CA1271515A - Filament winding arrangement in ballast transformer - Google Patents
Filament winding arrangement in ballast transformerInfo
- Publication number
- CA1271515A CA1271515A CA000498342A CA498342A CA1271515A CA 1271515 A CA1271515 A CA 1271515A CA 000498342 A CA000498342 A CA 000498342A CA 498342 A CA498342 A CA 498342A CA 1271515 A CA1271515 A CA 1271515A
- Authority
- CA
- Canada
- Prior art keywords
- winding
- lamps
- primary winding
- cathode
- ballast
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- 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
- H05B41/2325—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 provided with pre-heating electrodes
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- Circuit Arrangements For Discharge Lamps (AREA)
Abstract
Case 2959 FILAMENT WINDING ARRANGEMENT IN
BALLAST TRANSFORMER
ABSTRACT OF THE DISCLOSURE
A ballast apparatus for a lead type, rapid start, fluorescent lamp system is described. In the past the cathode heating windings have been wound on or associated with the primary winding and it was not considered suitable to have a cathode heating winding wound over the secondary winding because of the difficulty of achieving adequate control of the voltage during starting and running. However, by using a ballast design with suitable leakage and magnetizing fluxes and by placing a cathode heating winding on the secondary winding in the region thereof closely adjacent the primary winding, it is possible to obtain suitable voltage output. In lamp systems having three or four lamps operating from a single ballast, it is sometimes desirable to be able to place at least one of the cathode heating windings on a secondary winding.
BALLAST TRANSFORMER
ABSTRACT OF THE DISCLOSURE
A ballast apparatus for a lead type, rapid start, fluorescent lamp system is described. In the past the cathode heating windings have been wound on or associated with the primary winding and it was not considered suitable to have a cathode heating winding wound over the secondary winding because of the difficulty of achieving adequate control of the voltage during starting and running. However, by using a ballast design with suitable leakage and magnetizing fluxes and by placing a cathode heating winding on the secondary winding in the region thereof closely adjacent the primary winding, it is possible to obtain suitable voltage output. In lamp systems having three or four lamps operating from a single ballast, it is sometimes desirable to be able to place at least one of the cathode heating windings on a secondary winding.
Description
~7~5~5 Case 2959 FILAME~T WINDING ARRANG~ENT IN
BALLAST TRANSFORMER
Background of the Invention This invention relates to ballast transformers for use in rapid start fluorescent lighting systems, and in particular it relates to an arrangement for conveniently providing an increased number of lamp filament or cathode heating windings on the ballast.
A rapid start ballast transformer must provide controlled heating current to the cathode or filament heating electrodes at the ends of each fluorescent lamp so that the cathode electrodes are heated by the current to cause ionization during lamp starting and to provide a supply of electrons during normal operation of the lampO In order to prolong the life of the cathode or filament, the operating temperature of the cathode (i.e. the temperature of the hottest spot) should be limited to a predetermined value. This is normally done by limiting the current through the cathode electrode. The current is normally obtained from cathode electrode heating windings in the ballast transfomer. In the past the cathode heating windings have been associated with the primary winding of the ballast transformer, that is, the cathode heating windings have been wound over the lS~S
Case 2959 primary winding, or a suitably tapped portion of the primary winding has been used as a heating winding.
In the past it has not been feasible to have a cathode heating winding associated with a secondary winding in a ballast transformer. This was because of the difficulty of achieving a suitably controlled voltage across a heating winding wound on or tapped on the secondary winding of the ballast transformer. In Canadian Patent No. 805,7~2 issued February 4, lg69 to RI~SLAND, for example, the heating windinys or heater windings G and H appear to be indicated in Figure 6 as being associated with the secondary winding. It appears that this is just for ease of illustration because in the specification on page 5, lines 14 and 15, it is stated that the three heater windings G, H and J are wound on the outside of the primary winding.
A high reactance ballast transformer or ballast apparatus is generally characterized by non-uniform and widely different flux distribution in its core under no load conditions and under normal operating conditions. In a ballast having a leading current in the secondary winding, the flux produced by the ampere-turns in the secondary tends to aid the primary flux which tends to produce a higher output voltage under load than is produced under open circuit conditions. These factors make it difficult to control the heating winding voltage in a heating winding associated with a secondary winding.
