Abstract:
A gas discharge lamp assembly is provided wherein the regulator housing and the ballast housing are placed remote from each other. Further, an ignitor and a capacitor are added to the circuitry of the ballast housing to allow for the regulator&#39;s remote placement. Such gas discharge lamps are typically between 1000 Watts and 2000 Watts.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a lamp ballasting approach wherein the regulating device is placed in a remote location with respect to the ballast and lamp assembly. 
     BACKGROUND OF THE INVENTION 
     FIG. 1 depicts the equivalent circuit of a magnetically regulating lighting assembly  10  comprising a lamp  18 , a ballast  14 , and a regulating transformer  12  enclosed in a housing  16  which is typically used for H.I.D. (High intensity discharge) applications below the 1000 Watt level. These discharge lamps, below the 1000 Watt level, do not exhibit the overall performance desired for some lighting applications such as illumination of sports arenas, large industrial facilities and roadways where fixtures are elevated and/or spaced far apart. In such applications, a higher wattage lamp is desired. Such lamps, however, are not able to be ballasted in the manner shown in FIG.  1 . The size and weight of the ballast limits its ability to fit within most ballast housings and would result in a heavy lighting assembly creating a moment arm about the support pole. 
     Another disadvantage of magnetically regualting ballasts is excessive heat loss. Such systems are not desirable in high temperature environments because of the undesirable amount of heat dissipated by the ballast  16 . Accordingly, the size of the lamp (i.e. the wattage) is limited. There are applications, described below, wherein a higher wattage luminaire would be useful; however, such luminaires cannot be employed due to the significant heat loss of the ballast  16 . 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a system and method for powering a lighting device where one unit, containing the ballast, is proximate to the first end of a support structure, and a second unit containing the regulating transformer is distal to the first end and proximate to the support structure. 
     Another object of the present invention is to provide a housing containing the regulating transformer which is connected to a power supply and to a remotely located second housing enclosing the lamp and ballast. 
     Still another object of the present invention is to provide a system that employs a second housing containing a ballast, an ignitor, and a capacitor that provides a low impedance path for the ignitor to prevent excessive attenuation to the ignitor pulse. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, advantages and novel features of the invention will be more readily appreciated from the following detailed description when read in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a schematic circuit diagram for a lighting assembly; 
     FIG. 2 illustrates a conventional electromagnetic regulating transformer ballast structure; 
     FIG. 3 is a schematic diagram of a lighting assembly constructed in accordance with an embodiment of the present invention; 
     FIG. 4 is a schematic diagram of a lighting assembly constructed in accordance with an embodiment of the present invention; and 
     FIG. 5 depicts an elevated lighting assembly constructed in accordance with an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIG. 1, a magnetically regulating lighting assembly  10  comprises a lamp  18 , and a magnetically regulating ballast assembly consisting of a conventional regulating transformer portion  12 , and an inductive ballast  14 , which are constructed on the same magnetic frame. This lighting assembly is enclosed in a single housing  16 . 
     As shown in FIG. 2, the regulating ballast  16  consists of the power supply  20  connected to the primary coil  22 , a secondary winding  24 , and a tertiary winding  26 . Further, the tertiary winding  26  has a capacitor  28  connected in parallel. The three windings are coupled together by a laminated core  30 . Referring back to FIG. 1 the alternating current power source  20  is connected across the primary winding  22  of the regulating transformer portion  12  of ballast  16 . Equivalently, an inductor  32  is connected in series between the primary winding  22  and the power source  20 . The capacitor  28  is shown in parallel with respect to the primary winding  22 . The inductor  32  and the capacitor  28  are sized such that the peak voltage across capacitor  28  is in excess of the level necessary to drive the transformer, consisting of primary winding  22 , the secondary winding  24 , and a core  30 , into saturation. As this saturation level is exceeded, the output waveform of the regulating transformer  12  exhibits a square-wave characteristic. As the input voltage is increased, the level of saturation is increased, resulting in a more distorted or “flattened” secondary voltage. A magnetically-regulated ballast system is provided when this secondary voltage is used to supply a reactor ballast  14  and lamp  18 . 
     Such a lighting ballast assembly  16  is heavy relative to other ballast types that operate lamps of equivalent wattage. A 400 watt magnetically regulating ballast  16  can weigh approximately 26 pounds. An equivalent 1000 watt system can weigh on the order of 47.5 pounds, and an equivalent 1500 watt system can weigh at least 67.8 pounds. In these later two cases, it is difficult to mount these assemblies  10  within an existing lighting system. To employ these higher wattage lamps, there is a need to separate the regulating transformer  12 , which represents most of the weight in the lighting assembly  10 , from the ballasting function  14 . The ability to have the regulating transformer  12  remote from the ballasting function  14  allows for more stable placement of the regulating transformer  12 , and easier accessibility for maintenance. Further, one regulator  12  can be used to serve multiple lighting ballast assemblies  14  and lamps  18 . 
     The present invention provides for remote placement of the regulating transformer  12  with respect to the ballast  14 , as shown in FIGS. 3 and 4. With reference to the circuit diagram of FIG. 4, a regulating transformer  58  constructed in accordance with an embodiment of the present invention is similar to the regulating transformer  12  described above, except that it is preferably enclosed in a housing  42  that is independent of a housing  49  enclosing the ballast function  14 . FIG. 3 depicts the separate housings  42  and  49 , and wiring  60  therebetween. The wiring  60  is sized to minimize the voltage drop associated with the distance between the housings. 
     The ballast housing  49  has additional higher capacity circuitry to allow for higher wattage lamps  18  due to remote placement of transformer  58 . More specifically in FIG. 4, an ignitor  45  and capacitor  43  are added in parallel with the regard to ballast  14  and ignitor  45 , within the second housing  49 . The ignitor  45  is provided for pulse starting. Since the ignitor  45  is added, a capacitor  43  is preferably provided to create a low impedance path to prevent excessive attenuation of the ignitor pulse. 
     The tables below illustrate an improvement in performance of the regulating transformer and reactor with the addition of capacitor  43  by providing more consistent lamp color and illumination level over variations in supply voltage, as well as a decrease in the degradation of the light output over the life of the lamp. 
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Industry Standard Continuous Wattage Autotransformer (CWA) 
               
