and condensers associated therewith, in. which the. transformers are` usually so. constructed that a magnetic shuntV or magnetic leak. isprovided.V
It has been found that when` the.` lamp, current crest factor,. which is the` ratio of the peak current to,V the Rit/LS.,y is high that the total. output of.y lightl for thelife ofthe lamp is lower than where the crest factor is` lower. While the theory isnot entirely clear it` is believed that this is due to the factthat the low. electron affinity material with which the` one or more electrodes` ofithe mer.- cury vapor lamp are provided seems to boil out or to be driven oiffor thev highf current` peaksW-hereithere. is `a highcrest factor. This material collects or condenseslon the inner Walls of thev quartz or hardflglass tube of the mercury vapor lamp, and lowers the lumen. output of the lamp after a relatively short periodA of use4 so that during the entire life period` of the lamp itsytotall light output is less than where the crest` factor` isi lower. The lower crest factor occurs whenY the peak. or crestcurrent is relatively low whereas, on `the other hand, the peak or crest current for a2 high crest factor is, relatively high. Consequently, for a low crest factor there is less chance of the boiling off or driving off of the" low electron ainity: material with the deleterious effects hereinabove noted.
In ballasts of the above type, it is the usual practice to provide two resonant circuits assoeiatedwith theLsecondary` or output portion of the transformer of ther constant wattage ballast. It is the customary practice to so arrange the circuits that what may be called the first resonant circuit, resonates at the third harmonic and is employed to secure a high striking or starting Voltage for the mercury vapor lamp. In the customary practice, what may be called the second or operating circuit is so arranged that it resonates at the fundamental frequency.
It has been found through extensive experimentation that in the usual forms of ballasts hereinabove discussed, the third harmonic is still present in an undesirably high value during the normal operation of the lamp and con,
sequently the lamp current crest factor is high, thus limiting or lowering the entire output during the total life period of the lamp. i
This invention is designed to provide a constant Wattage ballast which has a low value for the third harmonic current during the operating period of the lamp, that is to say, while the lamp is hot and is operating in its normal capacity. As shown hereinabove, this reduces the amount of low electron affinity material that is driven off from an electrode of the lamp since the peak value ice 2 of the: alternatingcurrent during operating conditions is lower due to the reduction of the third harmonic.
It has been found further that where the crest factor isihigh, thatthe'warmmp-period of theV lamp is-` increased overaA that required where the crestv factor` is lower. In certain. instances thelamp neven f-ully warms up andfconsequently fails `to function properly, Where the orest=factor1` is high. It is, therefore, a further object to provide.` a ballast which is` soconstructed that the warm-ups period of the..v mercury vapor lamp `is reduced;
Aspecific object of` this invention is tofprovide aibald lasticonstruction in.y which one of=` the elements of theres.d onantI circuit'. which resonates:1 atY the third harmonicv is; in effectA shortediout or. partially shortediout duringi the.` op.- eratingperiodofthelamp, so thatY the value` of. thethird.` harmonic current, when the lamp is. in.` operation,.is.greatly reduced while` at' the` sametime the outputacircuit is arrangedtto resonate at` 60 cycles.`
Anembodimentf of the invention is shown in the accompanying drawings in which:
liigure.I l1 isia diagrammatic` view of the` constant` wattage4 ballast.
Figure-2 is afragmentanyview ofa portion of:` theibal-iA last showing primarily.` themagnetic core and windings;
Itis: customary to: constructthe ballast as a unitary structure. with-` all of:V the` component parts carried` in a housing or casing. This diagrammatically shown` in Figure lby the, dotted line,V indicated by the reference character 1. y
The. transformer consists-1 of the main core 2= of larni` nated material provided. with. magnetic shunts= 3. AS1` a matter of fact, the transformer is not made` of an unbroken sheet for each lamination as indicated in Figure 2, but is made of the usual strips or punchings.which,r are built up intoi the; final' forinshown. in Figure 2. The magnetic shunts are` diagrammatically shown in Figure l. The shunts maybe formed as shown in-Figure 2` and-indicated at` 3 by suitably stamping out' the` core 2.. The; primary is` shownA at 4- and` thesecondary at Si. TheV primar-yf may have. taps if desired, onmay be formed 'as-shown in Figr ure` l` of: two windings` which may be` connectedV either in shunt. or in parallel, for la120-l=30 volts1 or 220-260 volts. The secondary supplies a.- single mercury vapor lamp` indicated, by the` reference character 6.` Inf` the system. oft mercury vapor lighting for which this.` ballast is made each lamp. is. provided` with` its` own individual ballast'.`
A relatively large; capacitor indicated bythe reference character, 7 is placed in series with the secondary 5 and is shunted: by, ahigh resistance leak. of theforder of several, hundredthousand ohms.. A capacitor 9 of relatively low capacitance, as compared with the capacitor 7, is connected directly across the output leads from the secondary '5. lIt is to be noted particularly that the capacitor 7 is connected on the outer side or delivery side between the lamp 6 and the rest of the secondary circuit. This is a very important feature of the invention. It is connected in such a manner as shown in Figure l that the lamp 6 directly bridges the capacitor 9.
When the lamp is not in operation, that is to say, when the lamp is cold, the capacitor 9 is effective and forms a portion of a resonant circuit including the capacitor 9, the capacitor 7, and the secondary 5. This circuit resonates for the third harmonic. However, when the lamp 6 is in operation, it provides a shorting or bridging circuit directly across the capacitor 9 thereby greatly lessening the effect of the capacitor 9 or else entirely suppressing the action of the capacitor 9 so that the resonant circuit hereinabove mentioned for the third harmonic no longer exists, or if it operates at all in resonance, its effect is tremendously reduced.
On the other hand, when the lamp has struck and is operating, it forms a portion of a resonant circuit including the lamp 6, the capacitor 7 and the secondary 5. This circuit resonates at the fundamental frequency. During the normal operation of the lamp the third harmonic is practically, if not entirely, suppressed as explained hereinabove.
' The input and output terminals of the constant wattage ballast are indicated by the reference characters 11, I11 and 10, respectively. It is to be understood that the magnetic shunts 3 operate in the usual manner to limit the current by providing a leakage path for the magnetic ux.
It will be readily seen that the crest factor is greatly reduced during operating conditions of the lamp since the third harmonic is materially reduced if not completely suppressed. In other words, the lamp 6 tends to short out the capacitor 9 and consequently to suppress the'third harmonic which causes thes high peaks in the alternating current wave. This suppression of the third harmonic results in the low crest factor.v I.It is essential that the capacitor 9 be connected at a point beyond the capacitor 7. That is to say on the side of the capacitor 7 opposite the secondary 5, as explained hereinabove.
It will be seen that a relatively simple construction is provided by this invention in which the ballast produces the minimum of the third harmonic, and consequently greatly reduces the value of the crest factor.
From actual tests it has been found that the warm-up period of the lamp is materially reduced by reducing the crest factor as hereinabove set forth. 1 Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.
I claim:
1. A mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury vapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to the input terminals and having a secondary, a relatively large capacitor connected in series between an output terminal and one side of said secondary, the other side of said secondary being connected to the other output terminal, a relatively small capacitor connected across the output terminals between theV output terminals and the first mentioned capacitor and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said second mentioned capacitor, the lamp, the relatively large capacitor, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacil tor, the relatively large capacitor, and the secondary forming a circuit resonating at an odd harmonic frequencyi 2. A mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury vapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to Ithe input terminals and having a secondary, said transformer having magnetic shunting means provided with an air gap and located between said primary and said secondary, relatively large capacitor means connected in series between an output terminal and one side of said secondary, 'the other side of said secondary being connected to the other output terminal, a relatively small capacitor connected across the output terminals between the output terminals and said capacitor means and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said relatively small capacitor, the lamp, the relatively large capacitor means, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacitor, the relatively large capacitor means, and the secondary forming a circuit resonating at an odd harmonic frequency.
3. A mercury vapor alternating current lighting system for striking and operating mercury vapor lamps comprising a ballast having input and output terminals, a mercury lvapor lamp connected across the output terminals, said ballast comprising a transformer having a primary connected to the input terminals and having a secondary, a relatively large capacitor means connected in series between the output terminals and said secondary, a relatively small capacitor connected across the output terminals between the output terminals and said capacitor means and being directly bridged by said mercury vapor lamp, whereby when said mercury vapor lamp is lighted it forms a short circuit directly bridging said relatively small capacitor, the lamp, the relatively large capacitor means, and the secondary forming the major part of a circuit resonating at the fundamental frequency, and the relatively small capacitor, the relatively large capacitor means, and the secondary forming a circuit resonating at an odd harmonic frequency.
References Cited in the file of this patent UNITED STATES PATENTS 2,355,360 Boucher et al Aug. 8, 1944 2,429,162 Keiser Oct. 14, 1947 2,439,976 Keiser et al Apr. 20, 1948 2,496,981 Boucher Feb. 7, 1950 2,858,479 Sola Oct. 28, 1958
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1200435B (en) * 1964-02-21 1965-09-09 Patra Patent Treuhand Operating equipment for electric high-pressure discharge lamps with gradual brightness control
US3629650A (en) * 1968-11-21 1971-12-21 Patrick And Drew Ltd Method and apparatus for operating a gas discharge tube
US3771068A (en) * 1973-01-02 1973-11-06 Gte Sylvania Inc Constant wattage autotransformer ballast for high pressure sodium lamp
DE3715162A1 (en) * 1987-05-07 1988-11-17 Bosch Gmbh Robert CIRCUIT ARRANGEMENT FOR OPERATING A GAS DISCHARGE LAMP ON A DC POWER SOURCE

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2355360A (en) * 1942-09-14 1944-08-08 Boucher Inv S Ltd Fluorescent tube system and apparatus
US2429162A (en) * 1943-01-18 1947-10-14 Boucher And Keiser Company Starting and operating of fluorescent lamps
US2439976A (en) * 1942-08-05 1948-04-20 Boucher And Keiser Company Fluorescent lamp circuit
US2496981A (en) * 1944-04-26 1950-02-07 Boucher And Keiser Company Negative reactance lamp system
US2858479A (en) * 1956-05-21 1958-10-28 Basic Products Corp Alternating current power supply apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2439976A (en) * 1942-08-05 1948-04-20 Boucher And Keiser Company Fluorescent lamp circuit
US2355360A (en) * 1942-09-14 1944-08-08 Boucher Inv S Ltd Fluorescent tube system and apparatus
US2429162A (en) * 1943-01-18 1947-10-14 Boucher And Keiser Company Starting and operating of fluorescent lamps
US2496981A (en) * 1944-04-26 1950-02-07 Boucher And Keiser Company Negative reactance lamp system
US2858479A (en) * 1956-05-21 1958-10-28 Basic Products Corp Alternating current power supply apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1200435B (en) * 1964-02-21 1965-09-09 Patra Patent Treuhand Operating equipment for electric high-pressure discharge lamps with gradual brightness control
US3629650A (en) * 1968-11-21 1971-12-21 Patrick And Drew Ltd Method and apparatus for operating a gas discharge tube
US3771068A (en) * 1973-01-02 1973-11-06 Gte Sylvania Inc Constant wattage autotransformer ballast for high pressure sodium lamp
DE3715162A1 (en) * 1987-05-07 1988-11-17 Bosch Gmbh Robert CIRCUIT ARRANGEMENT FOR OPERATING A GAS DISCHARGE LAMP ON A DC POWER SOURCE

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