Consequently, in the design of a leading current type ballast apparatus for a rapid start fluorescent lamp system, it has been the practice to wind the cathode heating windings over the primary winding or to have a tapped portion of the primary winding as the heating winding.
This presented few problems when a ballast 7~5~S
Case 2959 apparatus was used with one or two fluorescent lamps.
~owever, in order to reduce installation costs and to achieve some energy saving, it is desirable to have a ballast transformer designed for use with a greater numher of lamps, for example with three or four lamps. Canadian application Serial Num~er 498,344 , filed on December 2~, 1985 the name of ZIEMNICKI describes a ballast apparatus for use with four fluorescent lamps where the ballast is in a conventional size case of the type used with a two lamp ballast. As another ~example, Canadian application Serial Number 498, 341 , filed on December 20,1~ herewith in the name of ZIE~ICKI, describes a sys~em whereby four fluorescent lamps operate with a single ballast and have the capability of operation with four lamps or with only two lamps lighted for energy saving. When a ballast apparatus is to supply heating current for the cathode heating electrodes of more than two lamps, it may not be feasible to have all the cathode heating windings wound on the primary winding or tapped off the primary winding.
Summary of the Invention It has been discovered that the voltage obtained from a heating winding wound on the secondary windings adjacent the primary winding is considerably different from the voltage obtained from a heating winding wound of the opposite end of the secondary winding. In a high reactance, lead type ballast, a cathode heatiny winding wound on the secondary winding adjacent the primary will provide a higher no load voltage and a lower indu~ed and operating voltage than a heating winding at locations further from the primary winding. Thus a heating winding in this region of the secondary winding can provide effective voltage control.
Case 2~59 It is therefore an object of the invention to provide a high reactance, lead type ballast apparatus having a cathode heating winding associated with a secondary winding.
It is another object of the invention to provide a high reactance, lead type ballast with a cathode heating winding wound on the secondary windiny adjacent the primary winding.
It is yet another object of the inventioll to provide an improved high reactance, lead type ballast apparatus with up to at least five cathode heating windings.
Accordingly there is provided in a lead type, rapid start, fluorescent lamp system, a ballast apparatus for a plurality of lamps, each lamp having a cathode electrode at each end thereof, comprising, a magnetic core, a primary winding on said core and having first and second ends for connection to an alternating power source, at least one secondary winding on said core, adjacent to and inductively coupled with said primary winding, ballast capacitor means connected to said secondary winding, the series arrangement of said secondary winding and said ballast capacitor means being connected at one end to said primary winding, the other end being provided for connection to said lamps, a plurality of cathode heating windings to provide power to said cathode electrodes, at least one of said cathode heating windings being wound on said secondary winding in the region of said secondary winding having minimum change in flux density between no load conditions and operating conditions, and means for connecting said primary winding to said lamps.
Brief Description of the Drawings The invention will be described with reference to the drawings, in which ~ ~7~
Case 2959 Figure lA is a plan view of a ballast transformer with primary and secondary windings, useful in explaining the invention;
Figure lB is a graph used in conjunction with Figure lA, useful in explaining the invention, Figures 2 and 3 are graphs showing induced voltages on windings shown in Figure lA, under various flux conditions, Figure 4 is a circuit diagram illustrating the ivention;
Figure 5 is a plan view of a ballast transformer in accordance with a form of the invention; and Figure 6 is a simplified circuit diagram of the invention, suitable for use of the ballast transformer of Figure 5.
Description of the Preferred Embodiment Referring to Figure lA, there is shown a ballast 10 having a core 11 with a primary winding 12 and a secondary winding 140 Wound over the secondary winding 14 are two cathode heating windings 15 and 17. These windings were placed in this manner for the purpose of illustrating certain points used in the description of the invention.