             
          
           
               
                 Nominal Volts Input = 277 VAC 
                 Regulation = ± 10% 
               
               
                 INPUT 
                 OUTPUT 
               
             
          
           
               
                 V 
                 A 
                 W 
                 PF 
                 THD 
                 V 
                 A 
                 W 
                 CF 
                 REG 
               
               
                   
               
             
          
           
               
                 277 
                 1.67 
                 447 
                 .964 
                 18.1 
                 140.1 
                 3.11 
                 386.9 
                 1.62 
                 N/A 
               
               
                 304.7 
                 1.69 
                 495.5 
                 .959 
                 27.5 
                 141.3 
                 3.36 
                 422.6 
                 1.61 
                  +9.2% 
               
               
                 249.3 
                 1.59 
                 388.6 
                 .979 
                 17.0 
                 138 
                 2.73 
                 340.1 
                 1.65 
                 −12.1% 
               
               
                   
               
               
                 OCV: 240 rms/452 pk  
               
               
                 SCA: 3.67 rms/6.43 pk  
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Ballast 14 with capacitor 43 
               
             
          
           
               
                 Nominal Volts Input = 240 VAC 
                 Regulation = ± 10% 
               
               
                 INPUT 
                 OUTPUT 
               
             
          
           
               
                 V 
                 A 
                 W 
                 PF 
                 THD 
                 V 
                 A 
                 W 
                 CF 
                 REG 
               
               
                   
               
             
          
           
               
                 239.6 
                 2.02 
                 447.0 
                 .925 
                 17.3 
                 140.2 
                 3.19 
                 419.1 
                 1.47 
                 N/A 
               
               
                 264.3 
                 2.29 
                 528 
                 .875 
                 16.4 
                 141.2 
                 3.72 
                 488.0 
                 1.48 
                 +16.4% 
               
               
                 216.7 
                 1.75 
                 362.4 
                 .957 
                 19.8 
                 137.2 
                 2.68 
                 341.9 
                 1.51 
                 −18.4% 
               
               
                   
               
               
                 OCV: 241.5 rms/334.5 pk  
               
               
                 SCA: 4.40 rms/6.10 pk  
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Regulating Transformer 12 with out Capacitor 43 
               
             
          
           
               
                 Nominal Volts Input = 480 VAC 
                 Regulation = ± 10% 
               
               
                 INPUT 
                 OUTPUT 
               
             
          
           
               
                 V 
                 A 
                 W 
                 PF 
                 THD 
                 V 
                 A 
                 W 
                 CF 
                 REG 
               
               
                   
               
             
          
           
               
                 483.4 
                 1.01 
                 438 
                 .895 
                 16.5 
                 139.1 
                 2.8 
                 364 
                 1.54 
                 N/A 
               
               
                 528.1 
                 1.20 
                 456 
                 .722 
                 30.0 
                 139.8 
                 2.85 
                 369.3 
                 1.544 
                 +1.5% 
               
               
                 431.7 
                 .979 
                 414.7 
                 .981 
                 2.43 
                 138.9 
                 2.68 
                 348 
                 1.55 
                 −4.4% 
               
               
                   
               
               
                 OCV: 257/rms/392 pk  
               
               
                 SCA: N/A  
               
             
          
         
       
     
     
       
         
               
               
             
               
               
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Nominal Volts Input = 480 VAC 
                 Regulation = ± 10% 
               
               
                 INPUT 
                 OUTPUT 
               
             
          
           
               
                 V 
                 A 
                 W 
                 PF 
                 THD 
                 V 
                 A 
                 W 
                 CF 
                 REG 
               
               
                   
               
             
          
           
               
                 480.6 
                 1.17 
                 526.2 
                 .937 
                 11.83 
                 140 
                 3.13 
                 410 
                 1.53 
                 N/A 
               
               
                 528.1 
                 129 
                 538.8 
                 .792 
                 26.0 
                 140.5 
                 3.144 
                 409.9 
                 1.528 
                   +0% 
               
               
                 432 
                 1.19 
                 505.6 
                 .985 
                 4.23 
                 139.6 
                 3.05 
                 395.4 
                 1.54 
                 −3.56% 
               
               
                   
               
               
                 OCV: 257/rms/393 pk  
               
               
                 SCA: 4.27 rms/5.76 pk  
               
             
          
         
       
     
     Tables 1 and 4 provide performance information for an industry standard continuous wattage autotransformer (CWA) and the lighting assembly  10  of the present invention, respectively. Specifically, comparing the REG columns (regulation function) of Tables 1 and 4 there is a smaller differential between the supply voltage and lamp power variations exhibited by the present invention. Similar to Table 1, Table 2 containing ballast  14  exhibits poor regulation, however this regulation improves by the addition of the regulating transformer  12 , as can be seen in Table 4 of the present invention. The regulation function allows for consistency of color and illumination levels. Further, comparing the PF power factor and THD total harmonic distortion columns of Tables 3 and 4, the addition of capacitor  43  allows for a higher power factor correction and a reduction in total harmonic distortion. Tables 3 and 4 use nominal volt inputs of 480 VAC however, they use a stepped down transformer to a nominal 240 VAC. A comparison of column CF crest factor of Tables 2 and 4 shows a decrease in crest factor thus lessening the degradation of light output over the life of the luminaire. 
     While only one advantageous embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims.