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HPS SERVICING GUIDE - American Electric Lighting

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1. HPS SERVICING American Electric Lighting KEL AnSAcuityBrands Company High Pressure Sodium Servicing Guide Table of Contents OVERENS 3 IMPORTANCE OF SAFETY rrunnnnernnenennnnrennnnennnnnen 3 INTRODUCTION TO HID LIGHTING 4 Incandescent LAMPS ccccccceeeceeeeeeeeeeeeeeeees 4 Fluorescent Lamps cccsscceseceeeceeeseseseeeees 4 HD UA igede a 4 HID OPERATION AND CONSTRUCTION 5 Mercury Vapor and Metal Halide Lamp Starting 6 PANS ES 26 sececc sd dovesscat ee ncte teseae TO 7 Arc Tube DCS Ne 7 HPS End of Life Voltage ccccsccesseeeeeeeeees 8 HID OPERATING CHARACTERISTICS 06 8 TABLE 1 HPS Lamp Date Lunsj 9 HID LAMP LUMEN MAINTENANCE 006 9 HPS LAMPS EEE veces 10 Mercury Vapor Lamps uesrnmemnvnesms suse 10 Metal Halide Lamps ssrnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 10 HID LAMP LIFE 255 10 APSL AD as ER 10 Mercury Vapor Lamps arrnnnrnnnrnnnnnnnnnnnrnnnnnnnnn 11 Metal Halide Lamps rnnnnnnnnnnronnnnnnnrnnnrnnnnnnnrn 11 THE HPS LUMINAIRE ccseccscecssncsovnacesnceatneseesacectset 11 HPS Lamp Starters arrrrnrernnnrnnnnnvnnrnvanennnnnnnn 11 Starter Operation lt s ccc cccssdiecceseesceneceeeeeceeeens 11 Starter Variations rranrrrarrrnnrrnnerenanrnnnnennanennn 13 Instant Restrike Starters rarrrranrrrrnrrvnnrrvnnennn 13 Two Lead Starters rrrnnrrnnrr
2. Volts x Power Factor The power factor is the ratio of the active power as read on the wattmeter to the product of the volts and amperes as read on meters placed in the HID circuit This ratio usually is expressed as a percentage Total Watts Active Power Factor Amperes x Volts Using the equation Total Watts Volts x Amperes x Power Factor it is easy to see how the power factor of a ballast affects the total current in a circuit When the power factor is 100 the current is at a minimum and the product of the amperes and volts is equal to the active watts as measured by a wattmeter However if the ballast has a power factor of 50 the current in the circuit is doubled If the ballast power factor is 90 the current will be increased by only 10 Failure to consider the effect of power factor on the current especially when the circuits are heavily loaded can result in overheated wires excessive voltage drop or interruptions caused by the operation of protective equipment 15 TABLE 2 BALLAST CHARACTERISTICS FOR HID LIGHT SOURCES Mercury Vapor HPS Regulated Constant Constant Ballast Type Reactor Auto Auto CWA Wattage CW Voltage Typical Line Voltage 240 120 ei i Lamp Wattage Change 12 12 5 2 1 2 10 Input Voltage Change 5 5 10 13 10 Power Factor P F 50 50 90 90 90 Capacitor Std Std Std Mercury Vapor X X X X Metal Additive x Metal Additive for approved
3. 55 volt fixture will cause cycling because the 55 volt ballast does not supply the necessary voltage required by the 100 volt lamp Make sure lamp matches fixture FIGURE 17 Checking the correct lamp 19 Using a lower wattage HPS lamp in a higher wattage fixture such as a 70 watt lamp in a 150 watt fixture also may cause cycling Using the wrong or defective ballast or capacitor also can lead to cycling Also be sure the ballast and capacitor are wired correctly Reignition Phenomenon HPS and other HID lamps actually turn ON and OFF 120 times per second Current is cut off for a millisecond or so at each midpoint or zero crossing point of the AC 60 Hertz cycle Figure 18A The lamp stays hot enough to automatically restrike after this very very short outage However if several cycles of the AC power are lost or drop out due to loose wire connections or shorts the lamp cools sufficiently to turn OFF and will not restrike immediately Figure 18B To avoid dropouts due to poor connections do not pull the wires tight when installing the luminaire or its internal components such as the ballast photocontrol starter or capacitor The lamp must be screwed into the socket properly to make a good connection The coil spring must be compressed completely to make proper contact at the base of the socket All of the metal on the lamp s screw base should be hidden below the rim of the socket when the lamp is screwed in comple
4. 000 plus hours Normal end of life occurs when the lamp begins to cycle on and off due to excessive lamp voltage rise Approximate Lumen Maintenance of Metal Halide Lamps 100 Initial Lumens Percent O 12 16 20 24 0 20 40 60 80 100 Rated Average Life Percent FIGURE 7 HID lamp lumens maintenance curves A HPS B mercury vapor C metal halide Approximate Survival Curve of HPS Lamps Survival Percent Initial Lumens Percent gt OO 16 Hours Burned Thousands Hours Burned Thousands Approximate Survival Curve of Metal Halide Lamps Approximate Survival Curve of Mercury Vapor Lamps Initial Lumens Percent O Rated Average Life Percent FIGURE 8 HID lamp life curves A HPS B mercury vapor C metal halide 10 American Electric Lighting An SAcuityBrands Company More frequent starts will cause voltage to rise faster as will overwattage operation Slight underwattage operation will have no adverse effect on lamp life Mercury Vapor Lamps Mercury vapor lamps have an extremely long rated life exceeding 24 000 hours Figure 8B Mercury lamps should be replaced before they burn out due to decreases in lumen output Frequent starting does not adversely affect lamp life as significantly as other HID lamps The normal mode of failure is the inability to start Metal Halide Lamps Metal halide lamps have an average rated life span of 3 000 to 20 000 hours depending o
5. Electrode Arc Tube Main Electrode Glass Bulb Self Extinguisher Supports Arc Tube Seal Arc Tube Main Electrode Glass Bulb HPS LAMP RETROFIT MERCURY VAPOR FIGURE 3 Components of HID lamp designs BALLST HPS LAMP American Electric Lighting 5 AnSAcuityBrands Company Mercury Vapor and Metal Halide Lamp Starting As just mentioned both mercury vapor and halide lamps use a separate starting electrode This starting electrode is located next to one of the main electrodes inside the arc tube The start up electrode allows these lamps to be started using a much lower start up voltage than required by HPS lamps When a mercury vapor or metal halide lamp is energized an electrical field is generated between one of the main electrodes and the starting electrode next to it This causes an emission of electrons that ionize the argon starting gas The ionized argon particles create a diffused argon arc between the two main electrodes of the lamp Figure 4 The heat from this argon arc gradually vaporizes the arc metals in the arc tube These ionized arc metal particles join the arc stream between the two main electrodes When a sufficient number of ionized Main Electrode lonized Argon Gas Arc Tube Electrical Field Main Electrode Starting Electrode Starting Resistor Ballast El GID Voltage to Lamp FIGURE 4 Mercury vapor or metal halide lamp particles join the arc stream th
6. against that in the luminaire Dim Burners Adim burning or low output fixture usually is caused by having the wrong wattage lamp installed in the fixture such as a 55 volt lamp in a 100 volt fixture or a 100 watt lamp used in a 50 waitt fixture or a 150 watt light bulb installed in a 70 or 100 watt fixture Check and or install a new correct size lamp Low supply voltage also can cause a dim burner Measure the supply voltage across the terminals and make certain it matches the rating on the ballast voltage label Improper wiring of a multi tap ballast is another cause of low light output Check and correct any miswiring On regulated ballast fixtures a disconnected or defective regulating capacitor also can cause a dim burning fixture Be sure the correct capacitor is used and that it is wired correctly Day Burners A fixture that burns night and day usually has a defective photocontrol Replace the photocontrol If the problem persists check for open wiring usually the white wire from the photocontrol receptacle is open If the problem still exists replace the fixture Also replace the fixture if there is evidence of heat damage to the photocontrol receptacle Short Life Lamps If the lamp burns out shortly after being installed check for proper match up of lamp ballast and capacitor ratings Check a similar properly operating luminaire for the correct capacitor size or refer to manufacturer s specifications Finally ch
7. check for intermittent open circuits and poor connections in the lamp and fixture Drop Out Occurs FIGURE 18 A Voltage actually is cut to the lamp every time alternating current changes direction This happens 120 times per second with 60 Hertz AC power B When several cycles of AC current drop out or are lost the lamp will turn OFF 20 American Electric Lighting An SAcuityBrands Company For example the lamp s internal mounting frame is designed to allow the arc tube to move as it expands and contracts with changes in temperature The metal mounting frame is stable but the arc tube connects to the lamp base through the use of a flexible bond strap Over time the bond strap weld can fail causing intermittent contact A bump test often will detect this type of failure Keep in mind that normal end of life cycling is marked by amore or less predictable on off pattern of a minute or so ON and a minute or so OFF Cycling caused by open contacts or bad welds is much more unpredictable The lamp may stay ON or OFF for several minutes or several hours When you field test a lamp with cycling problems remember to test the photocontrol operation As the lamp starts to come up bump it to see if you can make it cycle OFF You may even be able to see the slight electrical arcing at the bad connection You also should bump test the lamp after it has started and stabilized Thermal Cycling Thermal cycling is another v
8. condition Experience has shown that during the first 20 minutes or so of HPS lamp operation the lamp voltage may rise or fall from start to start or even during continuous operation as varying amounts of amalgam enter the arc stream Most HID lamps use a wire support frame to protect cushion and align the arc tube in the center of the bulb The design and placement of this support frame is particularly important in HPS lamps because it can affect the temperature of the arc tube and end caps As we have seen arc tube temperature has a direct effect on the amount of amalgam vaporized The construction and composition of the HPS main electrodes also are very critical Material discharged from the electrodes during start up and operation redeposits on the arc tube ends in much the same way the tungsten filament of an incandescent lamp evaporates and blackens the bulb This blackening of the arc tube also will increase operating temperatures and voltage across the arc tube HPS End of Life Voltage With a number of factors contributing to HPS lamp voltage rise the increase in operating voltage over the life of the lamp becomes significant The operating voltage of HPS lamps increases about 1 2 volts per 1000 hours operated The life of an HPS lamp is dependent on the rate of lamp voltage rise Lamp voltage will rise until it reaches the limit of the ballast voltage available At this point the HPS lamp will cycle ON and OFF and it
9. electrodes As soon as this arc is established the voltage pulse is switched off Sodium and mercury arc metals quickly vaporize and join this arc stream and the arc current increases and stabilizes HPS lamps generate a sodium based light that is strongest in the yellow and orange range of the spectrum and weakest in the blue green wavelengths American Electric Lighting AnSAcuityBrands Company A small amount of mercury is added to the arc tube to help strengthen blues and greens but the overall color rendering is still golden white with both reds and blues appearing grayed Ballasts All three types of HID lamps require the use of a ballast to assist in starting and limiting the current across the arc once the arc has been struck Remember that HID lamps are negative resistance lamps If a ballast were not used the arc discharge would draw an unlimited amount of current and the lamp quickly would be destroyed More complete ballast information can be found later in this manual Arc Tube Design The arc tube of mercury vapor and metal halide lamps is shorter and wider in diameter than an HPS arc tube This allows room for the starting electrode Mercury vapor and metal halide arc tubes are thin walled tubes made of high quality quartz The ends of the tube are sealed by flame forming This one piece press fit construction assures greater uniformity between lamps and also holds and protects the thin leads of the e
10. it closes the contacts to the ballast Line voltage is applied to the ballast and the lamp begins its start up sequence The lamp will operate until the light of sunrise again decreases resistance in the cell This initiates current flow to the relay coil The coil energizes and its magnetic field pulls the relay armature closed This cuts line voltage to the ballast and the lamp turns OFF The photocontrol works because it uses a sensitive relay that operates on a very slow changing voltage The relay reacts to any voltage less than system voltage An operational photocontrol will emit a soft humming noise as it approaches its pull in voltage You will hear a slight click as the relay contacts close American Electric Lighting An SAcuityBrands Company A defective or damaged photocontrol will emit a growling noise as it nears its pull in voltage This sound resembles a door bell buzzer and usually is caused by misaligned relay contacts The photocontrol may continue to growl and never completely close its contacts Or it may growl and then close its contacts In either case never use a photocontrol that can be made to growl or buzz during testing Test photocontrol operation by covering the photocell with your hand to simulate darkness Figure 16 It should click open as you cover it and then click closed when you remove your hand Repeat this test several times to center the relay armature Now cover the cell completely and th
11. location in the field a properly trained service technician should be able to troubleshoot repair or replace the defective fixture within a 10 to 15 minute time frame This 15 minute service call relies on a consistent logical approach to troubleshooting an understanding of HPS operation and the proper use of test equipment Make certain you take a known good HPS lamp a luminous wattmeter and a voltmeter on all service calls The 15 minute service call is based on some very real economic facts of life It takes time to travel to the job site and set up the lift truck or ladder If the service technician then spends much more than 15 minutes servicing one particular luminaire the cost of his or her time begins to approach or exceed the actual cost of the luminaire If the problem cannot be pinpointed and corrected in this time frame the luminaire should be removed and replaced The service technician also must take this opportunity to quickly inspect the entire luminaire Look for potential future problems and repair them on this service call Take a minute or two to look for charred or heat damaged surfaces or photocontrol receptacle Also check for pinched wires and hot spots on ballasts that may signal failure in the near future Check the fixture mounting The housing should be level and all mounting bolts and clamps should be present tight and in good condition 25 HPS Luminaire Failures Following are common luminaire fail
12. of three isolated coils on a core of steel If Matching Lamp and Ballasts It is very important to match lamp and ballast to attain proper lumen output and lamp life HPS lamps rated at 55 volts can use a single coil reactor type ballast having a separate starting circuit A secondary coil is not needed in this case for voltage step up and the single coil ballast generates less heat When installing replacement lamps be sure the lamp voltage and wattage rating match the ratings of the fixture and ballast For example installing a 150 watt 55 volt HPS light bulb in a fixture equipped with a 150 watt 100 volt ballast will result in a dim burner This is because the given ballast limits current to the lamp to 1 8 amperes A 150 watt 55 volt HPS lamp requires 3 2 amperes of current to reach full brightness Ballast and lamp wattages must also match Installing a 250 watt lamp in a 175 watt ballast fixture will result in a dim burning lamp On the other hand installing a 175 watt lamp in a 250 watt fixture will drastically reduce lamp life Adim burner also can be caused by a shorted or incorrect capacitor PHOTOCONTROL OPERATION AND TROUBLESHOOTING HID fixtures used in outdoor lighting applications such as roadway area site and security lighting can be equipped with photocontrol units that automatically turn the fixture on at dusk and off at dawn Figure 14 FIGURE 14 Typical photocontrol for HID luminaire The phot
13. operation and it gives a visual indication of the circuit s ability to carry current This makes it an excellent tool for determining the cause of luminaire outages in the field The following is an example of how the luminous wattmeter can be used to troubleshoot an outage 24 1 Begin by testing the photocontrol with the hand test explained earlier Replace if defective 2 If the outage is not corrected replace the HPS lamp with a known good lamp 3 If the known good lamp does not start remove it and install the luminous wattmeter As you install the luminous wattmeter do not stop until the base is fully bottomed out in the socket and mechanically stressed In some cases the lamp may turn ON partway in and then turn OFF again when tightly installed The lamp also may start to blink or turn ON and OFF This could indicate a loose screw in the socket or a bad base to socket connection ora shorting of the lamp socket connector to the lamp mounting bracket 4 If the luminous wattmeter lights it indicates that the luminaire has a good power system to fixture connection Power is passing through the terminal board through the ballast and out through the wiring and connections to the incandescent lamp That quickly lets you know all these possible trouble spots are functioning correctly Since the incandescent works and the HPS lamp does not all evidence points to a defective starter Replace the starter and install the
14. or better when there is almost no delay in the current flow Power factor is normal about 50 when current flow is delayed See point N in Figure 21 Resistance Resistance limits or controls the flow of current All conductors offer some resistance to current flow Resistance can be compared to the amount of friction between the flowing water and the pipe walls in a plumbing system 27 Secondary The customer side of a power company s distribution transformer where the service drop for the luminaire is connected Short Circuit An accidental path of low resistance that passes an abnormally large amount of current short often occurs as a result of improper wiring or broken insulation Power Factor 50 Voltage Voltage is electric pressure It can be compared to water pressure in a plumbing system It also is a force referred to as electromotive force emf Other terms used for voltage are potential and potential difference The volt is the unit of electric pressure Watts Loss The difference between the amount of power supplied to a luminaire ballast and lamp and the amount of power actually used by the lamp itself Current Time 1 60 Second gt gt This illustration represents a 120 volt waveform The voltage ranges from zero to 177 volts to zero to 177 to zero 60 times a second The average voltage is 120 volts FIGURE 21 Graphic representation of normal power factor ballast 28 Am
15. premature lamp cycling or an outage Excessive starting voltages also can short out the ballast resulting in ballast burnout or can break down the lamp socket or the lamp base internally If the starting pulse is too low then lamp starting will become unreliable early in lamp life The two lead starter eliminates mismatching problems when used with various manufacturers ballasts The two lead starter operates on the lamp socket voltage which is an ANSI standard 13 Ballast A 3 terminal Covers Remove Tap Connection or Insulate FIGURE 12 Two lead starters have their own ignition coil It produces its own step up voltage pulse and sends it to the lamp When the two lead starter is installed the lead on the ballast that runs from the ballast tap to the starter is disconnected This disables the starting function of the ballast now handled by the two lead starter However the ballast still can perform its other current and voltage regulation functions Two lead starters are ideal for users that must maintain a wide range of luminaires built by different manufacturers They also solve the problem of obtaining properly matched replacement parts HID LAMP BALLASTS As we have discussed the ballast performs a number of important functions in HID lamp operation These include 1 Providing the correct starting current 2 Providing the correct starting voltage 3 Limiting current to the lamp The most basic func
16. replacement program 22 Visual Inspection Before performing any electrical tests lamps and luminaires should visually be inspected for manufacturing defects and damage due to shipping and handling Lamps Inspect all lamps for the following e Broken internal welds e Bent arc tube supports that allow an arc tube misalignment of more than 3 e Loose screw base e Broken arc tube mountings e Broken electrodes e Defective vacuum seal indicated by a white chalk like deposit inside the lamp envelope This condition may occur before or after the electrical test Luminaires Inspect all luminaires for the following e Broken refractors e Broken lamp sockets e Broken or bent luminaire housing e Loose or broken screws e Broken or damaged electrical components e Good optical assembly seal and alignment Smooth working housing hinges hinge keepers and latches e Any loose electrical connections kinked wire abraded wire stripped or overtight terminal block connections etc e The presence of wildlife shields fitter clamps and all equipment and options predescribed by the luminaire manufacturer s presubmitted sample Any damaged or missing component on the lamp or luminaire is reason for rejection If it is apparent that shipping and or handling damage has occurred the source of the damage should be determined and the responsible parties notified Lamps and luminaires that pass visual and mecha
17. that your body is an excellent conductor of electricity Water also is a great conductor Air and insulating materials such as rubber and plastics are poor conductors Current Electricity in motion It is the flow of electrons through a conductor Voltage is the force or pressure that drives the current through the conductor Current flows only between points having a difference of potential The ampere or amp is the unit of current measurement Electric Circuit A path or a group of interconnected paths capable of carrying electric current Electron A single microscopic particle with an electrical charge lt can be compared to a drop of water in a water pipe In atoms electrons orbit around the nucleus Current flow occurs when electrons break free of their orbits and jump from atom to atom Fixture See Luminaire Frequency In lighting applications powered by alternating current voltage and current vary rapidly over American Electric Lighting AnSAcuityBrands Company a very short period of time Acycle occurs each time a pattern of variation completes The number of times a cycle occurs each second is the frequency Hertz of the voltage and current Voltage and current in the United States and most of the world completes 60 cycles each second Direct current such as that generated by storage batteries is not cyclical lon An atom or molecule that has an electrical charge Lamp The actual assembly tha
18. way as in the automotive ignition coil previously described Current from the charged capacitor passes through the 10 to 12 windings of the ballast tap creating a magnetic field When the starter s electronic switch opens the capacitor s path to the ballast tap is momentarily broken and the magnetic field collapses inward toward the center of the ballast output coil The magnetic lines of force that were created in the tap windings cut across the hundreds of turns of fine wire that make up the output coil As a result the electron balance in the output coil wire is upset and voltage is produced in the output coil windings The current flow from the output windings has high voltage because the output coil is made of hundreds of wire turns As the magnetic field falls inward it cuts across each turn of wire generating a certain amount of voltage in each loop Since the loops are connected in series the voltage produced in one loop is added to the voltage produced in the succeeding loops By the time the lines of force have fallen all the way to the center of the output coil the necessary 2500 to 4000 volt starting pulse has been generated ET Starter Tap Finish FIGURE 11 Ballast tap acts as a primary coil American Electric Lighting AnSAcuityBrands Company In effect the ballast acts like a step up transformer For example consider a ballast with 10 turns of wire in its tap coil and 300 turns of wire in its output
19. when adapting the incandescent lamp to the HPS mogul socket If only a medium to mogul adapter were used it would be difficult to install the incandescent tight enough to stress the connection The weaker incandescent lamp medium base to medium socket connection at the adapter may become stressed and break shattering the lamp Usually there is little problem screwing the adapter into the mogul socket The problem is in safely removing it without breaking the incandescent The solution is to screw the incandescent into the medium to mogul adapter and then screw the mogul end of the adapter into one end of a mogul to mogul extender The other end of the mogul to mogul extender is then screwed into the mogul socket of the HPS luminaire It is possible to tightly grip the body of the extender without damaging or stressing the incandescent lamp or its base Note While the medium to mogul adapter is a common piece of hardware the mogul to mogul extender can be more difficult to find One source for the extender is the Leviton Manufacturing Company Inc Order through your electrical distributor Some lower wattage HPS lamps and luminaires can be equipped with medium bases and sockets that match the incandescent lamp The luminous wattmeter can be screwed directly into these sockets Advantages of the Luminous Wattmeter The luminous wattmeter has several distinct advantages as an HPS troubleshooting tool It does not require a starter for
20. 00 pretesting may be more economical if the lamps and luminaires are to be installed in a high cost maintenance location such as a high traffic roadway near a major airport Spot lamp replacement in these areas can cost several hundred dollars for a single lamp If a 5 to 7 sampling is being used be sure to select the lamps and luminaires from different batches or runs in your equipment inventory Check the run or batch number that appears on the lamp or luminaire carton This usually is either a code number or an actual run date indicating the day and time the unit was manufactured Keep in mind that code numbers and or dates that appear on the actual lamp or luminaire usually are warranty related and do not necessarily indicate the date and time of manufacture The reason you should select equipment from different batches or runs is simple lamp and luminaire manufacturers usually make mistakes between batches not between individual lamps or luminaires Changes in raw materials manufacturing methods or worker inspection can lead to a bad run of equipment before the problem is realized and corrected These bad runs will have an inordinate percentage of defective units whereas a good run may have only an occasional oddball defect Your test group should contain units from all runs or batches in your inventory If a bad unit is found further testing of units in that batch may uncover a defective run that could play havoc with your spot
21. E 2 Typical fluorescent lamp components American Electric Lighting AnSAcuityBrands Company HID OPERATION AND As the arc tube is manufactured small amounts of special arc metals such as mercury halide compounds CONSTRUCTION or sodium are sealed inside the tube Starting gases Such as argon neon or xenon are placed inside the All HID lamps share a number of design and operating tube The arc tube also houses the lamp s two main features but there are some important differences electrodes plus the separate starting electrode used between mercury vapor metal halide and HPS lamps in mercury vapor and metal halide lamps Figure 3 An HID lamp produces light in much the same manner All HID lamps contain a sealed arc tube mounted inside as a lightning bolt But instead of a brief flash the a glass bulb In mercury vapor and metal halide lamps electric arc between the lamp s two main electrodes is the bulb is filled with hydrogen gas which absorbs the continuous The striking and maintaining of this ultraviolet radiation produced during operation HPS continuous arc Is made possible by the starting gases lamps have a vacuum inside the bulb to isolate the arc and arc metals sealed inside the arc tube The proper tube from changes in ambient temperature start up voltage also is needed to establish the arc Lamp start up is not the same for all HID lamps Supports Resistors Arc Tube Seal Main Electrode Starting
22. HPS lamp In the vast majority of cases the lamp will now start If it does not start replace the entire luminaire if no other physical damage is found 5 If the luminous wattmeter does not light when installed in step 3 it indicates other problems such as an open connection at a luminaire component a blown line fuse or no power to the luminaire Check for burned or damaged fixture components and for loose or disconnected electrical connections Use a voltmeter to check supply voltage Is it the same as the fixture is rated for Check for correct and functional photocontrol operation You also should check for a missing or defective capacitor bleed resistor across the regulating capacitor when a two coil regulating ballast is used Note In a rare case when the bleed resistor is open the charge on the capacitor can cause the starter to remain in the OFF position and the lamp will not start American Electric Lighting AnSAcuityBrands Company When the luminous wattmeter does not burn leave the luminous wattmeter in the luminaire and troubleshoot the problem until the incandescent can be made to light If the problem cannot be found replace the luminaire Two Problem Outages Occasionally two distinct problems could be the cause of the outage For example a given luminaire could have an intermittent power connection to the fixture The arcing caused by the bad connection also could cause a starter circuit failure Whe
23. It is used when the line voltage is 120 volts and socket voltage is in the 240 volt range This ballast consists of two coils on a core of steel Together the tap and output coils transform the line voltage into the required starting voltage American Electric Lighting AnSAcuityBrands Company i Capacitor Optional paring Mercry Vapor Reactor Ballast Circuit Common I r Capacitor 8 EO HPS Constant Wattage Autotransformer Ballast Circuit Common e EO Capacitor HPS High Reactance ats Autotransformer Ballast Circuit Capacitor na Optional Common HPS Reactor Ballast Circuit Constant Wattage Line Autotransformer Ballast Circuit Common High Reactance Autotransformer Ballast Circuit Capactor Common Line2 Constant Wattage Ballast Circuit aK OL Line2 HPS Constant Voltage Ballast Circuit FIGURE 13 Circuit diagrams for various types of ballasts used in HID applications The ballast also limits lamp current Lag auto ballasts have the same operating and performance characteristics as reactor ballasts This type of ballast normally is used with mercury vapor and HPS lamps Constant Wattage Autotransformer Ballasts These ballasts also are called regulated or autoregulator ballasts The constant wattage autotransformer CWA ballast consists of two coils on a core of steel and a capacitor in series with the lamp CWA ballasts perform the basic jobs of
24. PS LAMPS This requirement is for lag circuit regulated or non regulated ballast designs I LAMP PHYSICAL CHARACTERISTICS Arc Tube Support Member PE sm Mogul Screw PUD E18 Borosilicate Lead Glass Arc Tube Overall Length 244 4mm 9 5 8 Maximum Diameter rrrarrrnnrennnnnnnre 57 1mm 2 1 4 Approx Light Center Length 146 3mm 5 3 4 Approx Electrode Arc Length rrrrnnnnnnnnnn 87 2mm 3 3 8 Approx Maximum Bulb Temperature rrrnrrnnnnnennnnnr 400 C installation Maximum Base Temperature rrrnrrrnnnnernnnnr 210 C Code ll LAMP ELECTRICAL CHARACTERISTICS RMS Values Electrode Amalgam Resevoir Outer Envelope A Wattage BR N EEE en se Sodio 2 ecto NE NE 400 watts Permitted Operating Range for Rated Lamp Life rrrrrrnnrrrnnrrnnnernnnennrr Min 300 watts Max 475 watts B Characteristic Voltage Rated Voltage Design Center rrarrrnnnrnvvnnnrvnnnrnnnnnrnnnnnnnnnnsnnnnnrnnnnrnnnnsnnnnnennnnnen 100 volts amp 400 watts Voltage Range at 100 HOUrs rrrrnnnrnnnnvnnnnnvnvnnnnvnnnennnnrnnnnnrnvannnnnansnnnnsrnnnnennnnnene 90 115 volts amp 400 watts Maximum Lamp Voltage Luse s nnene 140 volts C Current Ve Current RMS 44424 4 7 amperes nominal Current During Warm Up RMS rrarnnnnnennnnrnnnennnnennnnnrnnennnnnnnnenn Min 4 7 amperes Max 7 0 amperes Curent Crest Factor EEE EEE EEE Max 1 8 D Operating Limits The trapezo
25. ained light output of HID lamps TABLE 1 HPS LAMP DATA Minimum ANSI Lamp Rated Rated Socket Code Watts LampLife Voltage Voltage 576 35 16 000 Hrs 52 110 568 50 24 000 Hrs 52 110 S62 70 24 000 Hrs 52 110 554 100 24 000 Hrs 55 110 555 150 24 000 Hrs 55 110 55 volts 556 150 24 000 Hrs 100 198 100 volts S66 200 24 000 Hrs 100 198 550 250 24 000 Hrs 100 198 S57 310 24 000 Hrs 100 198 S51 400 24 000 Hrs 100 198 S52 1000 24 000 Hrs 250 456 1 Rated lamp life is based on 50 survival Average NEW Lamp Nominal End of Life Volts Increase Voltage Range Lamp Lamp Per 1 000 at 100 Hours Amps Voltage Hours Life 46 62 0 83 84 es 46 60 1 18 84 1 5 45 60 1 60 84 1 5 44 62 2 10 84 1 5 48 62 3 20 88 1 5 85 115 1 80 160 1 5 90 115 2 40 160 1 5 90 120 3 00 160 1 5 90 120 3 60 160 19 84 115 4 60 140 1 5 210 275 4 70 350 1 5 2100 hours is lamp manufacturer specification for stabilizing light output 3 Also called open circuit CAUTION Disconnect starting lead not common to the lamp to eliminate the starting voltage when checking the minimum open circuit voltage The starting voltage may damage your voltmeter American Electric Lighting AnSAcuityBrands Company HPS Lamps HPS lamps have excellent lumen maintenance Figure 7A HPS lamps still are generating 90 of initial light output at the midpoint of their life span Lumen maintenance at the end of life still is excellent at around 80 Me
26. amp the arc discharges through the combined vapors of mercury and certain compounds of iodine The halide compounds help strengthen yellows greens and blues so the overall color rendering of metal halide lamps is green white Reds and oranges appear dulled Phosphor coatings on the bulbs of mercury vapor and metal halide lamps can improve color rendering and provide light diffusion Once a mercury vapor or metal halide lamp starts voltage drops to lower operating voltage levels A resistor or thermal switch in series with the starting electrode now blocks voltage to the starting electrode so it does not arc and burn out during normal lamp operation The arc tube of an HPS lamp is too narrow to house a separate starting electrode Since there is no starting electrode in an HPS lamp a much higher start up voltage is required to establish an arc between the wide gaps of the main electrodes This low power high voltage spike ranges between 2500 and 4000 volts This voltage spike or pulse is provided by a starter pulse circuit board separate from the ballast Figure 6 Note Some lower wattage metal halide lamps 70 100 and 150 watt also have arc tubes that are too narrow to house separate starting electrodes These metal halide lamps now use an external starter board such as those used in HPS lamps When an HPS lamp is energized the high voltage pulse ionizes the xenon gas in the arc tube and an arc is established between the main
27. ands Company FIGURE 19 Shielding the photocontrol from high ambient light levels COST EFFECTIVE SERVICING OF HPS LIGHTING SYSTEMS When compared to mercury vapor and metal halide lamps HPS lamps produce up to twice the amount of light per watt of power consumed In terms of lumen maintenance they outperform the other HID lamps by as much as three to one and HPS lamp life is comparable to mercury vapor as the longest available in HID lighting This all adds up to an extremely good lighting value But HPS lighting offers another great value that often is overlooked the ability to pretest and predetermine HPS lamp and luminaire performance before field installation Experience has shown that a short easy to perform lamp voltage test can help eliminate potential early failure HPS lamps and also can detect luminaires that could overdrive lamps and cause new good lamps to fail early in their rated life Spot individual lamp replacement is costly and any unusually high failure rate due to defective equipment or components can be expensive particularly when the replacements are being drawn from the same stock of lamps or luminaires that are failing in the first place The time it takes to sample test 100 luminaires and lamps usually will be less than the time it would take a service technician to drive to a defective luminaire or outage set up the bucket truck change the lamp and or luminaire and drive to the next defective lu
28. are sensitive to voltage interruptions If the lamp circuit is turned OFF a momentary power outage occurs or the lamp voltage drops below the level needed to sustain the arc discharge the ions in the arc tube deionize and light output stops The lamp will not restart immediately This is because the arc gases are now under pressure and the lamp must cool sufficiently to reduce the vapor pressure to a level where the arc will restrike at the available voltage The time required to relight is strongly influenced by the design of the luminaire since this will determine to a large extent the cooling rate of the lamp In general mercury vapor lamps will relight in 8 to 10 minutes metal halide lamps in 10 to 45 minutes and HPS lamps in 1 minute or less HID LAMP LUMEN MAINTENANCE Light output from all types of HID lamps gradually declines over time Lumen maintenance depends ona number of light loss factors These include any physical changes in the lamp such as electrode deterioration blackening of the arc tube or bulb shifts in the chemical balance of the arc metals or changes in ballast performance Longer burning cycles result in better lumen maintenance because there is less stress on lamp components due to frequent starting Other factors affecting lumen depreciation are lamp watts and current and the current waveform that is a function of the lamp and luminaire circuit Ambient temperature does not have a great effect on the maint
29. coil If the HPS starter capacitor charges to 100 volts and then discharges through the switch into the 10 turns of the ballast tap the 100 volts would be divided over the 10 turns and each turn would have 10 volts on it When the magnetic field collapses the 10 volts per tap turn would then be magnetically transferred to induce 10 volts on each of the 300 turns of the output coil This would result in a total voltage output of 3000 volts 10 volts x 300 turns 3000 volts This example is a vast oversimplification In actual transformer design other considerations must be accounted for Such as wire and core losses But the general operating principle is correct The HPS luminaire ballast also performs a number of other functions necessary in starting and operating the lamp For example the ballast allows a lower voltage to be placed on the arc tube electrodes during start up and operation of the lamp This lower voltage is the source of voltage needed to both start the lamp and then maintain and help in controlling the operation of the lamp For example HPS lamps in the 35 to 150 watt range have an initial open circuit voltage of 110 to 120 volts When the lamp starts it pulls the ballast s secondary voltage down to approximately 15 volts As the lamp warms up over the next several minutes the lamp voltage rises to its rated operating level which is usually between 44 and 62 volts Operating voltage stabilizes at this time and th
30. current limiting and voltage transformation In addition CWA ballasts are always high power factor ballasts They have starting currents that are less than the operating current In regard to voltage regulation CWA ballasts offer significant improvements over reactor and lag auto designs CWA ballasts are designed to handle a 10 line voltage variation Over this range they will maintain lamp wattage within 5 a four fold improvement over reactor and lag auto ballasts They also can handle American Electric Lighting An lt SAcuityBrands Company sudden dips in line voltage without lamp shutdown This type of ballast is most commonly used in area sports and indoor HID lighting Constant Wattage Ballasts Also called isolated regulated premium constant wattage ballasts this ballast design limits current performs voltage transformation and provides the best lamp wattage regulation available They are designed to operate over a voltage range of 13 maintaining lamp wattage to within 2 5 Constant wattage CW ballasts have a high power factor and a lower starting current than operating current These ballasts are similar in construction to CWA ballasts HPS Mag Reg Also called reg lag mag reg ballasts are used to meet HPS lamp wattage requirements on systems having a 10 voltage variation These are high power factor ballasts that have lower starting than operating current requirements The mag reg transformer consists
31. e gloves when servicing and replacing luminaires Inspect the gloves at the start Electric KE L Lighting AnSAcuityBrands Company American 10 11 12 13 14 An in depth look at the causes of the cycling ON and OFF of the HPS lamp including end of life cycling Test equipment for servicing HPS lamps and luminaires including the drawbacks of voltmeters and neon lamp luminaire testers Details on constructing and using a highly effective inexpensive piece of test equipment the incandescent lamp luminous wattmeter tester LWT Troubleshooting the HPS luminaire in the field Step by step guidelines for performing a 15 minute service call and making quick cost effective repair replace decisions Factors to consider and problems associated with the installation and use of mercury vapor to HPS conversion kits V Q NING PRO of each workday for holes and tears Replace damaged gloves immediately Keep your high voltage gloves in the glove bag located in the bucket so they will always be available when needed Always wear proper eye protection whenever you work on luminaires or replace a lamp Although not a common problem lamps have been known to shatter due to operational problems or when being turned into or out of the socket Luminaires can be heavy Position the bucket so you do not have to overreach or stretch while lifting or handling the luminaire Always secure the luminaire cover and any o
32. e lamp operates at its rated light output and color rendering capabilities See Table 1 for a complete summary of typical HPS lamp data The lower 44 to 62 volt operating voltage also keeps the HPS starter turned OFF Remember the electronic switch in the starter will close only when voltages in the neighborhood of 100 volts are applied to it Once the lamp starts and the ballast decreases voltage to the 44 to 62 volt range the electronic switch remains open and the charging and discharging of the capacitor cannot take place The 2500 to 4000 volt starting pulse can no longer be produced until the lamp is turned OFF and the initial open circuit voltage of 110 to 120 volts is applied to the starter circuit Starter Variations Since the commercial introduction of HPS lamps in the mid 1960s very few changes have taken place in the starting principles of the lamp Early starters used a transistor type electronic switch that required additional American Electric Lighting AnSAcuityBrands Company electronic components to achieve the proper timing of the switching operation Modern starter designs use a self timing device that minimizes the number of electronic components Fewer components have made modern starters more reliable Instant Restrike Starters A standard HPS lamp starter requires that the lamp cool down for approximately one 1 minute before it can be restarted Instant restrike devices that generate two to four ti
33. e resistance between the main electrodes drops to a point where the start up voltage supplied by the ballast can strike a current arc across the main electrodes The arc current continues to increase until the current rating of the lamp is reached a process that normally takes several minutes The HID arc consists of a very rapid flow of both electrons and charged arc metal ions During this rapid movement countless collisions occur between ions and electrons As these particles collide they release energy at a specific wavelength Figure 5 This energy appears to us as light Because the number of particles in the arc tube is so great and the occurrence of collisions so frequent it appears that the entire arc path constantly generates light The color of the light is a characteristic of the light spectrum wavelength of the arc metals contained in the arc tube For example in a mercury vapor lamp the mercury produces a distinct greenish white blue light Red orange and yellow hues appear grayish Mercury Atom Visible and Ultraviolet Light Electrons Starting Electrode Main Electrode Starting Resistor Ballast Line Voltage Voltage to Lamp FIGURE 5 Light production in an HID lamp American Electric Lighting AnSAcuityBrands Company Electric Discharge Through Sodium Metal End Cap Coated Tungsten Electrodes Cermaic Arc Tube FIGURE 6 Components of HID lamp designs In a metal halide l
34. eck the wiring diagram against the actual wiring to ensure the fixture has not been miswired American Electric Lighting AnSAcuityBrands Company Unknown problems If the exact nature of the problem is unknown troubleshoot the fixture as if it were an outage Cover the photocontrol and listen for a sharp click when the control operates Change the control if it growls If the lamp does not come ON substitute a known good HPS lamp If this lamp does not operate test and troubleshoot using the luminous wattmeter If the known good HPS lamp does light test for cycling problems If this is the first service call on this luminaire replace the lamp and photocontrol If it is the second call remove and replace the fixture GLOSSARY OF ELECTRICAL TERMS The following definitions are offered to develop a practical understanding of the electrical principles involved in lighting In some cases the definition may contain a slight technical error to make the definition more straightforward and convey the general meaning of the term Many electrical principles are compared to familiar mechanical actions to more clearly present an idea or concept Ballast Short Circuit Current This is current measured in the HID lamp circuit with the ballast energized and the lamp socket shorted out socket shell to socket center contact Conductor A material such as copper or aluminum that supports the flow of current It is important to remember
35. elves to the molten sealing method used in the construction of mercury vapor and metal halide arc tubes Instead PCA end caps using either a wire out end seal ora compound shrink fit and cemented end seal are epoxied or glued to the tube body using silicone glass Each tube end cap contains an electrode The sodium mercury amalgam and starting gases are placed inside the arc tube before it is sealed closed Unlike mercury vapor and metal halide lamps HPS lamps are excess amalgam lamps This means there is more sodium and mercury arc metal placed inside the tube than can be vaporized during start up and operation The amount of amalgam that vaporizes depends on the total energy in the arc and the temperature of the amalgam If the lamp becomes too hot too much amalgam will vaporize and operating voltage will increase When HPS lamps were first introduced the amalgam not held in a vaporized state remained condensed in an external reservoir located in the coolest part of the lamp If the lamp was vibrated by winds or passing traffic amalgam from the reservoir would splash down onto the arc tube causing a thermal shock that would extinguish the lamp The lamp would then go through its start up process and cycling would occur Because of this thermal blink out problem all but one of the major HPS lamp manufacturers have abandoned the external amalgam reservoir design in favor of internal reservoirs that do not create a thermal blink out
36. en very slowly uncover it in small stages to simulate sunrise You should be able to trick the cell into humming lightly as it approaches its pull in voltage If you can trick the photocontrol into growling replace it or if it is new do not use it FIGURE 16 Testing photocontrol operation By gradually exposing the cell to light by moving your hand you can trick the relay into closing A luminaire burning night and day is the most common indication of a failed photocontrol A day burner is caused by the armature contacts of the photocontrol welding together due to an electrical heat buildup from chattering relay contacts Coil circuit failure also can cause a day burner Excessive heat also can pass from the photocontrol line twist lock connector pin through the photocontrol receptacle weakening the photocontrol twist lock receptacle contacts This is a common cause of early photocontrol failure Heat also can deform the contact mounting in the photocontrol receptacle Whenever you replace or inspect the photocontrol also inspect the receptacle for signs of heat damage Look for charred or deformed plastic or other signs of damage Replace the fixture if the receptacle is damaged American Electric Lighting AnSAcuityBrands Company When installing a photocell into its receptacle make sure it is locked into position and does not pull out Make sure the receptacle mounting screws are fully tightened and holding Otherw
37. ent lamp is used because it can handle the minimum open circuit voltages of all HPS lamps except the 1000 watt HPS lamp The 50 watt lamp size produces a dimmer burning bulb that will not blind you during testing A 100 watt incandescent would be too bright The 50 watt bulb also is smaller and cooler to handle Finally the rough service grade incandescent allows for testing in luminaires where high vibration is encountered without undue breakage of the lamp filament It should be remembered however that these lamps are not indestructible Tuffskin coating for the lamp is advisable when the lamp is to be used in hazardous locations or adverse environments Be sure your luminous wattmeter is using a known good lamp before taking it into the field 23 Most HPS lamps and their corresponding luminaires are equipped with mogul bases and sockets The 250 volt 50 watt incandescent lamp only is available with a medium base The mogul to mogul extender and medium to mogul adapter are needed to properly install the luminous wattmeter into the mogul base of the HPS fixture Mogul sockets are equipped with lamp retainers and a locknut configuration that prevents the screwed in lamp from vibrating out of the lamp socket When troubleshooting it is desirable to mechanically stress the lamp socket by installing the lamp as tight as practical A light lamp base to socket contact may not reveal problems at this connection This causes some problems
38. er than 50 60 hertz IV LUMINAIRE REQUIREMENTS A Lamp Voltage Rise Limits The evacuated outer bulb of the lamp makes the lamp insensitive to ambient temperature However care must be used in luminaire design to avoid reflecting energy to the arc tube appendage always at the lower end for both base up and base down lamps This affects the temperature of the sodium mercury amalgam and results in a change in lamp characteristics The lamp voltage of new lamps 48 62 volts at 150 watts must not increase more than 4 volts when going from stabilized bare lamp operation to stabilized operation in the luminaire Fixture effects are best evaluated by operating the lamp on a linear reactor of approximately 31 ohms with the line voltage adjusted to maintain the lamp at 150 watts Additional information is available upon request Line Voltage Designation For integral ballasted luminaires labeling prominently displayed for the user should be used to indicate the range of line voltage for which the ballast is designed as published lamp ratings do not apply when the line voltage is outside these limits Minimum value required for stable lamp operation throughout life When designing the ballast consideration must be given to avoiding lamp extinction with sudden line voltage dips American Electric Lighting AnSAcuityBrands Company APPENDIX B TYPICAL LAMP MANUFACTURER S BALLAST AND LUMINAIRE REQUIREMENTS FOR 400 WATT 100 VOLT H
39. erican Electric Lighting AnSAcuityBrands Company APPENDIX A TYPICAL LAMP MANUFACTURER S BALLAST AND LUMINAIRE REQUIREMENTS FOR 150 WATT 55 VOLT HPS LAMPS This requirement is for lag circuit regulated or non regulated ballast designs I LAMP PHYSICAL CHARACTERISTICS Outer Envelope ASO gt atontatecnsswbiyatectd T voices tins Mogul Screw Elactrode BONG cores Sasossaee spaces one E23 1 2 Borosilicate Type 772 Arc Tube Maximum Overall Length cccesseeeeees 197mm Electrode Maximum Diameter 004 76 48mm 3 011 Arc Tube Amalgam Light Conter Length cccscatsevssicctmanecerntectaeess 123 3mm Support Resevoir Are Length EN 37 1mm Member Maximum Bulb Temperature arrnnnnnennnnen 400 C Maximum Base Temperature c 00008 210 C Installation Code ll LAMP ELECTRICAL CHARACTERISTICS RMS Values A Wattage PEIN I e E EEE 150 watts Permitted Operating Range for Rated Lamp Life rrrannrnnnrrnnnernnnennn Min 112 5 watts Max 175 watts B Voltage Rated Lamp Voltage Design Center rrrrrnnrrnanrenrarnrrnnnernnnnennnnrnnnnnennannnnnanennnneen 55 volts at 150 watts Initial Lamp Voltage Range at 100 HOUrs arernnnennnrvnnnrrnnrrnnnrennnrnnnnennnnennnennnnennn 48 62 volts at 150 watts Maximum Lamp Voltage JE EE NE 88 volts C Current Operating CUM EE EE EE 3 2 amperes nominal D Operating Limits The trapezoid shown below illustrates lamp v
40. g circuits ballasts and photocontrols IMPORTANCE OF SAFETY HID lamp servicing requires close attention to safety Working with electrical equipment at significant heights can be dangerous if proper preparations and precautions are not taken The following is a general safety checklist Always follow the exact safety procedures outlined by your company 1 Park the lift truck at the safest possible location at the work site Set up safety cones to direct traffic around the truck 2 Before beginning check the lift bucket of the truck to make certain it is secure The pivot point mounting should be tight with no cracks or breaks Also make certain the bucket is equipped with a fiberglass liner and that the liner is in good shape with no cracks or breaks Although not a common problem lamps have been known to shatter due to operational problems or when being turned into or out of the socket 3 Make sure the boom strap is in place and secure 4 Make certain the lanyard is in good shape fastened and secure The safety belt also must be in good condition 5 Always strap on the safety belt before raising the bucket Putting the safety belt on should be the first thing you do after stepping into the bucket 6 Always use a properly secured safety belt when working from ladders 7 Always wear a hard hat when servicing a luminaire in the field 8 Wear work boots with non slip insulating soles 9 Always wear high voltag
41. he high voltage pulse its voltage reading only will indicate that voltage is present It cannot determine the load carrying capability of the circuit being checked For example if the screw to the center contact of the socket becomes loose the HPS light bulb may not light when screwed into the socket However if the leads of the voltmeter were placed across this connection the meter would read voltage A low grade connection may allow the voltmeter to read a voltage but limit the current to levels below those needed to operate the lamp Neon Lamp Testers Various luminaire and lamp manufacturers also sell special neon testers designed to troubleshoot and test HPS systems These testers may use from one to three neon lamps The single neon lamp type usually indicates socket voltage or spike voltage The two and three neon lamp testers are designed to indicate the presence of both socket voltage and spike voltage The two lamp tester indicates a spike on one half cycle only while the three lamp tester supposedly indicates a spike voltage on both half cycles of the AC waveform Using these testers can be confusing and results are not always accurate For example the neon can be lit by stray voltages from various sources such as high voltage transmission lines transformers and other American Electric Lighting AnSAcuityBrands Company devices emitting static voltage And like a voltmeter a neon tester even when operating co
42. hort duration and very low current The incandescent lamp harmlessly shorts out this starter output The luminous wattmeter has been used to troubleshoot luminaires equipped with instant restrike devices producing 12 000 to 14 000 restrike voltage pulses or spikes with no harm to the incandescent bulb Caution Always wear safely glasses when working with light bulbs of any type because there is always a possibility of a freak situation that may cause the lamp to explode American Electric Lighting AnSAcuityBrands Company Mercury Vapor Test Lamp Since a mercury vapor lamp does not require a starter it too can be used to troubleshoot an HPS luminaire although not as effectively as an incandescent lamp A mercury vapor lamp requires 240 volts at the socket for starting HPS luminaires designed for 35 to 150 watt 55 volt HPS lamps only will provide 120 volts In this case the mercury vapor lamp may start with 120 volts provided the ambient temperature is not too cold Unlike an incandescent luminous wattmeter a mercury vapor test lamp will not readily show varying degrees of brightness They also cannot be made to flicker when checking for intermittent connections Instead the mercury vapor lamp will drop out and cycle For these reasons it is highly recommended you use an incandescent luminous wattmeter to troubleshoot HPS fixtures SERVICING HPS LUMINAIRES AT AN INSTALLED LOCATION After reaching a defective HPS luminaire
43. ibration or movement induced problem that occurs in HPS lamps Thermal blink out is most common in exterior reservoir lamps operated in a position that places the amalgam reservoir above horizontal in the light fixture However severe vibration problems can cause thermal cycling in all types of HPS lamps Vibration or movement due to wind traffic or other reasons can cause excess amalgam to splash down onto the white hot electrode giving ita thermal shock This thermal shock causes the lamp to drop out and cycle Bridge and viaduct installations are prone to thermal cycling problems Thermal cycling can be avoided by selecting nonexternal reservoir type lamps for high vibration applications In severe vibration conditions thermal cycling could be fixture related You can test for thermal cycling using the bump test Photocontrol Induced Cycling An overly sensitive photocontrol unit may cause cycling in an HPS or HID lamp installation Light from the luminaire or from other light sources around it can trick the photocontrol causing it to turn OFF the luminaire Aim the photocontrol away from strong light sources or install shields to cut down on the level of ambient light entering the photocell Figure 19 Seasonal changes can cause cycling problems due to reflective light differences between green leaves in spring and summer and dead leaves and exposed tree bark in fall and winter American Electric Lighting AnSAcuityBr
44. id shown below illustrates lamp voltage wattage limits For a ballast to meet the lamp operat ing requirements its characteristic curve must intersect each of the lamp voltage limit lines at points between the wattage limit lines and must remain between these wattage limit lines throughout the full range of lamp voltage 450 400 350 LAMP WATTS 1 Lamp voltage is determined after operating the lamp on a linear inductor for one hour The line voltage is adjusted to control the lamp wattage The lamp characteristic curve is the volt watt curve for the equilibrated lamp The characteristic voltage is the lamp 300 voltage at rated watts NO Lamp characteristic voltage may rise reaching 140 volts near the end of life 60 80 100 120 140 160 LAMP VOLTS TRAPEZOID 400W HPS 100V Lamp American Electric Lighting AnSAcuityBrands Company 180 31 Ill BALLAST REQUIREMENTS 32 The required ballast characteristics must be provided with the ballast operating over the full range of line voltage for which it is designed A Minimum Ballast Open Circuit Voltage O C V 195 Volts RMS This is the minimum value required for stable lamp operation throughout life When designing the ballast O C V consideration must be given to avoid lamp extinction with sudden line voltage dips A ballast lamp testing procedure measurement of ballast drop out point for High Pressure Sodium ballasts is available from the OEM fixt
45. in electrodes American Electric Lighting AnSAcuityBrands Company The starter is used only during the first few moments of lamp start up Once the starting gas arc is struck between the main electrodes the starter turns OFF and does not operate until it is needed again Many service technicians unfamiliar with HPS starter operations are unaware of this fact They automatically replace the starter when faced with an HPS lamp that cycles ON and OFF particularly if the cycling is intermittent The technician assumes the starter is at fault In fact it is operating repeatedly it is turning the lamp ON not once but many times The external starter must be properly matched to the lamp luminaire and ballast There are slight design and operating differences between starter manufacturers and mixing starters could result in unreliable starts There also are differences in the various wattage match ups provided by the fixture manufacturers Therefore mixing various wattage ballasts with various starting circuits is not recommended as this also could result in unreliable starting Starter Operation An HPS starter operates similarly to an automotive breaker point ignition system The ignition system is made of two interconnected circuits the primary low voltage circuit and the secondary high voltage circuit When the ignition switch is turned ON current flows to the ignition coil s primary winding through the breaker point
46. ing the cycling such as wind traffic induced vibration or a slight variance in line voltage are not occurring at the moment If the lamp is no longer cycling use the bump test described earlier to induce a vibration in the lamp and luminaire With metal poles it is possible to sufficiently shock the fixture by striking the pole while standing on the ground When wood or concrete poles are used it may be necessary to moderately strike the fixture mast arm 26 If the lamp in question has reached its normal end of life this bump test will cause the burning lamp to turn OFF Reinstall a known good lamp and allow it to warm up for several minutes Reshock the lamp If it turns OFF check the fixture wiring by probing with an insulated tool to locate opens and shorts Check that the ballast and capacitor match the lamp rating and be sure the capacitor is correctly wired If this fails to isolate the problem replace the luminaire If the vibration test of the suspect lamp does not cause it to cycle turn the photocontrol to the area where it will receive the least amount of ambient light Since a fixture s own light can sometimes reflect off of an object such as a tree or building and cause the fixture to turn OFF and then ON again after the lamp has cooled be aware of nearby reflective surfaces and shield the photocontrol if necessary Also be sure the lamp is the correct lamp for the fixture by checking the lamp inscription label
47. ise the springy nature of the gasket used to seal the photocell mounting surface will push the photocell upward and it will not be seated properly in its receptacle Any vibration also will help push an improperly mounted photocell off its contacts The contacts will then arc and burn causing heat damage as just described HPS LAMP CYCLING All HPS lamps experience voltage rise during their life and have a designed end of life voltage rating When the voltage rise reaches the end of life voltage the ballast cannot supply the needed operating voltage the lamp goes out and cycling begins As the hot lamp cools it restarts at a lower than end of life voltage But as the lamp begins to heat up again its operating voltage soon rises past its end of life voltage The lamp turns OFF and the cycle repeats itself End of life cycling can occur in an HPS lamp at the time of installation at six years at end of life or at any time in between A bad lamp can fail prematurely In most cases cycling is caused by a voltage rise due to increased lamp resistance electrode wear etc Equipment Mismatching Using the wrong lamp in the fixture Figure 17 can cause cycling As shown in Table 1 150 watt HPS lamps are manufactured in two voltage ratings 55 volts and 100 volts HPS 150 watt lamps will have their voltage rating stamped on the lamp body to avoid confusion when replacing these lamps A 150 watt 100 volt HPS lamp installed in a 150 watt
48. itch of the starter is activated by the rise and fall of the voltage levels that occur in the 60 cycle alternating current AC used to power the lighting fixture AS you can see from the 120 volt AC waveform shown in Figure 10 the voltage cycles from 0 to 177 volts to 0 to 177 volts again 60 times per second The average voltage is 120 volts As the voltage rises and falls in each half cycle the electronic switch opens and closes just as the breaker points in the automotive distributor open and close when the distributor camshaft is rotated Max Voltage177 V Switch Closes Switch Opens Max Voltage Approximately 100V 177V Switch Closes Switch Opens sh Time 1 60 Second FIGURE 10 The electronic switch in the starter circuit closes every time voltage of 60 cycle AC power source rises above a certain level 12 The capacitor also plays an important role in the operation of the starter When the light fixture is turned ON the capacitor is charged by the rise in voltage in the 60 cycle AC When the voltage rises to the upper portion of the generated half cycle the voltage level reaches a point that causes the electronic switch to close Once the electronic switch closes the charged Capacitor is given a discharge path to the 10 to 12 winding turns of the tapped portion of the ballast Figure 11 The ballast tap acts as a primary coil The high voltage step up in the ballast is accomplished in much the same
49. layed for the user should be used to indicate the range of line voltage for which the ballast is designed as published lamp ratings do not apply when the line voltage is outside these limits American Electric Lighting AnSAcuityBrands Company V SOCKET REQUIREMENTS A Breakdown Voltage The internal clearances of typical mogul sockets are such that if an arc over occurs a destructive power arc will be sustained by ballasts meeting the criteria stated below For this reason the internal breakdown voltage of the socket should provide an adequate margin of safety under the environmental conditions anticipated This can be measured by applying a 50 to 60 Hz sinusoidal voltage wave form between the center pin and shell terminations of the socket with a dummy 400 watt High Pressure Sodium ceramic base inserted The voltage should be increased from zero at a rate of no more than 4kv min until breakdown occurs The peak voltage at the point of breakdown should be 7kv This test is equivalent to a 5000 volt RMS high pot test Perform the test on the socket separately American Electric Lighting AnSAcuityBrands Company American American Electric Lighting Electric Acuity Lighting Group Inc Lighting 1335 Industrial Boulevard Conyers GA 30012 Phone 800 754 0463 Fax 770 860 3255 2004 Acuity Lighting Group Inc 10 04 AEL6022 pmd Form No 1315 29 MA dg JE An SAcuityBrands Company
50. lectrodes As the two ends of the arc tube are heated and pressed together the two main electrodes and thinner starting electrode are imbedded in the molten glass The arc metal and starting gas are fed into the tube through a glass straw welded into the arc tube As the glass straw is heated to the melting point the opening seals trapping the gas and arc metal inside Both mercury vapor and metal halide arc tubes are filled with the exact amount of arc metal commonly called amalgam needed for operation After an initial 100 hour burn in time by the end user mercury vapor and metal halide lamps reach a stabilized operating point at which all arc metal inside the tube is ionized during start up and operation At this point lamp voltage becomes relatively constant throughout the rest of the lamp s operating life There is a very slight voltage rise but it is not great enough to affect the life span of the lamp The same is not true of HPS lamps The arc tube of an HPS lamp is a slender cylinder approximately 1 4 to 3 8 in diameter Sodium cannot be contained in a glass tube The sodium would etch the glass and further degrade light output Sodium must be contained in a metal container Most lamp manufacturers use a special ceramic material known as polycrystalline alumina PCA to construct the HPS arc tube PCA is basically an aluminum oxide material virtually insensitive to sodium attack PCA tube materials do not lend thems
51. mercury ballast X X HPS X X X X HPS no starting circuit mercury ballasted X X Low Pressure Sodium x NOTE X indicates equipment that is normally appropriate for a given source Capacitor required for high power factor only All voltages Specially designed CWA type ballast for metal additive lamps Ballast Characteristics Typical characteristics of ballasts used in HID lighting systems are summarized in Table 2 Figure 13 illustrates luminaire wiring diagrams for the various ballasts used in HID lighting systems Other characteristics are as follows Ballast Efficiency No ballast delivers all of the current passing through it to the lamp it serves Some power always is lost in the form of resistance heat A ballast that is 90 efficient delivers 90 of the power to the lamp The remaining 10 is wasted in heating the ballast The ballast watt losses add to the total power consumed Line Voltage For some ballasts the line voltage as the lamp starts is less than the final operating voltage In these cases fuses and circuit breaker ratings should be based on the operating voltage value For other ballasts the starting voltage is considerably higher than the final operating voltage so circuit protection must be sized to accommodate starting voltage levels Line Voltage Regulation Variations in line voltage can be caused by system demands and other factors Newer power systems normally opera
52. mes the normal maximum pulse voltage are available This voltage is strong enough to overcome the gas pressure inside the arc tube and instantly reionize the gases restarting the lamp Instant restart devices usually are required in industrial applications where safety rules require the restoration of light within a short period of time after a power outage has occurred Instant restrike starters are more expensive than standard starters Two Lead Starters One recent innovation in HPS starter technology is the two lead starter Figure 12 This HPS lamp starter contains its own ignition coil and does not rely on the ballast to provide voltage step up Some two lead starters can be used with any manufacturer s ballasts In contrast starters that use the ballast as an ignition coil are not readily interchangeable The reason for this is that the turns ratio between the ballast tap and the output coil portion of the ballast varies from one manufacturer to another This coupled with differences in electronic component values between manufacturers can lead to mismatch problems Anew lamp usually will start with a mismatched starter and ballast but significantly reduced lamp life or premature ballast failure is likely Limited lamp life can occur when the mismatch does not allow the proper starting pulse to be produced If the starting voltage pulse exceeds the lamp manufacturer s limits the arc tube electrodes will erode away Causing
53. minaire lamp location Test Procedures An HPS lamp can be pretested due to its voltage rise during its lifetime For example a new 100 watt HPS lamp is nominally rated at 55 volts with an operating voltage range of 45 to 62 volts This operating voltage usually stabilizes within 10 to 15 minutes after start up The 100 watt HPS lamp has an end of life voltage of 84 volts 21 The projected life of the 100 watt HPS lamp is based on a lamp voltage rise from the 45 to 62 volt range to the 84 volt end of life voltage This slow voltage rise usually takes about six years of normal operation However if a new HPS lamp tests higher than this 45 to 62 volt operating range in the neighborhood of 70 volts for example experience has shown that the rate of voltage increase will be significantly higher The lamp will have a dramatically reduced life and is a likely candidate for spot replacement if installed in the field Note The above voltages are based on an ANSI standard where a nominal ballast is used on its nominal design voltage Experience has shown that a slight 2 or 3 volt variation out of this range has not been detrimental to lamp life For example a lamp rated at 45 to 62 volts will operate satisfactorily in the 42 to 65 volt range Selecting the Test Group In most cases testing of 5 to 7 of the lamp or luminaire inventory is sufficient when testing for possible defective lamp or luminaire batches or runs However 1
54. n lamp wattage Lamp life generally is much shorter than HPS and mercury vapor due to poorer lumen maintenance and the presence of iodine compounds in the arc tube The normal failure mode is the inability to start because of increased starting voltage requirements Frequent starting also will adversely affect lamp life as will overwattage operation THE HPS LUMINAIRE Troubleshooting and repairing HPS lighting fixtures involve working with some components and operating principles not found in mercury vapor or metal halide fixtures Now that you understand the primary differences between HPS mercury vapor and metal halide operation it s time to discuss how these differences affect troubleshooting and repairing procedures HPS Lamp Starters Inspection of an HPS luminaire will reveal an additional component not found in mercury vapor or metal halide fixtures an external starter Figure 9 This starter can be found as a printed electronic circuit board in some luminaires The starter also may be packaged in a Small plastic cube or can Regardless of how they are packaged external starters all perform the same function they increase the 120 or 240 volts supplied to the lamp to the 2500 to 4000 volts needed to start the lamp Note 1000 watt HPS lamps require a minimum starting voltage of 3000 volts and a maximum of 5000 volts As explained earlier this high voltage spike is needed to bridge the wide gap between the HPS lamp s ma
55. n the known good HPS lamp is installed in such a situation it will not start When installed in its place the luminous wattmeter also will not light When this condition occurs leave the luminous wattmeter in the luminaire until it is made to burn For example repairing the bad connection would allow the luminous wattmeter to light Then it could be assumed the cause of the problem was the bad connection but when the known good HPS lamp is reinstalled it does not start Once reaching this point in the troubleshooting procedure it becomes apparent that two problems exist The fact that you were able to make the luminous wattmeter burn but not the HPS lamp indicates a possible defective starter The important fact to remember is to leave the luminous wattmeter installed until it burns Attempting to find intermittent connections and starter related problems by only an HPS lamp could lead to considerable confusion and wasted time Special Problems In rare cases a luminaire ballast or capacitor failure may allow the luminous wattmeter to burn but not allow the HPS lamp to ignite and operate even when a known good starter is installed However this is a very rare situation that most service technicians never will encounter Voltage Pulse Concerns There is no need to be concerned over the possibility of the 2500 to 4000 volt starting pulse voltage spike damaging the luminous wattmeter or causing it to explode The spike is of very s
56. nical inspection are now ready for electrical testing HPS lamps photocontrols and luminaires can be pretested in one of three ways 1 By using atest group of sample lamps and luminaires 2 By testing lamps and luminaires using a special HPS lamp luminaire test bench 3 By testing photocontrols using the test bench American Electric Lighting AnSAcuityBrands Company TESTING HPS SYSTEMS IN THE FIELD The high voltage spike required to start an HPS lamp makes electrical testing of the luminaire somewhat of a problem Testing for this very short duration voltage pulse normally would require the use of an oscilloscope But an oscilloscope is not a practical piece of test equipment when testing a luminaire in the field The quality and cost of the scope needed to accurately display this voltage pulse is quite high Even when accurately displayed the short duration spike Is very hard to see on the scope screen particularly in daylight or bright sun Plus the oscilloscope is difficult to maneuver and set up in a truck bucket and impossible to use from a stepladder or from climber s hooks Voltmeters Voltmeters are of limited use when troubleshooting HPS luminaires They can be used to check minimum open circuit voltage at the lamp but only after the starting circuit lead has been disconnected Otherwise the extremely high starting pulse voltage could damage the voltmeter Even if the voltmeter is protected against t
57. nn 25 HPS Luminaire Failures rrrnrrnarrnnnrrrnnervnnennn 26 GLOSSARY OF ELECTRICAL TERMS 27 APPENDIX A oct csasicnnousncaesesceertatesscceacticteeceddachsuneroiaes 29 Lamp Physical Characteristics 000 29 Il Lamp Electrical Characteristics RMS Values rrranonnnnrnnnennnnennnnnnanennnnennnene 29 III Ballast Requirements cccccssccseeeeees 30 APPENDIX Been 31 Lamp Physical Characteristics 00 31 Il Lamp Electrical Characteristics RMS Values cncetesciesacneauecenscseticcdencoscntesteoess 31 IIl Ballast Requirements rrrrnnnrnnnrrnnrnnnrnnnennrr 32 IV Luminaire Requirements r arrnnnrnnnrnnnrnnnrn 32 V Socket Requirements rrrnnnrnannnvanernnnrnnnere 33 American Electric Lighting An SAcuityBrands Company OVERVIEW The information presented in the High Pressure Sodium HPS Servicing Guide is generic in nature It can be applied to and used in troubleshooting and servicing all types of HPS systems regardless of the manufacturer The servicing guide contains information illustrations and data on these same topics e Safety practices and equipment used when servicing HPS and other High Intensity Discharge HID lighting systems e Basic construction and operation of HID lamps and how they differ from incandescent lamps e Unique construction and operating features affecting servicing Special attention is paid to startin
58. nnnnennnnevannnnnnennnnnn 18 HID LAMP BALLASTS 1 errnrranrorrarnrvnerernnnnennnnennnnnen 14 TABLE 2 Characteristics for HID Light Sources 16 Ballast Characteristics cccccccseeeseeeeseeeeees 16 Reactor Ballasts ccccscccsceceeeceeeeeeeeeesaeees 16 Lag Auto Ballasts srswicssvscasionsdenvcveumdsesieuleneueeex 16 Constant Wattage Autotransformer Ballasts 17 Constant Wattage Ballasts orrrrnnnrrrnnronnnrre 17 HPS Mag Reg sas asaiauisiexsssieescnssancaetenbereecaceternuesd 17 Matching Lamp and Ballasts arerrnrernnrrnnrernn 18 PHOTOCONTROL OPERATION AND TROUBLESHOOTING scccsscscssadercsscrnederceesnceenedseese 18 HPS LAMP CYCLING sassanidene 19 Equipment Mismatching ccssceseeeeeeeeeees 19 Reignition Phenomenon arrvnnrevnnrvnerevnvennenenne 20 Vibration Sensitivity rrrrrrnnnnrrrnnnnrnrnnnrnvnnnennnn 20 Thermal Cycling ctccctndssacteassatdbicdcncessnsstedsuamenteds 21 Photocontrol Induced Cycling cccceeee 21 COST EFFECTIVE SERVICING OF HPS LIGHTING SYSTEMS ccsseccusscccticrsstacccicsocsnince 21 Test Procedures sansene 21 Selecting the Test Group ccsseceeeeseeeeeeeees 22 VEIS NO 22 TESTING HPS SYSTEMS IN THE FIELD 0 0 0000 23 VE 23 Neon Lamp Testers cccccseceeeceeeseeeseeeees 23 Luminous Wattmeters rrarrnnnrnnrrnnrrnnrnvnrnnnnnnn 23 SERVICING HPS LUMINAIRES AT AN INSTALLED LOCATION rnunnnnnnnnnnennnnnvvnnnnenn
59. ocontrol or photocell as it is sometimes called consists of a small cadmium sulfide cell wired in series with an electrical relay Figure 15 Keep in mind that the cadmium sulfide cell is not an energy producing cell It does not convert the sun s energy into a voltage 18 To Power Line Armature and Contacts Photocell Neutral To Line Neutral FIGURE 15 Photocontrol components and circuit The cell is a variable resistor similar to those used to turn the volume of a radio up or down The amount of light that strikes the cell increases or decreases the amount of electrical resistance in the cell During the day when light strikes the photocell resistance in the cell is very low Current from the service drop can flow through the cell to the coil of the photocontrol relay When the coil is energized it creates a magnetic field that pulls in the armature of the relay This armature movement opens the contacts to the fixture ballast The lamp cannot operate with no line voltage supplied to the ballast As darkness falls less and less light strikes the photocell and electrical resistance in the cell begins to increase Less and less current passes through the relay coil and strength of the magnetic field generated by the coil drops Finally the magnetic field becomes so weak that it cannot hold in the armature and the armature moves over to its open position When the relay armature is in its open position
60. oltage wattage limits For a ballast to meet the lamp operating requirements its characteristic curve must intersect each of the lamp voltage limit lines at points between the wattage limit lines and must remain between these wattage limit lines throughout the full range of the lamp voltage Maximum temperatures allowed under conditions where published performance ratings apply Lamp voltage is determined by operating the lamp on a linear inductor of approximately 31 ohms for one hour with the line voltage adjusted to maintain the lamp at 150 watts Lamp voltage may rise reaching 88 volts near the end of life 180 O oO LAMP WATTS z lt N O 30 40 50 60 70 80 90 100 TRAPEZOID 150W HPS 55V Lamp American Electric Lighting 20 An lt SAcuityBrands Company Ill BALLAST REQUIREMENTS The required ballast characteristics must be provided with the ballast operating over the full range of line voltage for which it is designed A Minimum Ballast Open Circuit Voltage O C V 110 Volts RMS B Starting Pulse Requirements 1 Pulse peak voltage Min 2500 volts Arc over in the lamp structure will not occur at peak voltage less than 4 000 volts 2 Pulse width measured at 2250 volts Min 1 microsecond 3 Pulse repetition rate Min 50 per second 4 Pulse peak current Min 0 2 amp 5 The starting pulse should be located within 20 electrical degrees of the peak of the open circuit voltage for the mo
61. rcury Vapor Lamps The graph in Figure 7B covers the lumen depreciation curves for a range of mercury vapor lamp wattages Maintenance of most types falls in the darkly shaded area Frequent starting or lamp burning position has very little effect on mercury vapor lumen maintenance Metal Halide Lamps As the graph in Figure 7C shows the light output of metal halide lamps declines more rapidly than either HPS or mercury vapor lamps Frequent starting will shorten metal halide lamp life Approximate Lumen Maintenance of HPS Lamps Initial Lumens Percent Initial Lumens Percent gt o 4 8 Hours Burned Thousands Approximate Lumen Maintenance of Mercury Vapor Lamps Hours Burned Thousands HID LAMP LIFE The rated average life of HID lamps is the life obtained from a large group of test lamps burned under controlled conditions at 10 or more burning hours per start It is based on the survival of at least 50 of the lamps or groups of lamps and can vary considerably from the average Factors affecting HID lamp life include lamp operating wattage lamp operating temperature ballast characteristics line voltage and burning hours per start Lamp age or the number of hours a lamp has operated has very little effect on lamp startability although metal halide lamps can require longer starting times as they age HPS Lamps As shown in the lamp survival curve in Figure 8A HPS lamps have a long average life span of 24
62. resistance to current flow This controls the amount of current passing through the lamp On the other hand HID lamps are amps dumb They have no built in resistance to current flow and the lamp must rely on an external ballast to limit current flow to the lamp The wattage and voltage ratings of the HID lamp and its ballast must match exactly Fluorescent Lamps Fluorescent lamps are low pressure or Low Intensity Discharge lamps The lamp consists of a closed tube that contains two cathodes an inert gas such as argon and a small amount of mercury Figure 2 When voltage is supplied to the lamp in the correct amount an electrical arc strikes between the two cathodes This arc emits energy that the phosphor coating on the lamp tube converts into usable light HID Lamps The HID lamp group is by far the most important lamp group used in modern exterior and industrial lighting HID light sources are highly regarded for their long life and high efficacy The compactness of HID lamps also increases optical control and allows for a great deal of flexibility in the area of luminaire design HID systems are the most cost effective method of lighting roadways parking areas sports fields signs and buildings HID systems also are ideally suited for interior applications such as sports arenas warehouses industrial plants and certain types of indirect office and commercial lighting Exhaust Lead In Phosphor Coating FIGUR
63. rrectly indicates only the presence of a voltage It cannot tell you if the circuit being tested has a load carrying capability The circuit being tested could have poor or marginal connections Also some HPS lamp starters are designed to produce a starting spike on only one of the two AC current half cycles Others are designed to produce spikes on both half cycles A single luminaire manufacturer may use both systems and there are no markings on the luminaire to indicate which system is being used This means that if you test a one half cycle starter with a three neon lamp tester designed to signal the presence of spikes on both half cycles the tester automatically would indicate a defective starter There also are several specifications that must be met in the starting voltage spike The spike must be between the 2500 to 4000 volt ranges It must be within 20 electrical degrees of the center of the half cycle point and its duration must be from 1 to 15 microseconds at 2150 volts The neon tester does not indicate the spike s conformity to any of these parameters Luminous Wattmeters One of the most reliable meaningful and economical pieces of test equipment for HPS lamps is the incandescent lamp A simple luminous wattmeter can be made using a 250 volt 50 watt rough service incandescent lamp equipped with a mogul to mogul lamp socket extender and fitted with a medium to mogul socket adapter Figure 25 A 250 volt incandesc
64. rstand how HID lighting systems operate a short review of incandescent and fluorescent lamp operation is helpful Incandescent Lamps A conventional tungsten incandescent lamp has a tungsten filament enclosed in a glass bulb filled with inert gases Figure 1 When electric current is passed through the filament it offers resistance to the current flow The filament heats up and glows producing light As the lamp operates the tungsten filament evaporates and deposits as black patches on the inside of the bulb The inert gases work to reduce this blackening but cannot eliminate it Light output diminishes as the filament evaporates and the lamp eventually fails due to filament breakage Tungsten halogen lamps try to reduce filament evaporation by including small amounts of bromine forcing the tungsten to redeposit on the filament Halogen lamp life is about twice that of conventional incandescent lamps Incandescent lamps are available in wattages ranging from 2 to 1500 watts and above In many cases the light level generated by a particular luminaire can be increased or decreased simply by switching to different lamp wattage Tungsten Glass Bulb Filament Inert Gas Lead in Wire Heat Deflection Stem Disc Press F s Exhaust Tube FIGURE 1 Typical incandescent lamp components This is because incandescent lamps are resistance smart The lamp s filament is designed and sized to offer a preset amount of
65. s to ground This low voltage current flow in the coil s primary winding creates a magnetic field When the current flow is interrupted as the breaker points open the magnetic field collapses and a high voltage surge is induced in the coil s secondary winding FIGURE 9 Starter circuit in typical HPS circuit 11 The high voltage surge from the secondary coil windings flows to the distributor via an ignition cable From the distributor high voltage is delivered through cables to the individual spark plugs where it arcs across the plug electrodes to ignite the air fuel mixture in the cylinder Opening and closing the points acts as a switch Timing of the open close switching is controlled by a camshaft in the distributor As the camshaft turns lobes on the shaft open and close the points A condenser which is actually a capacitor promotes fast and complete breakdown of the magnetic field in the primary coil This helps produce a strong induced voltage in the secondary coil An HPS lamp starter contains corresponding components An electronic switch acts in place of the mechanical breaker points of the ignition system The starter circuit contains a capacitor that corresponds to the ignition system condenser The HPS ballast acts as the ignition system s primary and secondary coils The electrodes in the arc tube correspond to the spark plug electrodes and the starting gas acts as the combustible fuel The electronic sw
66. s effective life will be over HID OPERATING CHARACTERISTICS Certain operational characteristics are common to all HID lamps With any HID lamp sufficient starting current must be supplied to the lamp during the first half minute or so of operation Too little current results in the lamp never warming up properly while too much current will reduce lamp life Too little current can be caused by an improperly installed lamp a bad connection or a bad capacitor or use of the incorrect ballast or capacitor Due to manufacturing tolerances individual HID lamps operate within a range of operating voltages For example as shown in Table 1 a 150 watt HPS lamp rated at 55 volts can have a lamp voltage range of 48 to 62 volts HID lamps will operate at their rated wattages only if the lamp and line voltages are nominal Variations in lamp and line voltages can cause a lamp wattage variation of up to 20 American Electric Lighting AnSAcuityBrands Company HID lamps should not be operated at higher than rated wattages This can be caused by using a capacitor with a rating too high for the fixture or by installing a lamp with a lower wattage rating than the fixture Although light output may increase the excess wattage dramatically increases operating temperatures of electrodes arc tubes and bulb walls The arc tube may bulge and possibly shatter Lumen maintenance and lamp life also are significantly decreased HID lamps also
67. s would be needed to operate an ordinary incandescent lamp with the same wattage rating Normal power factor ballasts are commonly used in reactor and high reactance type ballast circuits for both mercury vapor and HPS lamps They commonly are used for lower wattage lamps of 150 watts or less A high power factor ballast is one that draws within 10 of the minimum line voltage for a specific power consumption This type of ballast is described as having a power factor of 90 or greater High power factor ballasts allow the use American Electric Lighting AnSAcuityBrands Company of a large number of luminaires and high wattage lamps on each branch circuit The total power in any direct current DC circuit or in any AC circuit with only resistance loads such as incandescent filament lamps is expressed by the fundamental equation Total Watts Volts x Amperes In such circuits the total watts are active in doing useful work such as producing light In an HID lamp circuit that requires a ballast some of the current is not effective in operating the ballast or in producing light So in an HID circuit the product of volts and amperes does not equal the active watts as read by a wattmeter because such a meter measures only the active power used It is therefore necessary to express the active watts in an HID lamp circuit as follows Total Watts Volts x Amperes x Power Factor Active Total Watts Active Amperes
68. several minutes after start up Changes that affect the temperature of the arc tube such as changes in the voltage supplied to the lamp through the ballast can produce significant variations in the lamp s wattage and light output Ballasts act to reduce this variation by absorbing part of this varying voltage input By subjecting the steel core of the ballast to high amounts of magnetic force you also can change the ratio at which voltage is transferred between its primary and secondary coils For example a ballast can be designed to have a given voltage transfer ratio at a predetermined input voltage However if input voltage begins to increase from this value the steel core of the ballast becomes overworked or saturated by magnetic force The result is that increases in voltage in the primary coil are not transferred to the secondary coil nor are they passed on to the lamp Instead the ballast continues to output voltage at the proper levels This is the basic design principle used in all regulated ballasts The secondary or lamp is isolated from changes in the primary or power supply Compensating for the low power factor characteristic of the arc discharge Ballasts are classified as either normal or high power factor A normal power factor ballast and HID lamp combination has a power factor of approximately 50 This means that for a given wattage more than twice as much current is required to operate the HID lamp and ballast a
69. st against unusual lamp failure modes the ballast should be capable of operation with an open or short circuit condition for extended periods Other Considerations 1 High Pressure Sodium lamps like other discharge lamps exhibit reignition phenomena that are influenced by ballast design Certain ballast designs can lead to distinctive effects such as a Strong visual lamp flicker b High lamp reiginition voltage c Lamp extinction and or unusual sensitivity to line voltage fluctuations d Pulse voltage required to start lamps in excess of the minimum starting pulse requirements Section 3B NOTE Any such observations should be cause for concern as the system life and performance may be adversely affected 2 Published lamp performance ratings apply only when High Pressure Sodium lamps are operated on 50 60 hertz IV LUMINAIRE REQUIREMENTS A Lamp Voltage Rise Limits The evacuated outer bulb of the lamp makes the lamp insensitive to ambient temperature However care must be used in luminaire design to avoid reflecting energy on the arc tube appendages This affects the sodium mercury amalgam and results in a change in lamp characteristics The lamp voltage of new lamps 90 115 volts at 400 watts must not increase more than 10 volts when going from stabilized bare lamp operation to stabilized operation in the luminaire Line Voltage Designation For integral ballasted luminaires labeling prominently disp
70. st reliable lamp starting 6 Lamp starting is not affected by ambient temperature C Lamp Current During Warm Up Min 3 2 amp RMS Max 4 8 amp RMS D Maximum Current Crest Factor 1 8 E Ballast Marking The ballast should be clearly labeled to indicate the range of line voltage for which it is designed as published lamp performance ratings do not apply when the line voltage is outside these limits F Short Circuit and Open Circuit Current To protect the ballast against unusual lamp failure modes the ballast should be capable of operation under either an open or short circuited condition for extended periods NOTE Starting pulses are not required and are not desirable after a stable arc has been established 30 G Other Considerations 1 High Pressure Sodium lamps like other discharge lamps exhibit reignition phenomena that are influenced by ballast design Certain ballast designs can lead to distinctive effects such as a Strong visual lamp flicker b High lamp reiginition voltage c Lamp extinction and or unusual sensitivity to line voltage fluctuations d Pulse voltage required to start lamps in excess of the minimum starting pulse requirements NOTE Any such observations should be cause for concern as the system life and performance may be adversely affected 2 Published lamp performance ratings do not apply when High Pressure Sodium lamps are operated on direct current or at frequencies oth
71. t includes the glass bulb arc tube screw base etc It should not be confused with the luminaire see below The lamp is commonly referred to as the light bulb Luminaire The complete lighting unit Its metal housing contains the lamp socket wiring starter ballast photocontrol receptacle optical assembly and all other components needed to generate lumen output Many times the luminaire simply is referred to as the fixture Ohm s Law The basic law of electricity It states that Voltage Current x Resistance This equation can be used to find any unknown variable when the other two variables are known Open Circuit A break or disconnection in the wiring or at a connection Current does not flow in an open circuit It is commonly expressed as voltage measured at the lamp socket without a lamp in the socket Power The rate at which electrical energy is used The watt is the unit of power measurement Power requires voltage and current that is electric pressure accompanied by a flow of electrons Power can be calculated using the following equation Power Voltage x Current Wattage results in heat and light Power Factor The time difference between the presence of voltage and the flow of current It can be compared to air in the water line of a pumping system You turn on the faucet and there is pressure voltage but a burst of air is all that comes out before the water current begins to flow Power factor is high 90
72. te within 5 of the rated system voltage but in some older systems the daily voltage variation can be as high as 10 The ballast selected must be able to accommodate these voltage fluctuations Extinction Voltage All power systems are subject to dips in line voltage that normally are around 10 but 16 occasionally can reach 20 to 30 The ballast should be capable of riding out these dips without extinguishing the lamp Reactor Ballasts Reactors are the simplest type of ballast They consist of a single coil or wire on a core of steel Functionally they act as current limiters and provide some lamp wattage regulation Reactors are normal power factor ballasts but a capacitor can be added to provide high power factor performance The units are designed for 5 input voltage variation and limit or regulate lamp wattage to a 12 variation within that range For example in a 240 volt 400 watt reactor ballast voltage can vary from 228 to 252 volts 45 and wattage from 352 to 448 watts 12 Characteristically reactor ballasts require a higher start up current than operating current They only are used when the available line voltage is at least two times greater than the lamp rated operating voltage An HPS reactor ballast contains a starting circuit that provides the proper pulse voltage for starting the lamp Lag Auto Ballasts This type of ballast is known by several names lag auto lag or high reactance ballast
73. tely The lamp socket center contact and the tip of the lamp base must be in proper contact when the lamp is installed If the center contact and lamp tip become misaligned due to a mismatch between the socket contact and the lamp tip the lamp may not start due to poor or partial contact between the two If this problem occurs some service technicians may try turning the lamp out 1 2 turn or so In some cases the lamp may now light but this is not an acceptable solution to the problem The connection between the lamp and socket is not under full spring pressure and electrical arcing will occur drastically reducing lamp life or resulting in socket burnout Vibration Sensitivity HPS lamps nearing the end of their service lives are very vibration sensitive Vibration causes a rise in lamp current above the end of life voltage HPS light color gives a good indication of relative lamp age Older HPS lamps give off a whiter light The color rendition they produce actually is better than new HPS lamps Vibration in the lamp due to wind or traffic can cause the lamp to cycle Vibration induced cycling is common in fixtures mounted on bridges You can simulate this vibration in a burning lamp by striking the mounting pole with a short length of lumber or by actually bumping the light fixture or light bulb with your hand If the lamp turns OFF when the pole is struck it is probably vibration sensitive The bump test also is a good way to
74. ther items or tools inside the bucket so there is no danger of them falling to the ground Always be certain the luminaire is properly grounded Use the grounding screw provided and run back to mechanical ground If the luminaire is not properly grounded it may become electrically hot if a component or wire inside the housing grounds itself to the housing This can happen if wires become frayed or ballasts or other components are damaged The danger of electrical shock then exists when the service technician touches the housing and grounds another part of his or her body The feeling of static electricity when you are near to or brush lightly against a luminaire is a sign that it may be electrically hot De energize the fixture immediately and inspect for a possible short to ground inside the housing If a lamp light bulb should break during installation or removal de energize the fixture and remove the broken lamp from the socket using a broken lamp base extractor Work carefully and use good judgment in all situations Most accidents are the result of carelessness INTRODUCTION TO HID LIGHTING HPS lighting systems are one of a group of systems classified as High Intensity Discharge lighting The HID lamp group also includes all mercury vapor and metal halide lighting systems The HID lamp group is one of the three major lamp groups used in modern lighting the others are incandescent and fluorescent To better unde
75. tion performed by a ballast is to limit the flow 14 of current through the lamp When the lamp starts and begins operation it basically is operating asa short circuit across the electrodes The ballast connected with the lamp acts to limit the current flowing to the lamp to keep it from destroying itself as resistance develops Without the limiting capability of the ballast the lamp would draw more and more current and eventually explode Providing the correct voltage to stabilize lamp operation We also have discussed how a ballast can act as a transformer to step up line voltage levels needed to start the lamp Many mercury vapor and metal halide lamps are designed to start using approximately 240 volts If this voltage is not available transformers are used inside the ballast to change the available voltage into the 240 volts needed for start up For example if 120 volts is applied to a 100 turn primary coil a secondary output coil with 200 turns will produce the needed 240 volts for start up American Electric Lighting AnSAcuityBrands Company By altering the ratio between the number of primary and secondary coil turns and including the necessary switching circuitry the ballast also can produce the 2500 to 4000 volt low energy voltage spike needed to start HPS lamps Regulating the flow of current through the arc discharge As mentioned in our discussion of lamp operation HID lamps reach a point of equilibrium
76. ure liaison and technical services section B Starting Pulse Requirements Measured across the socket terminals using a high frequency scope and high impedance probe 1 Pulse Peak voltage Min 2500 volts Max 4000 volts 2 The 4kv maximum is set to prevent internal arc over the starting circuit shall limit the pulse to a maximum of 4kv If the starting circuit is turned on at the high point on the power distribution voltage wave an abnormal transient can occur The starting circuit must limit high transients 3 Pulse width measured at 2250 volts Min 1 microsecond Max 15 microseconds 4 Pulse repetition rate Min 1 per cycle 5 Pulse peak current Min 0 2 amperes 6 Pulse position For near sine wave O C V within 20 electrical degrees of the center of the half cycle for reliable starting 7 The pulse must be applied to the center terminal of the lamp base 8 Starting pulses are not required after the arc has been established To avoid radio frequency interference and sub standard lamp performance it is recommended that the pulsing circuit be de energized during operation 9 Lamp starting is not affected by ambient temperature Ballast Marking The ballast should be clearly labeled to indicate the range of line voltage for which it is designed as published lamp performance ratings do not apply when the line voltage is outside these limits Short Circuit and Open Circuit Current To protect the balla
77. ures that may be encountered in the field Outages An outage is the most common type of failure The most common failed component is the lamp itself Replace the lamp in the outage fixture with a known good HPS lamp If the lamp does not come ON remove it and install the luminous wattmeter Troubleshoot using the luminous wattmeter as described in the previous section to pinpoint starter wiring or other power supply related problems It should be noted that wiring problems are not as common as starter problems Also check for a missing or defective capacitor bleed resistor Figure 20 If line voltage to the lamp is good and if there appears to be no wiring or photocontrol related problems replace the fixture Bleed Resistor FIGURE 20 A missing or defective capacitor resistor can cause a no start problem Cycling Cycling is the normal end of life failure mode for HPS lamps To summarize cycling can be caused by a normal end of life HPS voltage rise an intermittent electrical connection triggered by wind conditions or vibration from traffic a manufacturing defect in the lamp an overly sensitive photocontrol heat damage to photocontrol receptacle contacts or high ambient light level tricking the control A defective ballast or capacitor also can cause cycling Quite often when the service technician arrives at the location of a cycler the lamp will be operating properly This is because the conditions that may have been caus

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