Referring now to Figure lB, there is shown a graph of the flux density in the central portion of core 11 plotted against the location along the central core. The solid line 16 represents the center core flux density with the lamps on and the broken line 1~
represents the ceter core flux with the lamps removed, that is in an open circuit condition. Line 20 represents the center line of the primary winding and line 21 represents the center line of the secondary winding. It will be seen that the center core flux density of core 11 does not differ greatly between operating condition and open circuit condition in i5 Case 295g the region of the center core beneath the primary windiny 12. However the change in the center core flux density between operating condition and open circuit condition increases considerably with distance along the central core away from the primary winding region. Thus, the farther away from the primary winding a cathode heating winding is placed, the greater is tlle difficulty in providing a voltage for the cathode heating electrode which can be maintained within desired limits.
Referring now to Figure 2, a graph of induced voltage in windings 15 and 17 (Figure lA) is plotted against flux produced by the primary winding for no load conditions. It will be seen that winding 15 produces a higher voltage than winding 17 and this is suitable for starting. Figure 3 is a graph of induced voltage in windings 15 and 17 (Figure lA) plotted against resultant flux (primary flux plus secondary flux) under operating conditions.
It should be noted that the base for the graphs of Figures 2 and 3 is not the same. In Figure 3 the primary flux is held constant at 100~ and the secondary flux is changed thereby changing resultant flux, to obtain the readings for the graph. It is, however, significant that the winding 15 now provides a lower voltage than winding 17. Thus it becomes clear that the preferred location for a cathode heating winding, associated with the secondary winding, is closely adjacent the primary winding.
This is generally the region where there is minimum change in flux density between no load and operation conditions.
In Figure 4 there is shown an example of a simple fluorescent light system with two lamps in series. Normally~ in such a system, the cathode heatiny windings would be associated with the primary ~7~
Case 2959 as there are only three involved, however, for illustrative purposes, one is shown associated with the secondary winding. Briefly, a ballast comprising an autotransformer 22 has a primary winding portion 23 and a secondary winding portion 24. An operating capacitor or ballast capacitor 25 is connected in series between the primary and secondary windings 23 and 24. The primary winding portion 23 is connected to a supply of electric power over conductors 26 and ~7. This supply may be a conventional 60~Iz, 120 volt al-ternating source. The transformer core is represented by 28. Two fluorescent lamps 30 and 31 have cathode or filament heating electrodes at each end. Lamp 30 has cathode electrodes 30A and 30B, and lamp 31 has cathode electrodes 31A and 31B. The cathode electrodes 30B and 31A are connected in parallel to a cathode heating winding 32 that is wound on primary winding portion 23. The cathode electrode 31B is connected to a tapped portion 33 of primary winding portion 23. Thus the cathode electrodes 30B, 31A and 31B receive power from heating windings associated with primary winding portion 23, to cause them to heat and produce ions within the respective lamps. The cathode electrode 30A is connected to heating winding 34 which is wound over the secondary winding portion 24 in the region adjacent to the primary winding portion 23. The end of secondary winding portion 24 remote from the capacitor 25 is connected to cathode electrode 30A and the conductor 27 is connected to cathode electrode 31B
to provide the voltages across lamps 30 and 31 for starting and running. A starting capacitor 35 is connected in parallel with lamp 30 to provide sequential starting as is ~nown.
Figure 5 shows a ballast having a magnetic core 36 with a central core member 36A and two ~ ,~,7~5~S
Case 2959 side core members 36B and 36C. A primary winding portion 37 and two secondary winding portions 40 and 41 are wound on central core member 36A. Such a ballast would be suitable for the circuit of the lamp system of Figure 6. There are two cathode heating windings 42 and 43 wound on primary windiny portion 37 and there is a cathode heating winding 44 wound on secondary winding portion 40 and a cathode heating winding 45 wound on secondary winding portion 41.
~igure 6 shows a Tluorescent lamp system having four fluorescen~ lamps 46-49. These lamps 46-49 are arranged in ?airs 46,47 and 4~,49 such that both lamps in each pai- o?erate or only one la~p in each pair operates to provide some control over the level of eneryy consumed and the level of illumination. This arrangement is described and claimed in aforementioned copending Canadian appLication Serial l~o. 498,341 . Briefly, each pair of lamps may be operated in a normal series ~0 configuration where both la~ps of the pair are lighted, or in a parallel configuration where only one lamps of the pair is lighted.
Considering the pair of lamps 46 and 47, the lamp 46 has cathode electrGdes 46A and 46B and the lamp 47 has cathode electrodes 47A and 47B. Cathode c c~ ~ c ~
electrode~ 46B and 47B are ~G~e~ in parallel to cathode heatiny winding 42. Cathode electrode 46A is connected to heating electrode winding 44. The heating windings 44 and 45 are shown in Figure 6 at the remote ends of their respective secondary windings. This is for convenience in drawiny. As described, the electrode heating windings 44 and 45 are wound on the secondary winding at the end of the secondary winding adjacent the primary winding.
Tlle cathode heating electrode 47A is connected b~ conductors 52 and 53 to two terminals of 7~S~
_ .
Case 2959 _ g _ a switch 51 which comprises six ganged double pole, single throw, switches. The single terminal side of switch 51 is designated 51Sl to 51S6, and the double terminal side is designated 51Dl to 51D12. Thus conductors 52 and 53 are connected respectively to 51S3 and 51S2. When switch 51 is in the upper position as shown in Figure 6, terminals 51S2 and SlS3 are connected to terminals 51D3 and 51D5 which in turn are connected to conductors 54 and 55. Conductors 54 and 55 are connected to cathode electrode 46A. Thus, with switch 51 in its upper position, cathode electrodes 46A and 47A are connected in parallel.
Also, with switch 51 in its upper position, conductor 26 is connected through switch terminals 51Sl and 51D1 to a conductor 56 which is connected to cathode electrodes 46B and 47B. A
ballasting or operating capacitor 57 connects the remote end of secondary 40 to cathode electrodes 46A
and 47A. In othex words, with switch 51 in its upper position, the lamps 46 and 47 are connected in parallel across secondary windings 40 and capacitor 57. In this configuration, when the power is applied, normally only one lamp of the pair of parallel lamps 46 and 47 will start and run.
The lamps 48 and 49 are connected in a similar manner to secondary winding portion 41 and ballast capacitor 58. The cathode heating windings are, in this case windings 43 and 45. It is believed no further explanation is required.
When switch 51 is in its lower position as seen in Figure 6, the switch terminals 51S2 and 51S3 are connected to terminals 51D4 and 51D6. This connects conductors 52 and 53 to conductors 60 and 61 which are in turn connected to a primary winding portion extension 62. Thus, cathode electrode 47A is now connected to a heating winding portion 62. The Case 2959 conductor 56 is no longer connected through switch 51. It will be seen that lamps 46 and 47 are now connected in series and are across not just the secondary portion 40 (and capacitor 57) but are across the secondary portion 40 and the primary portion 37.
The voltage available for two lamps in series is thus higher. A startiny capacitor 63 is in parallel with lamps 46 to provide sequential starting of the series connected lamps.
The lamps 48 and 49 are connected in a similar manner and operate in a similar manner. It is believed no further explanation is necessary.
In summary, by making the secondary windings, or at least a region of~the secondary winding adjacent the ~i-E~ar~ winding, available ~or placing a cathode electrode heating winding over the secondary winding to provide a suitable controlled heating current for a-e~hodc electrode, there is more room for the winding of heating windings. This is particularly useful where more than three cathode - heating windings are required on one~rapid start leading type ballast.
BALLAST TRANSFORMER
Background of the Invention This invention relates to ballast transformers for use in rapid start fluorescent lighting systems, and in particular it relates to an arrangement for conveniently providing an increased number of lamp filament or cathode heating windings on the ballast.
A rapid start ballast transformer must provide controlled heating current to the cathode or filament heating electrodes at the ends of each fluorescent lamp so that the cathode electrodes are heated by the current to cause ionization during lamp starting and to provide a supply of electrons during normal operation of the lampO In order to prolong the life of the cathode or filament, the operating temperature of the cathode (i.e. the temperature of the hottest spot) should be limited to a predetermined value. This is normally done by limiting the current through the cathode electrode. The current is normally obtained from cathode electrode heating windings in the ballast transfomer. In the past the cathode heating windings have been associated with the primary winding of the ballast transformer, that is, the cathode heating windings have been wound over the lS~S
Case 2959 primary winding, or a suitably tapped portion of the primary winding has been used as a heating winding.
In the past it has not been feasible to have a cathode heating winding associated with a secondary winding in a ballast transformer. This was because of the difficulty of achieving a suitably controlled voltage across a heating winding wound on or tapped on the secondary winding of the ballast transformer. In Canadian Patent No. 805,7~2 issued February 4, lg69 to RI~SLAND, for example, the heating windinys or heater windings G and H appear to be indicated in Figure 6 as being associated with the secondary winding. It appears that this is just for ease of illustration because in the specification on page 5, lines 14 and 15, it is stated that the three heater windings G, H and J are wound on the outside of the primary winding.
A high reactance ballast transformer or ballast apparatus is generally characterized by non-uniform and widely different flux distribution in its core under no load conditions and under normal operating conditions. In a ballast having a leading current in the secondary winding, the flux produced by the ampere-turns in the secondary tends to aid the primary flux which tends to produce a higher output voltage under load than is produced under open circuit conditions. These factors make it difficult to control the heating winding voltage in a heating winding associated with a secondary winding.
Consequently, in the design of a leading current type ballast apparatus for a rapid start fluorescent lamp system, it has been the practice to wind the cathode heating windings over the primary winding or to have a tapped portion of the primary winding as the heating winding.
This presented few problems when a ballast 7~5~S
Case 2959 apparatus was used with one or two fluorescent lamps.
~owever, in order to reduce installation costs and to achieve some energy saving, it is desirable to have a ballast transformer designed for use with a greater numher of lamps, for example with three or four lamps. Canadian application Serial Num~er 498,344 , filed on December 2~, 1985 the name of ZIEMNICKI describes a ballast apparatus for use with four fluorescent lamps where the ballast is in a conventional size case of the type used with a two lamp ballast. As another ~example, Canadian application Serial Number 498, 341 , filed on December 20,1~ herewith in the name of ZIE~ICKI, describes a sys~em whereby four fluorescent lamps operate with a single ballast and have the capability of operation with four lamps or with only two lamps lighted for energy saving. When a ballast apparatus is to supply heating current for the cathode heating electrodes of more than two lamps, it may not be feasible to have all the cathode heating windings wound on the primary winding or tapped off the primary winding.
Summary of the Invention It has been discovered that the voltage obtained from a heating winding wound on the secondary windings adjacent the primary winding is considerably different from the voltage obtained from a heating winding wound of the opposite end of the secondary winding. In a high reactance, lead type ballast, a cathode heatiny winding wound on the secondary winding adjacent the primary will provide a higher no load voltage and a lower indu~ed and operating voltage than a heating winding at locations further from the primary winding. Thus a heating winding in this region of the secondary winding can provide effective voltage control.
Case 2~59 It is therefore an object of the invention to provide a high reactance, lead type ballast apparatus having a cathode heating winding associated with a secondary winding.
It is another object of the invention to provide a high reactance, lead type ballast with a cathode heating winding wound on the secondary windiny adjacent the primary winding.
It is yet another object of the inventioll to provide an improved high reactance, lead type ballast apparatus with up to at least five cathode heating windings.
Accordingly there is provided in a lead type, rapid start, fluorescent lamp system, a ballast apparatus for a plurality of lamps, each lamp having a cathode electrode at each end thereof, comprising, a magnetic core, a primary winding on said core and having first and second ends for connection to an alternating power source, at least one secondary winding on said core, adjacent to and inductively coupled with said primary winding, ballast capacitor means connected to said secondary winding, the series arrangement of said secondary winding and said ballast capacitor means being connected at one end to said primary winding, the other end being provided for connection to said lamps, a plurality of cathode heating windings to provide power to said cathode electrodes, at least one of said cathode heating windings being wound on said secondary winding in the region of said secondary winding having minimum change in flux density between no load conditions and operating conditions, and means for connecting said primary winding to said lamps.
Brief Description of the Drawings The invention will be described with reference to the drawings, in which ~ ~7~
Case 2959 Figure lA is a plan view of a ballast transformer with primary and secondary windings, useful in explaining the invention;
Figure lB is a graph used in conjunction with Figure lA, useful in explaining the invention, Figures 2 and 3 are graphs showing induced voltages on windings shown in Figure lA, under various flux conditions, Figure 4 is a circuit diagram illustrating the ivention;
Figure 5 is a plan view of a ballast transformer in accordance with a form of the invention; and Figure 6 is a simplified circuit diagram of the invention, suitable for use of the ballast transformer of Figure 5.
Description of the Preferred Embodiment Referring to Figure lA, there is shown a ballast 10 having a core 11 with a primary winding 12 and a secondary winding 140 Wound over the secondary winding 14 are two cathode heating windings 15 and 17. These windings were placed in this manner for the purpose of illustrating certain points used in the description of the invention.
Referring now to Figure lB, there is shown a graph of the flux density in the central portion of core 11 plotted against the location along the central core. The solid line 16 represents the center core flux density with the lamps on and the broken line 1~
represents the ceter core flux with the lamps removed, that is in an open circuit condition. Line 20 represents the center line of the primary winding and line 21 represents the center line of the secondary winding. It will be seen that the center core flux density of core 11 does not differ greatly between operating condition and open circuit condition in i5 Case 295g the region of the center core beneath the primary windiny 12. However the change in the center core flux density between operating condition and open circuit condition increases considerably with distance along the central core away from the primary winding region. Thus, the farther away from the primary winding a cathode heating winding is placed, the greater is tlle difficulty in providing a voltage for the cathode heating electrode which can be maintained within desired limits.
Referring now to Figure 2, a graph of induced voltage in windings 15 and 17 (Figure lA) is plotted against flux produced by the primary winding for no load conditions. It will be seen that winding 15 produces a higher voltage than winding 17 and this is suitable for starting. Figure 3 is a graph of induced voltage in windings 15 and 17 (Figure lA) plotted against resultant flux (primary flux plus secondary flux) under operating conditions.
It should be noted that the base for the graphs of Figures 2 and 3 is not the same. In Figure 3 the primary flux is held constant at 100~ and the secondary flux is changed thereby changing resultant flux, to obtain the readings for the graph. It is, however, significant that the winding 15 now provides a lower voltage than winding 17. Thus it becomes clear that the preferred location for a cathode heating winding, associated with the secondary winding, is closely adjacent the primary winding.
This is generally the region where there is minimum change in flux density between no load and operation conditions.
In Figure 4 there is shown an example of a simple fluorescent light system with two lamps in series. Normally~ in such a system, the cathode heatiny windings would be associated with the primary ~7~
Case 2959 as there are only three involved, however, for illustrative purposes, one is shown associated with the secondary winding. Briefly, a ballast comprising an autotransformer 22 has a primary winding portion 23 and a secondary winding portion 24. An operating capacitor or ballast capacitor 25 is connected in series between the primary and secondary windings 23 and 24. The primary winding portion 23 is connected to a supply of electric power over conductors 26 and ~7. This supply may be a conventional 60~Iz, 120 volt al-ternating source. The transformer core is represented by 28. Two fluorescent lamps 30 and 31 have cathode or filament heating electrodes at each end. Lamp 30 has cathode electrodes 30A and 30B, and lamp 31 has cathode electrodes 31A and 31B. The cathode electrodes 30B and 31A are connected in parallel to a cathode heating winding 32 that is wound on primary winding portion 23. The cathode electrode 31B is connected to a tapped portion 33 of primary winding portion 23. Thus the cathode electrodes 30B, 31A and 31B receive power from heating windings associated with primary winding portion 23, to cause them to heat and produce ions within the respective lamps. The cathode electrode 30A is connected to heating winding 34 which is wound over the secondary winding portion 24 in the region adjacent to the primary winding portion 23. The end of secondary winding portion 24 remote from the capacitor 25 is connected to cathode electrode 30A and the conductor 27 is connected to cathode electrode 31B
to provide the voltages across lamps 30 and 31 for starting and running. A starting capacitor 35 is connected in parallel with lamp 30 to provide sequential starting as is ~nown.
Figure 5 shows a ballast having a magnetic core 36 with a central core member 36A and two ~ ,~,7~5~S
Case 2959 side core members 36B and 36C. A primary winding portion 37 and two secondary winding portions 40 and 41 are wound on central core member 36A. Such a ballast would be suitable for the circuit of the lamp system of Figure 6. There are two cathode heating windings 42 and 43 wound on primary windiny portion 37 and there is a cathode heating winding 44 wound on secondary winding portion 40 and a cathode heating winding 45 wound on secondary winding portion 41.
~igure 6 shows a Tluorescent lamp system having four fluorescen~ lamps 46-49. These lamps 46-49 are arranged in ?airs 46,47 and 4~,49 such that both lamps in each pai- o?erate or only one la~p in each pair operates to provide some control over the level of eneryy consumed and the level of illumination. This arrangement is described and claimed in aforementioned copending Canadian appLication Serial l~o. 498,341 . Briefly, each pair of lamps may be operated in a normal series ~0 configuration where both la~ps of the pair are lighted, or in a parallel configuration where only one lamps of the pair is lighted.
Considering the pair of lamps 46 and 47, the lamp 46 has cathode electrGdes 46A and 46B and the lamp 47 has cathode electrodes 47A and 47B. Cathode c c~ ~ c ~
electrode~ 46B and 47B are ~G~e~ in parallel to cathode heatiny winding 42. Cathode electrode 46A is connected to heating electrode winding 44. The heating windings 44 and 45 are shown in Figure 6 at the remote ends of their respective secondary windings. This is for convenience in drawiny. As described, the electrode heating windings 44 and 45 are wound on the secondary winding at the end of the secondary winding adjacent the primary winding.
Tlle cathode heating electrode 47A is connected b~ conductors 52 and 53 to two terminals of 7~S~
_ .
Case 2959 _ g _ a switch 51 which comprises six ganged double pole, single throw, switches. The single terminal side of switch 51 is designated 51Sl to 51S6, and the double terminal side is designated 51Dl to 51D12. Thus conductors 52 and 53 are connected respectively to 51S3 and 51S2. When switch 51 is in the upper position as shown in Figure 6, terminals 51S2 and SlS3 are connected to terminals 51D3 and 51D5 which in turn are connected to conductors 54 and 55. Conductors 54 and 55 are connected to cathode electrode 46A. Thus, with switch 51 in its upper position, cathode electrodes 46A and 47A are connected in parallel.
Also, with switch 51 in its upper position, conductor 26 is connected through switch terminals 51Sl and 51D1 to a conductor 56 which is connected to cathode electrodes 46B and 47B. A
ballasting or operating capacitor 57 connects the remote end of secondary 40 to cathode electrodes 46A
and 47A. In othex words, with switch 51 in its upper position, the lamps 46 and 47 are connected in parallel across secondary windings 40 and capacitor 57. In this configuration, when the power is applied, normally only one lamp of the pair of parallel lamps 46 and 47 will start and run.
The lamps 48 and 49 are connected in a similar manner to secondary winding portion 41 and ballast capacitor 58. The cathode heating windings are, in this case windings 43 and 45. It is believed no further explanation is required.
When switch 51 is in its lower position as seen in Figure 6, the switch terminals 51S2 and 51S3 are connected to terminals 51D4 and 51D6. This connects conductors 52 and 53 to conductors 60 and 61 which are in turn connected to a primary winding portion extension 62. Thus, cathode electrode 47A is now connected to a heating winding portion 62. The Case 2959 conductor 56 is no longer connected through switch 51. It will be seen that lamps 46 and 47 are now connected in series and are across not just the secondary portion 40 (and capacitor 57) but are across the secondary portion 40 and the primary portion 37.
The voltage available for two lamps in series is thus higher. A startiny capacitor 63 is in parallel with lamps 46 to provide sequential starting of the series connected lamps.
The lamps 48 and 49 are connected in a similar manner and operate in a similar manner. It is believed no further explanation is necessary.
In summary, by making the secondary windings, or at least a region of~the secondary winding adjacent the ~i-E~ar~ winding, available ~or placing a cathode electrode heating winding over the secondary winding to provide a suitable controlled heating current for a-e~hodc electrode, there is more room for the winding of heating windings. This is particularly useful where more than three cathode - heating windings are required on one~rapid start leading type ballast.
Claims (3)
1. In a lead type, rapid start, fluorescent lamp system, a ballast apparatus for a plurality of lamps, each lamp having a cathode electrode at each end thereof, comprising a magnetic core, a primary winding on said core and having first and second ends for connection to an alternating power source, at least one secondary winding on said core, adjacent to and inductively coupled with said primary winding, ballast capacitor means connected to said secondary winding, the series arrangement or said secondary winding and said ballast capacitor means being connected at one end to said primary winding, the other end being provided for connection to said lamps, a plurality of cathode heating windings to provide power to said cathode electrodes, at least one of said cathode heating windings being wound on said secondary winding in the region adjacent said primary winding,and in the region of said secondary winding having minimum change in flux density between no load conditions and operating conditions, and means for connecting said primary winding to said lamps.
2. A ballast apparatus for a lead type, rapid start, fluoroscent lamp system having a number of fluorescent lamps each having a cathode electrode at each end thereof, said number of lamps and the arrangement of said lamps requiring more than three cathode electrode heating windings to provide power for said cathode electrodes, comprising a ballast transformer means having a Case 2959 magnetic core with a central core member and two oppositely spaced parallel side core members joined at the ends thereof by end members, a primary winding on said central core member and having first and second ends for connection to a source of alternating power, at least the secondary winding on said central core member adjacent said primary winding and inductively coupled with said primary winding, one end of said secondary winding being connected to said primary winding, a ballast capacitor for each secondary winding having one side connected to the other end of said secondary winding and the other end providing a high voltage for said lamps, two cathode electrode heating windings wound on said primary winding and a third cathode electrode heating winding being a primary extension of said primary winding, said three cathode electrode heating windings providing power to respective ones of said cathode electrodes, a fourth cathode electrode heating winding wound on said secondary winding in the region adjacent said primary winding and in the region of said secondary winding having minimum change in flux density between no load conditions and operating conditions for providing power to a respective one of said cathode electrodes.
3. In a lead type, rapid start, flourescent lamps system, a ballast apparatus for four lamps operated as two pairs of lamps, each pair being in series, each lamp having a cathode electrode at each end thereof, comprising a ballast transformer having a magnetic core with a central core member and two side core members, a primary winding on said central core member having first and second ends for connection to an alternating power source, a first and second secondary winding on said central core member on either side of said primary winding, each said - 13 - Case 2959 secondary winding being adjacent to and inductively coupled with said primary winding, ballast capacitor means connected in a series arrangement with each of said secondary windings, one end of each said series arrangement being connected to said first end of said primary winding and the other end being connected to the cathode electrode at one end of a respective paid of said lamps, means connecting said second end of said primary winding to the other end of each said pair of said lamps, first and second cathode heating windings wound on said primary winding, and a third cathode heating winding being a primary extension of said primary winding said first cathode heating winding being connected to the cathode electrode at said other end of each said pair of lamps, a fourth and fifth cathode heating winding wound on said first and second secondary winding respectively in the region thereof adjacent said primary winding and connected to said one end of a respective one of said pair of lamps, and a starting capacitor in parallel to one of the lamps in each pair of lamps.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000498342A CA1271515A (en) | 1985-12-20 | 1985-12-20 | Filament winding arrangement in ballast transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000498342A CA1271515A (en) | 1985-12-20 | 1985-12-20 | Filament winding arrangement in ballast transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1271515A true CA1271515A (en) | 1990-07-10 |
Family
ID=4132141
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000498342A Expired CA1271515A (en) | 1985-12-20 | 1985-12-20 | Filament winding arrangement in ballast transformer |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1271515A (en) |
-
1985
- 1985-12-20 CA CA000498342A patent/CA1271515A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |