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Osram HQI-E 150 W/NDL CL

1. 1 0 1 2 1 4 1 6 1 2 0 2 2 2 4 2 6 S m A V A V A 4 400 4 400 4 3 300 3 300 3 2 200 2 200 2 1 100 1 100 1 0 0 0 0 0 wl 1 100 1 100 y Y 1 200 2 200 2 200 2 300 3 300 3 300 3 400 4 400 4 400 4 S S S Fig 32 Asymmetrical conductivity with lamp current and lamp voltage during a normal lamp start This is only a transient effect which causes no harm Rectifying effect causes a high DC current component As a result the choke goes into saturated state with a marked decrease in choke impedance In extreme cases the lamp current is only limited by the choke s ohmic resistance Permanently excessive current causes a dramatic in crease in the temperature of the choke windings until the insulation is destroyed and short circuits occur between the choke windings These phenomena can occur with metal halide lamps see warning in IEC 61167 so that the standards have stipulated safety measures for luminaires see IEC 60598 1 Paragraph 12 5 1 Similar regulations exist for high intensity sodium vapor lamps in the IEC 60662 standard A safety measure in the circuit such as a thermal switch or a thermal fuse integrated into the magnetic ballast protects the circuit from such damage In accordance with a declaration issued by lamp manu facturers in reaction to standard EN 62035 published by the LIF Lighting Industry Fede
2. Long term reductions in lamp wattage cause the lumi nous flux to decrease with a shorter service life and a deviation in colour from the nominal values as also explained in chapter 5 Wattage reduction in high intensity discharge lamps If the supply voltage is too high the arc tube is op erated at too hot a temperature causing increased blackening and a shorter service life oO 3 gt E fe c lt p Ya Oo D Pe c oO oO hen A 95 100 Percentage of the nominal supply voltage UL in L in P in F if UL Lamp voltage IL Lamp current PL Lamp power FL Luminous flux Fig 11 Lamp parameters of a typical OSRAM HQI lamp over supply voltage N oO oO Ko oO oO 2 5 gt T S O 100 _ 6 J O hu A 95 100 Percentage of the nominal supply voltage UL in L in m PL in ni F in UL Lamp voltage IL Lamp current PL Lamp power FL Luminous flux Fig 12 Lamp parameters of a typical OSRAM HCI lamp over supply voltage 3 1 4 Capacitor for power factor correction The capacitor for power factor correction is necessary to correct the power factor of the system when operat
3. 11 01 2 OR ENDEN EEE EEE E E E E EUR NER RNLREREEERSERELEREIUEERECERREESERCEUHERERELERHERNEFEER 49 SA CIR OS een Biene ee en ee ae ee ehe ern 50 8 4 2 Protective measures to reduce Tagged eure 50 9 Disposal OF discharge Natt ra nenne 51 91 Statutory regurementS Sees ee ee ee aE EAEN AT RANKAR FERREE ARa KIAT p FRATON Na 51 9 2 Collection transport and disposal of discharge lamps at end of life u u2u202020s0nenenennenennnnnnne nenn 51 9 3 Ordinance on Hazardous Substances ans ae ee 51 To MIST Ot Erv aO ea ERTS NE E E E SE EES 52 Tr EIEE eA ne E TA E E ee ee 53 1 Introduction Metal halide lamps offer a number of advantages that generated in a small space the discharge lamps favor their use in ever broader areas of application almost correspond to a spot light source with These include high luminous efficacy a long service advantages in terms of light control and brilliance life and good colour rendering Because the light is of the illumination Table 1 The properties of metal halide lamps and resulting application areas Requirements in the application The height requires a lot of light Changing lamps is difficult and expensive Long operating hours Realistic reproduction of high value surfaces pictures products and TV images High illuminance values Luminaires should be small or discreet High mounting heights and wide spacing demand precise light control Property of metal halide lamps B
4. Ch 1 Lamp voltage Ch 3 Light signal zero line at the bottom Ch 2 Lamp current Ch 4 Lamp power Fig 18 Time curve for light signal and the electric parameters of a metal halide lamp In fast moving or rotating objects the stroboscope effect can cause an optical illusion that the object is moving more slowly or in the opposite direction or even at a standstill Stroboscope effects can be reduced or ruled out by operating luminaire groups on three different phases or by using electronic ballasts 4 Igniting and starting discharge lamps Some discharge lamps do not require an external ignition unit as the supply voltage is sufficient to ignite the lamp or because the lamp has an integrated ignition unit These lamps must not be used in installa tions with an external ignition unit or they will fail pre maturely due to internal arcing All other discharge lamps must be ignited by an addi tional unit Ignition units or circuits of varying types are used for this purpose At room temperature the filling particles are still pres ent in solid form metal halides or amalgam or in liquid form mercury The arc tube contains the start gas usually an inert gas such as argon or xenon between the electrodes The insulating gas filling in the arc tube must be made conductive in order to generate hot plasma This is carried out by high voltage pulses generated by a separate ignition unit or by the igni tion unit in an electronic
5. Every protective measure must refer to a reduction in effective radiant exposure Hdm Effective radiant exposure Hdm is the product of the radiation time tdm and effective irradiance Edm Reduction can consist of e avoiding the critical wavelengths by using corresponding filters according to the spectral sensitivity of the irradiated object e reducing the irradiance e reducing the exposure time e enlarging the distance to the luminaire Remarks on filtering the critical wavelengths Relative spectral sensitivity for most samples is not only very high in the ultraviolet range of irradiation and also still fairly high in the visible range for many exhibits This would mean that the short wave visible range also has to be filtered To what extent this is fea sible depends on the colour rendering characteristics and the changed colour temperature of the remaining visible radiation 9 Disposal of discharge lamps High pressure discharge lamps contain small quanti ties of mercury as an environment relevant substance Metal halide lamps can also contain thallium iodide as an additive This is why discharge lamps must be dis posed of separately from domestic waste and indus trial waste similar to domestic waste The last owner is obliged to dispose of the discharge lamp using the correct procedure Breakage of high pressure discharge lamps emits traces of toxic mercury and thallium halides More information on handling discharge
6. 0 7 and 0 95 depending on the operating mode The yellow Curve was generated by using a higher lamp power factor A to be more exact 1 05 1 n 3 Typical voltage and current waveforms as shown in Fig 6 show that while the current is approximately sinusoidal voltage is not After the current zero cross ing the voltage initially increases so called re ignition peak to then fall to a relatively constant value saddle see also chapter 6 2 2 and Fig 30 Voltage remains approximately the same beyond the maximum of the current and has the same zero crossing as the current So there are areas with high voltage which count towards the effective value of the voltage but don t contribute to the wattage as the current at that point in time is nearly zero This results in lamp power factors deviating from the value 1 If the lamp voltage is equal to zero the voltage drop across the choke is the entire supply voltage and the choke short circuit current is reached This is the max imum current that can flow through the choke inas much the current has no DC component see chapter 6 2 9 for effects of direct current components The following curves are typical for 150 W and apply in the same way to other wattages 5 higher lamp power factor Lamp power P in W Lamp current I in A Fig 5 Lamp current I lamp wattage P over the ratio of lamp voltage to supply voltage
7. 6 Fc and IEC 60068 2 29 Eb 7 6 2 Directives CE stands for Communaut Europ enne European Community and indicates compliance of a product with the corresponding European Directives The CE mark addresses authorities and is applied by the manufacturer CE marking was created primarily to warrant safe products for the end consumer in the free movement of goods within the European Economic Area EEA and its European Community EC The CE mark is frequently called a passport for the European Single Market The key directives for lighting products with corresponding compliance confirmed by applica tion of the CE mark are the electromagnetic compat ibility directive EMC 89 336 EEC and the electrical equipment directive 73 23 EEC also called the low voltage directive The low voltage directive demands that the product does not cause any harm to persons animals and things Compliance with the low voltage directive can also be verified by compliance with the safety standards OSRAM lighting products marked with CE fulfill the safety and EMC standards where applicable for the specific product see table 3 7 6 3 Certificates On the initiative of European manufacturer s associa tions European test and certification bodies have agreed to provide a uniform European evaluation of electrical products in order to indicate to the buyer of a product that it is safe and complies with state of the art
8. Burning position 45 angle Condensate Horizontal burning position Figure 38 Example for condensate precipitation in the lamp The balance between condensed and evaporated part of metal halides depends on the temperature of the arc tube wall The coldest spot of the tube where the metal halides have condensed is usually at the bottom of the tube 7 9 2 Projection of the condensate The light radiated from the plasma projects the con densate of the lamp so that the reflector needs to mix the emitted light to ensure homogenous radiation In particular when the burner is horizontal the radiation components from the upper half of the burner and the lower half of the burner have to overlap and be mixed during projection If the reflector cannot ensure this the condensate of the lamp is projected and appears on a white wall as a yellow mark Figure 39 Projection of the condensate by the reflector 7 9 3 Back reflection on the lamp The luminaire design needs to ensure that no radia tion is reflected back onto the lamp as this can cause thermal loads on sensitive parts of the lamp which normally leads to unusually early failures For a lamp with a quartz arc tube this may lead to the expansion of the tube or to a leak in the pinch area In lamps with ceramic arc tubes the so called sealing area at the ends of the capillaries is particularly sensi tive here overheating can lead to increased chemical reactions and
9. Condensation Alumina of Metall Halides in MH melt E Br Evaporation Corrosion of Metal Halides Evaporation f Metal Hali Transport of Orme armours soluble alumina in MH melt Conden sation of Deposition of alumina Metal Halides by saturation of HM melt due to cooling Fig 3 Comparison of ceramic corrosion between the different tube forms The advantages of POWERBALL technology compared to cylindrical solutions Better maintained luminous flux throughout the service life Improved color rendering particularly in the red Improved color stability during the service life More uniform operation independent of burning position More constant luminous intensity distribution Faster start up behavior 3 Ballasts for discharge lamps Since the discharge reacts to increasing lamp current with falling voltage which would cause the current to rise indefinitely until the fuse blows or another part of the circuit fails the lamp current must be limited by a ballast during operation This usually consists of an inductive circuit choke although in rare cases up to 400 W capacitive circuits are also possible although this usually results in a shorter service life In the blended lamp HWL the resistance of the filament serves as a series resistor for the high pressure mer cury discharge lamp In most cases additionally to the current limiting element an ignition device is needed to start
10. Information and can also be calculated using the following equa tion 1 X PFE 2yr sisx U JU xi P3 Py lt tange Eq 4 3 Cprc in F Capacitance of the capacitor for power factor correction U inV Rated supply voltage f inHz Supply frequency inA Lamp rated current Py in W Total active power lamp rated wattage plus choke loss wattage Ox Tolerable or desirable phase difference be tween the fundamental waves of the supply voltage and the supply current But this only corrects the power factor for the funda mental wave Phase difference remains for distortion i e the harmonic waves between current and voltage For this reason the overall power factor can also only reach values between 0 95 and 0 98 in practice A higher level of harmonic waves can cause resonance effects and destroy the lamp A power factor close to 1 is to be avoided as this can cause resonance between the choke and correction capacitor While a discharge lamp is starting up the power factor undergoes significant changes in value After ignition the lamp voltage is still very low with current higher than in steady state This is why the power factor in this state is still low inductive While lamp voltage increases and the lamp current falls the power factor increases to its nominal value of 0 85 0 9 As discharge lamps age it is normal for lamp voltage to increase causing the lamp current to fall according to the ballast
11. Parallel ignition unit Pulser ignition unit choke Luminaire Usrv Capacitor for PFC Fig 19 Simplified circuit diagram for conventional operation of high intensity discharge lamps with pulse ignition unit With a pulse ignition unit the choke must be insulated for its surges The pulse ignition units can normally take a load of 1000 pF permitting lead lengths of about 15 m between lamp and choke During ignition the lead carries high voltage from the choke to the lamp so that care must be taken to ensure that the supply lead socket and luminaire are adequately in sulated for the corresponding high ignition voltage This type of ignition unit is used in single phase grids 4 1 2 Semi parallel ignition unit Semi parallel ignition unit Luminaire Capacitor for PFC Fig 20 Simplified circuit diagram for conventional operation of high intensity discharge lamps with a semi parallel ignition unit Inthe semi parallel ignition unit part of the choke windings is used to transform the ignition pulses This means the choke must be adequately insulated for the high voltage and have a tap for the ignition unit As with pulse ignition units the ignition unit can gener ally take 1000 pF or approx 15 m lead length and the connection lead between choke and lamp must be insulated for the corresponding voltage levels A capacitor with minimum capacitance depending on the unit must be provided for compliance with th
12. The mean service life stated in the documents B50 val ue is the burning time within which maximum half of the lamps can have failed i e the survival rate at this point in time is at least 50 This is a value normally indicated by all lamp manufacturers Apart from the B50 value it is also common practice to indicate the times e g at which 10 or 3 of the lamps failed B10 or B3 Mean service life B50 max half the lamps have failed Economic life on account of the decrease in luminous flux and the increasing failure rate the illumination level of the installation has fallen below a required value The economic life is obtained by including the de crease in luminous flux over the service life in the calculation Multiplying the survival rate by the main tenance of the luminous flux provides the decline in luminous flux of the installation These factors are considered when preparing a maintenance schedule according to EN12464 see also 7 5 Maintenance of lighting systems with metal halide lamps Data on lamp survival behavior and luminous flux be havior can be found in the corresponding Technical Information One main reason for the reduction in luminous flux is blackening of the arc tube by electrode material which has settled on the tube wall throughout the service life Frequent switching overload operation use in con fined luminaires or high ambient temperatures can add to this blackening process and thus c
13. bulb during operation The measurement must be made under worst case conditions i e for the pinch temperature base up burning position for the outer bulb temperature horizontal burning position if permitted Compliance with the outer bulb temperature is not always sufficient to design a good luminaire I temperature read when switching off includes additional heating up of the thermocouple by radiation T 2 extrapolated temperature of the quartz glass when switching off A amp N oO measured temperature in C oO O 150 200 cooling time in s Fig 36 Cooling curve for HCI T 150 W 830 PB in closed luminaire lamp wattage 180 W T 4 temperature read when switching off includes additional heating up of the thermocouple by radiation Tag extrapolated temperature of the quartz glass when switching off Fig 37 Enlarged detail of figure 36 7 1 3 Measuring points for thermocouples in different lamp types The specific limit values are stated in the Technical Information The measured values are to be ascertained under the worst case conditions Both supply voltage and choke impedance influence lamp wattage A lower choke impedance and higher supply voltage each cause an increase in lamp watt age As the limit temperatures also increase with in creasing lamp wattage the worst case is to be ascer tained at the
14. characteristic curve P over U U In the lamp voltage range of OSRAM lamps approx 100 V the change in lamp wattage with changing lamp volt age is steeper In addition the maximum wattage that can be achieved with increasing lamp voltage is larger as shown in Fig 9 Normally the lamp voltage in creases with increasing service life see also chapter 6 Lamp service life aging and failure behavior According to equation Eq 4 1 wattage of about 150 W is achieved for a 150 W choke with a lamp voltage of 100 V The maximum the lamp wattage can increase to for a lamp voltage of 150 V is 175 W The higher achievable wattage can reduce the service life and possibly cause an increase of undesirable effects at the end of the service life e g lamp explosion OSRAM lamps are generally designed to operate at 230 V supply voltage and undergo corresponding ser vice life testing There are however also systems at 400 V e g for some discharge lamps gt 1000 W For these lamps the following explanations apply in the same way The use of high intensity discharge lamps is theoretically also possible at 277 V operating voltage with adapted impedance and ignition devices although such operation is associated with considerable disad vantages a An increase in negative effects must be expected at the end of the service life because wattage rises clearly above the nominal wattage when lamp voltage increases on account of the shift
15. discharge see chapter 4 Ignition and starting discharge lamps In modern luminaires an electronic ballast fulfils the function of igniting the lamp limiting the lamp current and controlling the lamp wattage 3 1 Inductive ballasts chokes The voltage across the electromagnetic ballast in creases as the current increases therefore a stable working point can be achieved in the series connec tion of the discharge lamp and the choke Core PFC capacitor La lamp U supply voltage Ch choke Fig 4 Discharge lamp with inductive ballast ignition unit has been left out the various possibilities are fea tured in chapter 4 Ignition and start up of discharge lamps Describing the relationships of current and voltage requires a system of differential equations which can not generally be solved The following approximation formulas describe how the lamp current and lamp wattage depend on the relationship of lamp voltage to supply voltage 3 P U oy 1 2 0 25n Gi 4 1 Ir 1 n 0 25n GI 4 2 whereby 1 n 3 approximation for the lamp power factor A en lamp wattage in W eer supply voltage in V Man ratio of lamp voltage U to supply voltage U Z an choke impedance Charting the equations results in the curves shown in Fig 5 The difference between lamp wattage and the product of lamp voltage and lamp current is called lamp power factor It reaches values between
16. field strengths result ing in a larger number of charge carriers at the same voltage than in pure gas Examples for the Penning effect include mercury in argon for metal halide lamps and argon in neon for some discharge lamps 4 5 Ignition at low ambient temperatures Most metal halide lamps with wattages lt 400 W can be operated at ambient temperatures of 50 C The usually evacuated outer bulb and the luminaire ensure that the arc tube is thermally decoupled from the surroundings so that the normal operating parameters are achieved as far as possible For HQI 2000 W NI and 2000 W DI ignition is only permitted to 20 C In the ignition units the ferrite core is sensitive to tem perature that is the rated ignition voltage is lower at lower temperatures Some ignition unit manufacturers recommend the use of ignition units without cut out as the ferrite core in this case is heated up by the loss es during failed ignition attempts so that the specified ignition pulse levels are reached again There are also ignition units with an additional integrated resistor for heating the ignition unit so that these are approved for temperatures down to 50 C Here again it takes a while after switching the ignition unit on until it has heated up enough to reach the specified ignition pulse levels For specific applications such as in cold storage hous es semi parallel ignition units can be used which per mit longer lead lengt
17. in A i D 3 8 80 a 30 A O N oO oO a Fig 10 Lamp current I lamp wattage P over the ratio of lamp voltage to supply voltage U U at U 200 V There is a major drawback that with lower supply volt age there is also less voltage available for re ignition after the current has passed zero crossing If the mo mentary supply voltage is lower than the re ignition voltage the lamp goes off Normally the lamp voltage and also the re ignition peak increase with increasing service life see also chapter 6 Lamp service life ag ing and failure behavior That means that a reduction in supply voltage causes a shorter service life in many lamps 3 1 3 Influence of deviations in supply voltage When operating metal halide lamps on a choke the lamp parameters change depending on the supply voltage To limit the associated variation in lamp pho tometrics a maximum deviation in supply voltage of 5 from the nominal values for the supply voltage is permitted in the short term or maximum 3 in the long term For deviations over a longer period of time suitable ballast tap must be selected As choke imped ance also influences the lamp parameters via the cor respondingly adjusted lamp current this is allowed to deviate from the nominal values by maximum 2 Remote mounting can also cause noticeable de creases in voltage see also chapter 7 4 Leads to luminaires
18. isolate the connection contacts in the installation procedure if this is not safeguarded by the socket alone e Lamp pins Only use lamps with clean metallic contacts Oxidized contacts result in high transition resis tances and generate high operating temperatures The surface of the lamp pins must be smooth and must not show any visible traces of mechanical machining in the area of contact with the socket contact as otherwise the socket contacts can be damaged 7 4 Leads to luminaires The lead cables to the luminaires must be rated for their conditions of use taking account of adequate heat and UV resistance mechanical strength electric strength and current carrying capacity as well as giv ing due consideration to the effect of cable lengths e g when remote mounting is required Cable resis tance grows linear to cable length The resulting volt age drop across the cable reduces the effective supply voltage The effects are described in chapter 3 1 3 Influence of deviations in supply voltage Various factors must be considered when choosing leads in the lamp circuit e The voltage drop across the lead depends on the flowing current and can be reduced by using cable with a larger cross section e It should also be borne in mind that cable resis tance increases with higher ambient temperature The resistance of a copper cable rises by about 10 for an increase in temperature of 25 C e Consideration mu
19. lamps is available at http www osram com weee In any case the legal regulations of the respective country have to be respected 9 1 Statutory requirements Directive 2002 96 EC WEEE waste of electrical and electronic equipment came into effect on 13 February 2003 It applies in all Member States of the European Union Similar systems are also in use in some non European countries The main aim of this EU directive is the re use materi al recycling and other forms of recycling of such waste products in order to reduce the quantity of waste and to protect resources particularly by means of reuse and recycling All manufacturers and importers of electrical and electronic equipment are obliged to take back their products and to ensure that they are treated reused or recycled OSRAM lamps intended for recycling are marked with this symbol General information on disposal can be found at http www osram com weee 9 2 Collection transport and disposal of discharge lamps at end of life During transport to disposal or collection points please make sure that the lamps are adequately protected from breakage which would result in the emission of mercury Transport of the used discharge lamps by the last owner is not subject to transport permission The lamps do not constitute dangerous cargo in accor dance with the corresponding regulations GGVS GGVE and ADR and RID 9 3 Ordinance on Hazardous Substances Discharg
20. of the luminaire The glare can also be reduced by using protected lamps such as HCI TX P because the fact that there is no front glass at the luminaire means that there is no reflex glare on the front glass To achieve a homogenous colour radiation facetted and matt reflectors should be used Diffuser tubes around the lamp are not suitable In lamps with a reflector casing the reflector should be smoothly cut at the opening and should not have a neck It is more difficult in cases where the reflector itself comprises the outer part of the luminaire If a reflector neck is used here e g to prevent the emission of light scatter this leads e g in ceramic lamps to a higher temperature load in the socket based capillaries The extent of the damage depends on the following parameters e Extent of the spatial covering of the reflector neck and the capillaries less is better e The diameter of the reflector neck bigger is better e Level of reflection of the reflector neck matt is better than mirrored e Overall volume of the reflector bigger is better The service lives stated by OSRAM only apply to lamps operated in luminaires that do not reflect back on the lamp They are based on a switching rhythm 11h ON 1h OFF 43 44 If back reflecting construction elements are used in the luminaire design the guarantee for the lamps can be restricted or even completely suspended It is therefore recommended contacting OS
21. op erating temperature The times required to achieve the lit up status are therefore clearly shorter than in the cylindrical version as shown in Fig 23 180007 T HCI T POWERBALL 150 W 16000 cylindrical HCI T 150 W 14000 I T 150 W in Im 12000 10000 os Q oO oO x S 7 5 fe E 5 i 100 Time ins Fig 23 Start up behavior of luminous flux in various metal halide lamps operating with an OSRAM elec tronic ballast The time it takes to reach a steady state depends on the start up current and the associated wattage input If the current is too high the electrodes will be dam aged causing the walls to blacken The standard for metal halide lamps IEC 61667 therefore limits the start up current to twice the nominal lamp current With OSRAM POWERTRONIC the start up is faster than with a conventional ballast as shown in the fol lowing Fig 24 HQI T 150 W at OSRAM PTU HQI T 150 W at CCG Luminous flux in Im 100 Time ins Fig 24 Start up behavior of luminous flux of a HQI T at various ballasts 5 Reducing the wattage of high intensity discharge lamps 5 1 Introduction High intensity discharge lamps generate light by excit ing mercury and other metals within an arc tube into a plasma generated by the current flow between two electrodes Discharge lamps must be operated with a ballast and are rated for a ce
22. over service life The system wattage with conventional ballasts fluctuates significantly over the service life of the lamp This results from the change in lamp volt age which can increase by up to 30 throughout the service life see also chapter 3 1 2 resulting in considerable fluctuations in lamp wattage By contrast electronic ballasts operate the lamps always with constant wattage throughout the entire service life The maximal tolerated fluctuation is 3 This means for example that for a 70 W ceramic arc tube lamp the electronic ballast constantly provides the lamp with the rated 73 W 3 2 3 2 Lamp service life and cut out at the end of the service life A detailed description of the lamp service life and fail ure behavior using conventional ballasts can be found in chapter 6 Electronic ballast operation also offers considerable advantages in terms of lamp service life and cut out behavior at the end of the service life Comprehensive laboratory tests and extensive practi cal experience show that operation on electronic bal lasts has a significantly positive influence on the lamp service life Precise but gentle lamp ignition a more stable thermal balance thanks to constant wattage supply and above all a clearly reduced tendency to go out by avoiding re ignition peaks all lengthen the lamp economic life for ceramic arc tube lamps by up to 30 on average The electronic ballast also shows its strengths at the e
23. power is not permitted as this can cause consider able colour deviations much poorer luminous flux maintenance and shorter service lives Basically it is possible to dim POWERBALL HCI While the higher thermal load capacity of the round ceramic arc tube permits an improved dimming behav iour in terms of luminous efficacy and colour rendering compared to metal halide lamps with quartz arc tube or with the normal cylindrical ceramic tube dimming still causes a shift in the chromaticity coordinate Dimmed lamps show a greater drop in light output and wider colour spread throughout the service life It is important to avoid these effects for interior light ing They are more apparent when operated on con ventional control gear than on electronic control gear OSRAM therefore recommends not to reduce power with currently available lamps on conventional control gear or for indoor lighting The type of dimming has a great impact on the results It is recommended to use only adjustable Electronic ballasts with squarewave operation and to completely avoid dimming via reducing the supply voltage or leading edge or trailing edge phase dimmers It is not possible to guarantee that dimmed lamps will be able to meet the product properties In any case the lamp should run for at least 15 minutes with 100 wattage after being switching on so that the lamp can light up correctly A warranty regarding lifetime can only be given when approved
24. technology This resulted in the ENEC agreement and the ENEC mark ENEC European Norms Electrical Certification Prerequisite for be ing granted an ENEC certificate is compliance of the product with the corresponding European safety and performance standards The production procedure must have a quality management system e g based on DIN EN ISO 9002 The corresponding certification body carries out regular audits to monitor whether the system requirements are being met The number next to the ENEC symbol identifies the certification body All current certification bodies that have signed the ENEC agreement can be found together with the corresponding countries and the register of issued ENEC approvals on the ENEC internet website www enec com 41 42 If an ENEC mark is issued for a product by a certifica tion body then the European certifying bodies partici pating in the ENEC agreement treat this product as if they had tested and certified it themselves Further testing and certification by one of these bodies is no longer necessary The ENEC mark can be obtained for luminaires for which a European standard exists Luminaire accesso ries such as ballasts ignition units lamp sockets and Capacitors can also be issued an ENEC mark if they satisfy the corresponding EN standard 7 7 Radio interference Selected luminaires must comply with the international requirements such as CISPR 15 and CISPR 22 A or B and in practice r
25. that can be perceived by the human eye Flicker is evaluated according to EN 50006 standard for example with a flicker factor F10 as Fo E mE whereby m f time dependent modulation depth of the luminous intensity filter curve for flicker sensitivity depending on flicker frequency G According to Afshar 2 adapting the evaluation also to short term changes and implementation in a filter for a light signal such as in Fig 15 results in values for the flicker factor as shown in Fig 16 The perceptibility threshold is assumed to be 1 The values in this ex ample remain below 1 i e no visible changes can be perceived in the light 20 12 24 2016 Fig 15 Luminous intensity of a metal halide lamp at 50 Hz choke operation shown in arbitrary units A A f n j N Y LA My Fig 16 Flicker factor calculated from the luminous intensity signal for a metal halide lamp at 50 Hz choke operation shown in arbitrary units Temporal modulation sensitivity curve normalized oy 0 Ls T mi id bJ f 10 20 30 40 50 60 70 80 Frequency H7 Fig 17 Eye sensitivity curve for flicker as per Kelly 1960 and Henger 1985 17 18 There is a delay of just a millisecond between the current maximum and the luminous flux maximum as shown in the following drawing MPower Power DC RMS 150 52 VA Window 1 M PD tty Et yy A TET TEL TTT
26. the hot arc tube thermally from the surroundings similar to the principle of a thermos flask But there are also some discharge lamps without outer bulbs as well as lamps with gas filled outer bulbs In contrast to low pressure discharge there is high pressure and a high temperature in a discharge tube In an arc tube gas discharge works through excitation of the luminous additives metal halide salts and the mercury is excited by the current flow Visible radia tion characteristic for the respective elements is emit ted The mixture of the visible radiation of the different elements results in the designed colour temperature Outer bulb Electrodes ir N KA N A Arc tube Fig 1 An example of how a metal halide lamp works based on a double ended lamp with a quartz arc tube and colour rendering for a particular lamp In the op erating state the mercury evaporates completely The other elements involved are present in saturated form at the given temperatures i e they only evaporate in part the rest is in liquid form at the coolest point in the arc tube The fraction of the filling that has evapo rated depends on the temperature of the coolest point on the arc tube wall and also varies for the different filling components Changes to the temperature of the arc tube wall can change the composition of the metal halides in the discharge thus also changing the colour properties of the lamp Hg Mercury Me Metal
27. the choke impedance must not deviate from the nominal values by more than 2 see also chapter 3 1 3 Influence of deviations in supply voltage e Maximum permitted supply voltage deviations 5 in the short term 3 in the long term use other tap on the choke if necessary e Maximum deviation of choke impedance 2 e The choke must be protected against overheating according to the standard thermal fuse As per the IEC 61167 standard ballast units for MH lamps must by protected from overheating through rectification This can be done e g with a thermal fuse tested according to IEC 598 1 Annex C 3 1 1 American circuits for ballasts In this context it is important to note that the supply voltage in America has a different frequency 60 Hz As the inductive resistance of the choke depends on the frequency in this case it is important to use a designated ballast for the corresponding frequency In addition both lamps and ballasts in the USA are stan dardized by ANSI the American National Standards Institute To operate the systems correctly lamps must be operated with corresponding ballasts Ratings des ignations are required by ANSI to be marked clearly on all products allowing users to clearly identify system agreement 3 1 1 1 Autoleak transformer or high reactance auto transformer If the supply voltage is smaller than around twice the lamp voltage as is the case for example in the USA or Japan the
28. the entire radiation output is emitted monochromati cally in the wavelength of maximum eye sensitivity 555 nm then the theoretical maximum luminous effi cacy is 683 Im W With uniform distribution of radiation over the range of 380 780 nm approx 196 Im W is possible Luminous flux Luminous flux is the light output of a light source Unit 1 lumen Im Fig 42 Definition of luminous flux V A Day vision Le 30 cd in ar SW Night vision 0ieme EL Fig 43 Spectral brightness sensitivity V x for photopic vision and V N for scotopic vision Light intensity Light intensity is the measure of lightoutput in a specified direction Unit 1 candela cd Fig 44 Definition of luminous intensity Illumination Average illumination of a surface is luminous flux per unit area Lux Lumen Fig 45 Definition of illuminance Luminance Luminance is the measure of the brightness that the eye has of a surface Unit 1 candela m cd m Luminance depends on the surface of the area seen by the eye and on the luminous intensity radiated from the surface towards the eye illuminated surface Fig 46 Definition of luminance Luminous Irradiated light in Lumen Im efficacy spent electrical power in watt GI 9 1 45 46 8 1 Night vision The luminous flux measured in lumens is the irradi ated output of a light source evaluated by the eye It is
29. thus increasing the re ignition peak causing the lamp to go off earlier For the phase control with trailing edge or other methods where supply voltage is temporarily switched off or reduced suitable means are required to provide an uninterrupted smooth lamp current to prevent the lamp from flickering and going off Increased blackening and therefore a drop in luminous flux must be expected in all versions compared to full load operation 5 2 3 Increasing choke impedance or decreasing lamp current Increasing choke impedance reduces the current through the lamp The supply voltage remains the same so that the voltage is still high enough to re ignite the lamp The flatter zero crossing of the current can however be expected to cause greater cooling down of plasma and electrodes with greater blacken ing as a result of the processes at the electrode during re ignition The blackening therefore causes a greater drop in luminous flux compared to full load operation Fig 28 Amplitude modulation e g by choke change over The least disadvantages are to be expected by reduc ing current in rectangular mode The steep zero cross ings mean that lower re ignition peaks and less black ening from sputtering can be expected If a switchover to other chokes is used for dimming lamps with a wattage gt 400 W they must be left to burn at 100 for at least 1 hour 5 2 4 Change in frequency for high frequency mode A change in
30. to photopic light When the illumination level decreases the rods are therefore more active while the cones become inactive The effective seen lumen will differ from the mea sured photopic luminous flux When the illumination level falls the effective luminous flux e g of yellow high pressure sodium lamps decreases while the effective luminous flux of white light with a higher share of green blue light increases Figure 47 shows the radiation output of a HCI TC 70 W NDL and a NAV T 400 W Super 4Y normalized in the interests of comparability to a luminous flux of 1000 Im The diagram shows the relative distribution of the radiation in the spectrum mm NAV T 400W SUPER 4Y mmm HCI TC 70W NDL m m eo O1 oO EEN u E c Te oO oO Weighting factor for eye sensitivity curve Fig 47 Physical radiation output in W per 1000 Im and per 5 nm In Fig 48 the physical radiation output has been mul tiplied by the V A curve to ascertain the luminous flux per 5 nm in each case Integration of the values for all wavelengths between 380 nm and 780 nm results in the specified 1000 Im for both light sources The NAV lamp radiates more light in the range around 580 nm which is near the maximum of the V A curve This contributes to a high luminous efficacy On the other hand there are some
31. 05 C for ignition units consider manufacturer s instructions A higher ambient temper ature means that luminaires are increasingly switched off triggered by the thermal protection It can therefore be assumed that the high ambient temperature has a distinctly negative influence on the service life of lamps and luminaires Luminaire design has a great influence on the tem perature of the parts Heat generating parts such as chokes and filter coils can be mounted on materials with good heat conducting properties and adequate ventilation openings to ensure there is ample heat dissipation The greatest possible spacing should be kept between heat sensitive parts such as ignition unit and capacitors and heat generating parts If neces sary forced cooling should be provided by ventilation elements At the end of the lamp service life far higher tempera tures than normal can occur in the pinch area caused by outer bulb discharges see also chapter 6 2 Failure mechanisms of metal halide lamps The socket in the immediate vicinity of this point must be rated for that temperature 7 3 Lamp holder Metal halide and high pressure sodium lamps have many different bases These include for example RX7s 762 GS 0 GX 10 GX8 5 GU6 5 G12 G22 GY22 E27 E40 and K12s depending on whether the lamps are single or double ended All sockets must be rated for the typical conditions for discharge lamps i e high ignition voltage and
32. 5 100 T 4 7 Start up behavior of metal halide lamps After igniting the lamp and heating the discharge the discharge runs initially only in the start gas The mer cury and the metal halides are still in liquid or solid form on the arc tube wall The voltage across the discharge is initially still very low The start gas argon radiates a little in the visible range weak violet light which is why the luminous flux in the initial phase is still very low Through power consumption in the lamp first the mer cury and then also the metal halides begin to evapo rate The individual filling particles evaporate at differ ent rates resulting in differing ratios of the particles during runup The dominance of individual particles in the start up phase results in the colour phenomena during this period shown in Fig 22 Only after a few minutes having reached the steady state is the re quired composition achieved producing the full lumi nous flux and the required light colour after 60s y 6500K CRI 36 after 120s y 4000K CRI 92 Fig 22 Course of light parameters of a HCI T 150 W NDL during start up 21 22 The new round ceramic arc tube POWERBALL has a uniform wall thickness without thick ceramic plugs as in the cylindrical ceramic type The mass is there fore only about half that of the cylindrical version This means less energy and therefore less time is needed to bring the POWERBALL ceramic arc tube up to
33. POWERBALL HCI units cf online catalogue on the POWERTRONIC PTo are dimmed Operation of POWERBALL HCI on the POWERTRONIC PTo The combination of POWERBALL HCI and POWERTRONIC PTo allows energy saving operation everywhere where optimised colour rendering is not important for example outdoor lighting The PTo with squarewave operation and optimised ig nition runs the POWERBALL HCI lamps ideally down to 60 of the lamp output rated value No significant negative effects arise even when the output is reduced to 85 of the rated output Even when operated at between 85 and 60 of the rated output this does not negatively effect the failure rate However increasingly the lamps have a slightly green touch and the colours may deviate from each other colour spread The luminous flux drops slightly more throughout the service life in dimming mode than when operated at 100 on the PTo This effect can be reduced if the lamps are operated via a combination of dimming and 100 operation Dimming causes a reduction in light output and colour change Squarewave operation is recommended for dimming For outdoor lighting optimised operation of the approved POWERBALL HCI on the POWERTRONIC PTo There is no warranty for dimmed POWERBALL HCI A warranty regarding lifetime can only be given when approved POWERBALL HCI units cf online catalogue are dimmed on the POWERTRONIC PTo 5 3 2 Dimming of ot
34. R13 Skin colour R14 Leaf green EI Apart from the first 8 colour rendering indexes DIN 6169 also defines other test colours which are four saturated colours and additional test colours The further test colours permit a more precise description of the colour rendering properties of the light source In principle it is possible to define any random number of many different test colours Table 5 Colour rendering levels Evaluation Colour rendering level Colour rendering index CRI Very good Good Suboptimal 4a O89 Thanks to a higher possible wall load the colour ren dering properties when using POWERBALL technology have been visibly improved compared to the lamp with cylindrical ceramic arc tube A further improvement CSRS D DO amp 120 HCI T POWERBALL specific Color rendering index 2 3 4 Typical lamp with HQI T POWERSTAR cylindrical ceramic Fig 52 Comparison of the specific colour rendering indices for various metal halide lamps 50 has become possible due to additional adaptation of the HCI Shoplight which achieves the best colour ren dering properties of all metal halide lamps Figure 49 shows the values of the colour rendering indices 1 to 14 for four different lamp types with the correlated co lour temperature of 3000 K The advantages can best be seen for colour rendering index R9 for saturated red but the superiority of POWERBALL
35. RAM if there is any doubt during the design stage In the case of lamps with back reflecting construction elements tests should always be carried out to as certain whether the extent of the lamp damage can at least be assessed as minimal It is useful to do comparative burning tests with non back reflecting luminaires If in this case of e g ce ramic lamps visible deposits in the outer bulb of the lamps occur at an early stage in the tested luminaires the burner has overheated due to back reflection Due to the fact that the failure rate of ceramic lamps depends on the switching frequency a lamp test of this kind can be accelerated by increasing the switch ing frequency to e g 3h ON 1h OFF 8 Light and colour Light is the part of the electromagnetic spectrum which can be seen with the eye By definition the per ceptible wavelength range is 380 780 nm although radiation can also be perceived as colour in the near infrared range Similar to visible light ultraviolet and infrared variation belong to the electromagnetic spec trum 100 380 9780 1900 Visible Wave length nm Fig 41 Visible light as part of the electromagnetic spectrum Different wavelengths can be perceived to different extents The maximum of the sensitivity curve for photopic vision is at 555 nm The light output lumi nous flux is ascertained by multiplying the physical radiation output with the eye sensitivity curve V A see Fig 43 If
36. U U Z 99 Q for a 150 W lamp Voltage in V 140 120 100 80 60 40 20 0 20 40 60 80 100 120 140 25 Time in ms Fig 6 Graph showing lamp voltage and current ofa 150 W lamp when operated at a choke applies in the same way to other wattages This lamp behavior results from the relatively flat zero crossing for sinusoidal current When the current ap proaches zero the plasma temperature decreases and the electrodes also cool down The recombination of electrons with ions reduces conductivity After the zero crossing the conductivity is too low to take up the current that the choke wants to drive As a result the voltage through the lamp increases again significantly until the lamp reignites The higher voltage results in a higher ionization rate that increases conductivity again so that voltage falls By contrast current and voltage for the rectangular waveforms of an electronic ballast change signifi cantly faster from positive to negative half wave or have a faster commutation times see chapter 3 2 Electrical ballasts ECG so that the plasma has little chance to cool down The instantaneous voltage required from the electronic ballast is therefore sig nificantly lower than for the choke This is one of the advantages of electronic ballast as one of the failure mechanisms of metal halide lamps is to extinguish
37. Ze wWwWw osram com nalide lamps Instructions for the use and application SEE THE WORLD IN A NEW LIGHT Gontents T HPO GING LO ee na an a ee one an ee een ee near A 2 Howa Stal Halle lamp WOM Seesen eier ee een EE nE RE aR 5 2 Quarz discharge UDE une een ie 6 2 2 Ceramic discharge tube PCA polycrystalline alumina us0244020000n0 neuen en nennen nn en nn anne nn nennen 6 22 1 1St eneralon cylindrical TO Messana ee serien ee see 6 2 2 2 2nd generation freely moldable ceramic POWERBALL 222240002020 2020 anno nn nn nn nennen nennen nn 6 gt Ballasts Tor CISC IARC lat Seen Bee nee ae en ae een ee 8 3 1 Inductive ballasts ONOKE re een ee ESAR SA aS 8 3 1 1 American circuits f r Dallas aaa aa aaia 9 3 1 2 Variation in supply voltage for adapted inductance us0s002020n0nnnnnnonnnnnnnnn nenne nenn nnnnnnnen 10 3 1 3 Influence of deviations in supply VYOlaQge nissan en een ee schein 11 3 1 4 Capacitor Tor power factor correction une ee 11 32 Elecironic control gear NE Eee reden onceceeneesatoueceetee REE eA IA eaea roni ERa 12 3 2 1 Structure and functioning of an electronic ballast usu20202000000 nnnnn nenn nenn nennen en en nennen 12 3 2 2 Service life and temperature una en en e 13 3 2 3 Advantages of operation with electronic ballast POWERTRONIC PTi 20202020202020 nenn nennen 13 3 3 Influence of harmonic waves and correspon
38. adio interference is low enough so that no negative effects are expected on the environ ment Even though ignition pulses from an ignition unit with out cut out can cause radio interference if with a de fective lamp there are no regulations for this case The interferences can be extensive One solution is swift replacement of the defective lamp or use of ignition units with a cut out feature These detect the defect or the absence of the lamp and switch off the ignition unit after a limited time period of futile ignition attempts The unit has to be disconnected from the grid power supply to reset the timer 7 8 ROHS conformity All products brought onto the market in Member States of the European Union by OSRAM since 1 July 2006 comply with the requirements of the EC directive 2002 95 EC on the restriction of the use of certain hazardous substances in electrical and electronic equipment ROHS As a fundamental rule our products contain no cadmi um hexavalent chromium polybrominated biphenyls PBB polybrominated diphenylether PBDE or lead and fulfill the requirements of the directive for the use of mercury 7 9 Optical design of reflectors 7 9 1 Condensate in the lamp While the mercury in metal halide lamps evaporates completely when operated at full power the metal ha lides are in saturated state There is therefore always a surplus of condensed metal halides at the cold spot in the arc tube
39. after the zero crossing of current and voltage For sinusoi dal lamp current the current decreases gradually be fore the zero crossing As the plasma is heated by the current flow a decrease in current causes the plasma to cool down and reduces its conductivity After the zero crossing the cooled plasma can initially no longer conduct the current through the lamp As the current does not rise through the lamp an increasing amount of supply voltage falls across the lamp The rise in voltage causes the ionization of the plasma and there fore the current to increase again meaning the plasma is reignited hence the name re ignition peak If the re ignition peak exceeds the level that can be provided by the supply voltage the lamp goes out 21 28 This is one of the advantages of the rectangular elec tronic ballast As the zero crossing for current is very steep the events of limited current availability are very short and the plasma has little chance to cool down Lamp voltage Supply voltage Lamp current Re ignition Fig 30 Re ignition peak supply voltage and lamp current The lamp voltage and the re ignition peak increase with progressing lamp age in addition this parameter also depends on the ambient temperature and increas es while the lamp is heating up This results in what is known as cycling where the lamp periodically goes off and on again The re ignition volt
40. age increases while the lamp is heating up and continues to increase until the luminaire is completely heated through This is why it can happen that the lamp does not go off until after several or even many minutes of burning time Fig 31 shows a lamp with high re ignition peak After the zero crossing the current barely starts to flow This is why the voltage loss across the choke is low and nearly the entire voltage supply falls across the lamp with lamp voltage following supply voltage The cur rent flow decreases even further from period to period so that conductivity continues to fall in the end the voltage required to re ignite the plasma is higher than the supply voltage the lamp stays off after the zero crossing Supply voltage Lamp voltage N Lamp current Fig 31 A lamp goes out because the re ignition peak is too high A decline in the supply voltage can also cause the lamp to go out It is only when the lamp has cooled down sufficiently that re ignition is possible with the normal ignition units After cycling for a long time it is possible that the lamp will not ignite at all This fault is not critical if the ignition unit does not suffer from the frequent ignition attempts 6 3 3 Broken lead or broken weld This can be caused by material fatigue or extreme mechanical load Normally this is a non critical fault in very rare cases a loose contact can cause hig
41. al halide lamps there can be individual differences in colour from lamp to lamp caused by external influences such as supply voltage control gear burning position and luminaire design Unless stated otherwise the specifications apply to TS types for horizontal burning position and to T and E types up to 250 W for base up burning position For lamps gt 400 W the horizontal burning position applies for the T lamp For lamps with 400 W the burning po sition depends on the type as stated in the catalogue Should deviating burning positions be used in prac tice this could cause changes in luminous flux colour temperature and service life The POWERBALL HCI with its round arc tube is less critical than conventional cylindrical ceramic tubes The luminous flux is generally independent of the ambi ent temperature itself outside the luminaire However too high ambient temperatures can cause increased arc tube blackening in the long run Also special igni tion units are required for lower ambient temperatures down to approx 50 C HQI 2000 W lamps with inte grated auxiliary discharge are only permitted to 20 C For measurement of the electrical photometrical and colour characteristics HQI TS and HCI TS lamps shall be operated within a luminaire simulator Details on luminaire simulator Quartz tubes around the lamp for determining the lamp data for HQI TS and HCI TS can be found in IEC 61167 Annex B 2
42. andard EN 12464 National Institute for Occupational Safety and Health polycrystalline Alumina Room Maintenance factor as per standard EN 12464 suprachiasmatic Nucleus Waste Electrical and Electronic Equipment Maintenance factor as per standard EN 12464 Zentralverband Elektrotechnik und Elektronikindustrie e V Central Federation of the Electrical and Electronic Industry 11 Literature 1 Kelly D H 1961 Visual Response to Time Dependent Stimuli I Amplitude Sensitivity Measurements JOURNAL OF THE OPTICAL SOCIETY OF AMERICA Vol 51 Nr 4 On Pages 422 429 Henger U 1986 Untersuchungen zur Entwicklung eines Messger tes zur Bestimmung des Flickerfaktors Licht 86 7 Lichttechnische Gemeinschaftstagung 2 Afshar F 2006 Light Flicker Factor as a Diagnostic Quantity for the Evaluation of Discharge Instabilities in HID Lamps LEUKOS Vol 3 No 1 July 2006 3 Sturm Betriebsger te und Schaltungen f r elektrische Lampen Siemens AG Verlag 99 www osram com OSRAM AG Head Office Hellabrunner Strasse 1 81543 Munich Germany Phone 49 0 89 6213 0 Fax 49 0 89 6213 20 20 www osram com 106T020GB 04 12 pd OSRAM HID Subject to change without notice Errors and omission excepted E fe i a DL responsible sources FSC C015982 member of a voltimum n com M FSC
43. aps and holders together with gauges for the control of interchangeability and safety Part 1 General requirements and tests 60061 2 Lamp caps and holders together with gauges for the control of interchangeability and safety Part 2 General requirements and tests 60061 3 Lamp caps and holders together with gauges for the control of interchangeability and safety Part 3 General requirements and tests 60061 4 Lamp caps and holders together with gauges for the control of interchangeability and safety Part 4 General requirements and tests Edison screw lamp holders Barrel thread for lamp holders with shade holder ring Miscellaneous lamp holders Safety u Performance 60155 Glow starters for fluorescent lamps a 60155 Glow starters for fluorescent lamps 61048 Auxiliaries for lamps Capacitors for Capacitors for use in tubular fluores use in tubular fluorescent and other cent and other discharge lamp discharge lamp circuits General and circuits Performance requirements safety requirements 61347 1 Lamp control gear Part 1 General and safety requirements 61347 2 1 Lamp control gear Part 2 1 Auxiliaries for lamps Starting Particular requirements for starting devices other than glow starters devices other than glow starters performance requirements Accessories 61347 2 4 Lamp control gear Part 2 4 Particular requirements for d c supplied electronic ballasts for general lighting DC supplied electronic ballast
44. ation The capacitors are differentiated as follows depending on the arrangement and form of use INDIVIDUAL OR FIXED COMPENSATION where the in ductive wattless power is corrected directly where it occurs relieving the strain on the leads typical for individual con sumers usually working in continuous mode with constant or relatively large wattage discharge lamps asynchro nous motors transformers welding equipment etc 11 12 The parallel capacitor has no influence on lamp behavior GROUP COMPENSATION where one joint fixed ca pacitor is allocated to simultaneously working induc tive consumers similar to individual correction motors located close together discharge lamps Here again the strain on the leads is relieved but only up to the point of distribution to the individual consumers Un der unfavorable conditions resonance can be caused in two phase grids CENTRAL COMPENSATION where a number of ca pacitors are connected to a main or sub distribution station This is the normal procedure in large electrical systems with changing load Here the capacitors are controlled by an electronic controller which constantly analyzes the demand for wattless power in the grid This controller switches the capacitors on or off to cor rect the current wattless power of the total load and thus reduce overall demand in the grid Capacitor for power factor correction values are stated for every lamp type in the Technical
45. ballast Constantly available free charge carriers electrons are accelerated by high voltage providing them with sufficient energy to ionize atoms on impact and generate more free charge carri ers This process similar to an avalanche finally pro duces conductive hot plasma within which the current flow excites the partly evaporated metal halide filling such that light is radiated The ignition voltage required to generate a breakdown between the electrodes depends on the spacing be tween the electrodes the filling pressure of the gas between the electrodes and the type of gas Examples for using these principles include the use of auxiliary electrodes or the use of Penning gases see chapter 14 4 Ignition at low ignition voltage Penning effect The sockets and cables must be suitably designed for the high ignition voltages In particular with the E27 sockets for single ended screw base discharge lamps care must be taken that a similar socket E27 for in candescent lamps is not used which does not meet the requirements When lamps are defective or no lamp is inserted continuous operation of the ignition unit can possibly damage the ignition unit or the luminaire It is therefore advisable to switch the ignition unit off for a period of time after failed ignition or to use an ignition unit with timer function Preference should be given to using a timer ignition unit 4 1 External ignition units 4 1 1
46. ce life is halved In electronic ballasts these circumstances are far more complicated The mortality rate of individual com ponents the circuit design and above all the electronic load and the temperatures at which the units are oper ated have a considerable influence on the service life behavior This is why the nominal service life of electronic ballasts is stated in combination with a failure prob ability For example all units in the product family POWERTRONIC PTi have a nominal service life of 40 000 hours with failure probability of maximum 10 when operated at the maximum permissible temperatures The service life of electronic ballasts is influenced directly by the temperature at which the units are op erated This is why 2 temperature values are defined to describe the thermal behavior The ambient tem perature t describes the temperature immediately surrounding the unit and thus prevailing around the electronic components To be clear this is not the room temperature or the ambient temperature of the luminaire When an electronic ballast is fitted in a luminaire the real ambient temperature t of the ballast can only be measured with great difficulty and at great effort This is why a second temperature has been stipulated the t temperature Basically this is the casing tempera ture which can be measured by a thermocouple at a set point the t point and is defined as maximum permissible temperature at w
47. ct Lamp electrodes cool down to a lesser extent with the rectangular electronic ballast thanks to the steep electrical transitions through the zero crossing Less cooling down results in reduced sputter effects of the electrodes which in turn means less bulb blackening The more constant and on average slightly higher lamp plasma temperature also produces 3 to 5 more luminous efficacy which also has a positive influ ence in luminous flux behavior in addition to reduced blackening effects Electronic ballasts also have a much faster start up behavior than magnetic ballasts Fig 24 in chapter 4 7 for example clearly shows that a double ended quartz lamp operating with an electronic ballast al ready produces more than 90 of its max luminous flux after approx 40 seconds The same luminous flux level with a conventional ballast takes at least 25 to 30 seconds longer This at least 50 faster start up at the electronic ballast is due to the higher start up current of the electronic ballast producing a higher wattage input into the lamp which therefore heats up more quickly 3 2 3 4 Size weight and handling Electronic ballasts combine ignition component com pensation component and choke in one unit This 3 in 1 Combination clearly reduces the installation workload the risk of installation errors and the need to replace individual faulty units Multi lamp electronic ballasts e g 2x35 W or 2x70 W duplicate these ad vantag
48. curve Because the capacitor for power factor correction is rated for a specific lamp and choke current the power factor varies according to lamp current For an extremely high lamp voltage the choke current is so low that capacitive current exceeds the inductive current and the complete circuit becomes capacitive Under certain conditions audio frequency central con trol systems have to be considered during installation In these cases suitable audio frequency attenuation chokes are to be provided This kind of system is still sometimes used for day night circuits in street lighting although directional radio systems are finding increas ing use here 3 2 Electronic control gear ECG Together with conventional ballasts the use of elec tronic ballasts has meanwhile become widely accepted practice particularly for interior lighting Electronic ballasts offer clear advantages compared to conventional ballasts The main advantages include in particular simplified handling e g lighter ballasts lower energy consumption a positive impact on lamp service life and light quality and last but not least controlled and reliable shutdown of lamps at the end of the service life Basically most of the technical information provided in this manual applies to both conventional ballasts and electronic ballasts This refers for example to wiring requirements wattage reduced operation of MH lamps or instructions for luminaire design B
49. defined by multiplying the physical radiation output with the eye sensitivity curve V A Standard luminous flux measurements only consider the reaction of the eye at high illuminance levels photopic vision as is typical for daylight and indoor illumination Luminous flux measurements measure photopic light as per ceived by the central region of the eye When the illumination level is very low for example at night by star light the vision conditions are said to be scotopic The reaction of the eye changes under these circumstances The eye sensitivity curve for low illumi nation levels less than 0 1 cd m is the V A curve as shown in the figure 43 Sensitivity for red and yellow light decreases while there is better perception of blue light When luminous flux is measured under photopic conditions this does not correspond to what the eye perceives at low light levels The reaction of the eye does not change sud denly from high to low illumination levels The change is gradual when the illumination level decreases to twilight and typical street lighting conditions This is called mesopic vision which lies between photopic and scotopic vision The change in eye sensitivity comes from the presence of two types of light receivers on the retina rods and cones The rods are responsible for vision under low illuminance and are located in the peripheral field of vision The rods are sensitive to scotopic light while the cones react
50. der lamps with their increase in lamp volt age and higher re ignition voltage are more sensitive than unaged lamps The capacitor for power factor correction can act as voltage source during voltage interruptions at least in the short term and extend the time in which a voltage interruption is tolerated before the lamp goes off Voltage interruptions just before the zero crossing are more serious because the plasma has already cooled down significantly 3 5 Stroboscopic effect and flicker Operation of a metal halide lamp on a magnetic ballast under supply voltage with 50 Hz frequency results in periodic fluctuation of the luminous flux with double the supply frequency When the current flow drops near the zero crossing the plasma also has far less radiation But even on passing the zero crossing the luminous flux does not reach zero so that the plasma still has on going radiation The human eye reacts with differing sensitivity to varying flicker frequencies and can for example no longer perceive fluctuations in luminous flux above 100 Hz Literature provides differing ways of depicting the sensitivity of the human eye for periodic luminous flux fluctuations at various frequencies Fig 17 shows an example according to Kelly and Henger 1 When operating at 50 Hz the luminous flux or intensity fluctuates with wattage i e with 100 Hz as shown in Fig 15 Literature uses various equations to evaluate changes in luminous intensity
51. ding filters 2u2020200000n0nnennnnnnnn en nn nn nenn nn nnenenennnnnnn nenn 15 8 2 Brief voltage IHRE JMO eS een ee ee iiaii 16 3 5 Stroboscopic effectand MICK OP eier ee een ee een nee 17 4 lonuUngand staring discharge lamps ee ee een ee reale 19 Al EX terial MNOM ITS ssni i a e a aa aE eu 19 41 1 Paralerigni on Unit erresiren een een AARRE EATA A DAR EAE RENEA Bene 19 Aled Semi parallelignition Unit a ee ee 19 43 Superimposed IJMO sera ee ee nee 20 4 2 AN OOO teeta sincere acts nacre sua E ne ee ae ee ei een ee 20 3 IMOLTE GEN IO Nennen ne ee nn ne ea esse eg 20 4 4 Ignition at low ignition voltage Penning effect usus0suesennnonnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn nn nennen 20 4 5 Ignition at low ambient lemperalures iunesinsne nennen 20 Ao Gape Ga 8121 es 12 C1 o E A ee ee 21 4 7 Start up behavior of metal halide lamps an es nenn anna a an 21 5 Reducing the wattage of high intensity discharge lamps z222220202nenenennnnnnn nn an anno nn nn nn nn nn nnnnnnnnnnnnnnnnnn nenn 23 Sl IVE CCI OT ee ee een ee einer 23 5 2 Wattage reduction TSchnlgkeB nee ee ee 23 2 1 Reducing the supply VONAG 6 sie sis 23 5 2 2 Phase control leading edge trailing edge aussi et este Feiern ae aha 24 5 2 3 Increasing choke impedance or decreasing lamp current r r0s2esenennnnennn nn nenn nnananenennn nn nn nenn 24 5 2 4 Change in frequency for high frequency Mode usus0s0enono
52. due to high re ignition voltage The re ignition peak of a lamp normally increases over the service life and when it exceeds what the supply voltage momentarily can provide there is no re ignition and the lamp goes out see also chapter 6 2 2 Increase of the re ignition peak When operating on a conventional choke the lamp wattage runs through a maximum depending on the lamp voltage see Fig 5 The maximum occurs for a lamp voltage of slightly more than half the supply volt age Near the maximum the lamp wattage changes only slightly with the lamp voltage During the lamp service life the lamp voltage increases as also shown in chapter 6 Lamp lifecycle aging and failure behav ior In order for the lamp wattage to change as little as possible the nominal value for lamp voltage is gen erally chosen near the maximum therefore at about half the supply voltage The impedance of the choke is rated at a certain sup ply frequency and certain supply voltage Deviations from the nominal supply voltage will result in a differ ent ballast curve and a related different working point for the lamp and therefore different lamp wattage To limit the associated greater spread in the lamp para meters a maximum deviation of 5 from the nominal values is permitted in the short term for the supply voltage or maximum 3 in the long term For devia tions over a longer period of time suitable choke tap must be selected Similarly
53. e EMC of the ignition unit 19 20 4 1 3 Superimposed ignitor Superimposed ignition unit Luminaire Capacitor for PFC Fig 21 Simplified circuit diagram for conventional operation of high intensity discharge lamps with a superimposed ignition unit In a Superimposed ignition unit the high voltage is only present at the lamp outputs of the unit Depend ing on cable and structure ignition units of this type can normally take loads of 100 pF corresponding to a lead length of about 1 5 m 4 2 Warm re ignition Normal ignition voltages in the range up to 5 kV do not permit immediate re ignition of a lamp which is still hot The high operating pressures demand ignition voltages of e g 25 kV If a lamp goes out for instance because of a brief interruption in the supply voltage it must cool down for a few minutes for lamp wattages lt 150 W until the falling pressure in the arc tube per mits re ignition for normal ignition units in the 5kV range Higher wattage levels require considerably longer cooling down periods because of the higher thermal capacity The cooling down process depends also on the ambient temperature and the luminaire A narrow hot luminaire prolongs the cooling down pro cedure delaying re ignition of the lamp This cool down time must be considered for ignition units with a timer cut out which are designed to shut off after a certain period of time with failed ignition The design intent ass
54. e lamps fluorescent lamps compact fluores cent lamps high pressure mercury vapor lamps metal halide lamps high pressure and low pressure sodium vapor lamps are not subject to mandatory marking according to the Ordinance on Hazardous Substances 53 54 10 List of abbreviations ACGIH AGLV ANSI CE CIE DALI CISPR ELMAPS EMC EN ENEC ECG ICNIRP IEC CCG LIF LSF LLMF LMF NIOSH PCA RMF SCN WEEE MF ZVEI American Conference of Governmental Industrial Hygienists Arbeitsgemeinschaft Lampen Verwertung Lamp recycling consortium American National Standards Institute Communaut Europ enne European Community Commission Internationale de I Eclairage International Lighting Commission Digital Addressable Lighting Interface communications standard for lighting systems Comite international special des perturbations radioelectriques Special International Committee for Electromagnetic Interference European lamp Manufacturers association for the preparation of standards Electromagnetic Compatibility European standards European Norms Electrical Certification electronic control gear International Commission on Non lonizing Radiation Protection International Electro technical Commission Conventional Control gear choke Lighting Industry Federation Ltd Lamp survival factor as per standard EN 12464 Lamp luminous flux maintenance factor as per standard EN 12464 Luminaire Maintenance factor as per st
55. ectrical engineering is the IEC International Electro down into safety and performance standards While the Technical Commission European standards EN are safety standards stipulate tests regarding electrical usually identical with the IEC standards In addition optical and thermal hazards the performance standards to the contents adopted by the IEC the EN standards look at aspects such as dimensions electrical descrip also include the requirement to withdraw contradict tion luminous flux service life and stipulation of test ing national standards within an appropriate period of procedures time Furthermore safety standards are listed in the low voltage directive which is mandatory for the CE The following table provides an overview of the key symbol and for test marks standards for operating high pressure discharge lamps It features the IEC standards the correspond OSRAM products are constructed according to the ing EN standards bear the same number relevant standards and in compliance with the valid directives 39 40 Table 3 IEC standards for discharge lamps and accessories Discharge lamps excluding 60188 High pressure mercury vapour lamps fluorescent lamps Performance specifications Safety specifications 60192 Low pressure sodium vapour lamps Performance specifications 60662 High pressure sodium vapour lamps 61167 Metal halide lamps 61549 Miscellaneous lamps Bases sockets and gauges 60061 1 Lamp c
56. ed choke characteristic curve The increased watt age input for lamps with already aged arc tube wall can cause increased lamp explosion rates for example Operation in overload conditions will probably cause accelerated aging b The steeper characteristic P U in the range of the normal lamp voltage causes a higher spread of the wattage and therefore of the photometric data e g perceived colour variation We therefore discourage operating the lamps at 277 V supply voltage Our lamps have been developed and undergone service life testing at 230 V supply voltage so that we cannot assume any warranty for the service life behavior and photometric data for any deviating operation Lamp current I in A Lamp power P in W Fig 9 Lamp current I lamp wattage P over the ratio of lamp voltage to supply voltage U U for U 277 V 3 1 2 2 Operation at supply voltage less than 230 V with adapted choke impedance Supply voltages of less than 230 V shift the maximum of the choke curve P over U U Operation at 200 V supply voltage for example is more favorable than at 230 V with regard to the change in lamp wattage with lamp voltage The P U curve runs flatter in the normal range of lamp voltage For lamp voltages exceeding 130 V Wattage falls again N oo oO O O Oo O O n _ N Oo O oO o gt oO Lamp current I
57. eduction in service life 5 2 Wattage reduction techniques The following dimming methods are generally Known by conventional means or electronic ballast e Reduction in supply voltage e Phase control leading edge trailing edge e Increase in choke impedance or decrease in lamp current amplitude modulation e Change in frequency for high frequency operation 5 2 1 Reducing the supply voltage A reduction in supply voltage beyond recommended limits see sections 3 1 2 and 3 1 3 will decrease the lamp wattage Reducing lamp wattage results in de creased lamp voltage and re ignition peak voltage and is generally to a lesser extent than the supply voltage This reduction in the gap between the re ignition peak and the supply voltage makes it more probable that the lamp will go out This applies particularly to aged lamps where the lamp voltage and re ignition voltage have already increased Fig 25 shows as an example the behavior of certain lamp types on reducing the supply voltage Here the ratio of re ignition voltage to effective supply voltage U s U has been standardized to 1 for 220 V supply voltage It can be seen that when the supply volt age decreases this ratio generally assumes values of greater than 1 This also means that the gap between ULS US referred to the ratio at 220 V A HCI TM 250 W WDL Y HCI TS 70 W WDL HCI TT 150 W WDL Bl HQI TS 150 W WDL HQI TS 150 W NDL ULS US referred to the
58. een When plastic screens are used it is important to ensure that the hot parts of the lamp will not melt or set fire to the screen should the lamp burst The cover screen must be both resistant to tempera ture change and break proof 6 3 9 Rectifying effect High intensity discharge lamps can assume an asym metrical mode rectifying effect There are various possible causes e Differently heated electrodes This is typical when the lamp starts but is nor mally only short lived The DC component sends the choke into saturated state the magnetic resistance decreases and current is limited to a lesser extent shown as an example in Fig 32 This effect is described in the standards as in rush current IEC 61167 Malfunction of one of the electrodes This can be caused by differently worn elec trodes or in rare cases by a broken electrode The result is longer asymmetrical lamp current or if an electrode has broken off a permanently asymmetrical lamp current 29 30 The effects are similar to rectifying effect at the e Discharge in the outer bulb start but the longer persistence can cause over As the leads are not geometrically the same the heating of the choke and ignition unit discharge generated between them can be asym metrical with the effects described above Lamp Voltage Lamp Current IM ii UT y GANA
59. eepage and clearance distances required in the socket standards IEC 60238 or EN 60238 VDE 0616 Part 1 In the same way the other base systems are subject to the socket standards for special sockets IEC 60838 1 or EN 60838 1 VDE 0616 Part 5 CAUTION Do not use sockets for incandescent lamps e g E27 or R7s Sockets for discharge lamps must be used to handle corresponding ignition voltage e Temperature code Txxx continuous use temperature This is the highest temperature for which the socket was designed The temperature of special holders is measured at the socket contact ac cording to 60838 1 all holders for high pressure discharge lamps except Edison sockets If the heat resistance of insulation terminals and leads deviate from this temperature limit then sepa rate limit values are stated In the case of Edison sockets according to IEC 60238 the rated temperature is valid for every point in and on the socket At the end of the lamp service life higher tem peratures than normal can occur in the pinch area caused by outer bulb discharges The socket must be rated accordingly see also chapter 6 2 1 Leak ing arc tube When replacing such lamps the socket must always be checked for signs of damage and re placed if necessary because a damaged socket would also damage the new lamp e Rated current and rated voltage The socket must be chosen according to the lamp parameters The rated current in this case
60. elatonin The course of the sensitivity curve measured by Brain ard for melatonin suppression shows no correlation to the course of the previously mentioned eye sensitivity curves for the red green or blue photoreceptors in the eye This made it apparent that there is a further previously unknown type of light sensitive cell in the eye respon sible for the circadian effect of light Prof Gall from the Lichttechnisches Institut at the University of IImenau has recognized that the sensi tivity curve for melatonin suppression published by Brainard is very similar to the known curve V A which describes eye sensitivity for seeing brightness Only the spectral position is shifted towards blue The curve C A suggested by Gall serves today as the foundation for a measuring system for circadian light ing data defined in DIN V 5031 100 These weighting factors can be taken into account in order to consider the biological effect of light sources Circadian function visual sensitivity 1 gt bd m c T a Ee S Q 0 380 420 460 500 540 580 620 660 700 740 780 wavelength nm Fig 54 Definition of a circadian function C A by Gall et al in analogy to the photometric function V X as standardized by the CIE 8 4 UV radiation The metal halide lamp standard IEC 61167 describes the effective UV radiation output and
61. es because to connect to 2 luminares only one power lead is required Electronic ballasts are also lightweight They weigh 50 to 60 less than magnetic ballasts which of course offers direct advantages in terms of luminaire design they can be sleeker in structure a wider range of materials can be used and a lighter load can be placed on the fastening components 3 2 3 5 Bidirectional data transfer Intelligent electronic units will in the future offer com pletely new possibilities of controlling and monitoring lighting systems thanks to bidirectional data transfer Features such as querying the lamp or ballast status integration in Building Management Systems BMS and central or local actuation and management of lighting solutions will not only bring a clearly expanded range of functions but also optimize maintenance and repair work In the medium term it is quite conceivable to see developments here similar to those in low pres sure discharge technology e Electronic ballasts are state of the art e Electronic ballasts can be used to achieve significant increases in quality reliability and safety of lighting systems with metal halide lamps e Most new MH lighting installations today are already equipped with electronic ballasts 3 3 Influence of harmonic waves and corresponding filters The development of modern semiconductor technology with a significant increase in the number of consum ers with solid state switc
62. gaps in the spectrum particularly in the blue part of the spectrum which is responsible for the poorer colour rendering compared to the metal halide lamp mmm NAV T 400W SUPER 4Y VAA en HCI TC 70W NDL V A m m V A V A oO o1 q E Lam te p 2 _ 2 N o Weighting factor for eye sensitivity curve Fig 48 Relative luminous flux in lumen per 1000 Im and per 5 nm In Fig 49 the radiation output has been multiplied by Illumination levels in street lighting are higher than the V A curve for illumination levels below 0 1 cd m 0 1 cd m resulting in a sensitivity between photopic The diagram shows that the perceived illumination and scotopic vision level of the metal halide lamp is far higher in this ex ample about three times higher than the high pressure sodium vapor lamp mm NAV T 400W SUPER 4Y V A mmm HCI TC 70W NDL V A AAN m m VA oO O1 2 Im 5nm 1000Im O Weighting factor for eye sensitivity curve Fig 49 Equivalent to luminous flux taking account of an eye sensitivity curve at a low illumination level V N 47 48 8 2 Colour rendering Colour is a sensory impression conveyed by the eye The evaluation of a colour stimulus by the eye causes a uniform effect colour stimulus spec
63. ght considerable advantages The possibility of further increasing the wall temperature improves luminous efficacy and colour rendering The absence of the thick plug at the end of the tube re duces light absorption in this area resulting in a higher luminous flux with more uniform irradiation character istics There are fewer differences in the wall tempera ture between the various burning positions and there fore also smaller differences in colour between the burning positions The reduced ceramic mass of the round tube enables the tube to heat up faster reaching the photometric values more quickly Similarly when the lamp goes off warm re ignition is possible more quickly because the required cooler starting tempera ture for normal ignition devices is achieved faster The uniform wall thickness and round shape produce a more even temperature curve along the inner tube wall as shown in Fig 3 based on the temperature shown in colours diagram The steeper temperature gradient in the cylindrical ceramic favors chemical transport pro cesses During this process aluminum oxide ceramic dissolves in the liquid metal halide melt and settles at cooler points of the arc tube If erosion from the wall goes too far this can lead to leakage in the tube causing the lamp to fail Failures due to so called ceramic corrosion are thus less likely to occur in lamps with round ceramic tubes Convection Convection Solution of
64. h induced voltages Lamps with gas filled outer bulb for supply voltages of 400 V can form an arc when a lead is broken or a weld comes loose Due to the current limiting choke this arc can persist for a longer period of time and cause the lamp to burst Such arcing occurs both in lamps with an ignition unit and lamps with auxiliary starter electrode lamps for ignition at supply voltage with a wattage of 2000 W 6 3 4 Leaking outer bulb Mechanical impacts can cause the outer bulb to leak so that air penetrates Given the high temperatures leads oxidize when oxygen is present causing an open in the circuit This is a non critical fault the lamp no longer ignites Ignition units without cut out can however fail prematurely due to permanently generat ing ignition pulses 6 3 5 Lamps that do not ignite This can result from open electrical connections within the lamp or extreme aging and is actually a non critical fault Ignition units without cut out can however fail pre maturely due to permanently generating ignition pulses 6 3 6 Breakage or differing wear of the electrodes Breakage of an electrode or differing wear in the elec trodes with choke operation can cause a flow of asym metric current with DC components which can result in the choke overheating This effect of asymmetrical conductivity is dealt with in greater detail below A broken electrode in a ceramic lamp can cause leaks in the arc tube as a result of o
65. han the stated limit values it is possible for the arc tube to overheat when the stated limit values for the outer bulb are exceeded with the following effects e change in colour properties e leaking arc tube e blackening of the arc tube and deterioration in luminous flux maintenance The outer bulb temperature is only an indirect indi cator for arc tube load Outer bulb and arc tube are coupled by radiation and to a small extent by thermal conduction via the leads While it is important to limit the outer bulb tempera ture it is worthy to note that an inadequately designed reflector can still cause the arc tube to overheat with out any major change in the outer bulb temperature see also chapter 7 9 Optical design of reflectors One indication that the design of a luminaire is in sufficient comes from comparing the lamp voltage measured when burning freely outside the luminaire and inside the luminaire after being left long enough to stabilize The increased lamp voltage measured in lamps lt 400 W in the luminaire should not exceed 5 V There is no notable difference in the lamp voltage inside the luminaire for lamps with wattage input gt 1000 W outer bulb and free burning operation But soiling of the outer bulb caused by evaporation from luminaire components can cause the lamp voltage over its service life to increase more than in free burn ing operation This increase depends on the level of surface soiling i
66. her discharge lamps High pressure mercury lamps These lamps can be dimmed to 50 of the rated wattage whereby they must be started up with 100 wattage Dimming is possible by voltage reduction phase control and amplitude modulation High pressure sodium lamps It is possible and allowed to reduce the power of all VIALOX NAV down to 50 of the lamps rated values without impact on the service life e via step switching by changing to inductive control gear with the next lower rating or e via step switching with additional inductance whereby in both cases electronic power switches must be used When reducing the power ensure that the lamps are started and operated at their rated values for approx 10 minutes before dimming It is not permitted to reduce the power by leading edge phase control or reducing the mains voltage OSRAM recommends the electronic ballast POWERTRONIC PTo for dimming operation 29 26 6 Lamp service life aging and failure behavior 6 1 Lamp service life and aging behavior All lamp specific electrical and photometric data are ascertained after operating for 100 hours under labo ratory conditions using reference ballasts according to IEC The service life data are determined under con trolled laboratory conditions with a switching rhythm of 11h on 1h off In practice noticeable deviations can occur due to deviating supply voltage ambient tem perature and other general conditions For met
67. hes and converter controllers unfortunately results in undesirable side effects on the AC voltage supply by causing considerable inductive wattless power and non sinusoidal current A typical converter current consists of various super imposed sinusoidal partial currents i e a first harmonic with the supply frequency and a number of 19 16 so called harmonic waves whose frequencies are a multiple of the supply frequency in three phase sup plies these are mainly the fifth seventh and eleventh harmonic waves These harmonic waves increase the current of the ca pacitor for power factor correction as the reactance of a capacitor decreases with increasing frequency The increasing capacitor current can be accommodat ed by improving the design of the capacitor but this does not eliminate the risk of resonance phenomena between the power capacitors on the one hand and the inductance of the feeding transformer and the grid on the other If the resonance frequency of a resonance circuit consisting of power capacitors and inductance of the feeding transformer is near enough to the frequency of a harmonic wave in the grid this resonance circuit can amplify the oscillation of the harmonic waves and Cause immense overcurrent and overvoltage The harmonic wave contamination of an AC voltage supply can have some or all of the following effects e early failure of capacitors e premature triggering of protective switches and o
68. hich safe operation of the electronic ballast is still guaranteed In addition the t temperature is set in relation to the ballast service life That means that the measured t temperature permits very precise conclusions as to the anticipated service life of the electronic ballast OSRAM s HID electronic ballast for example principally reaches its full nominal service life at the maximum permitted t temperature In practice this means that any temperature levels below the t temperature always prolong the effective service life As a rule of thumb it can be presumed that a temperature 10 C below the printed maximum t temperature will double the service life of the electronic ballast However it is not advisable to use only the absolute maximum tolerable t value for conclusions regarding the quality and service life of an electronic ballast This is because on the one hand the position and therefore indirectly also the value of the t point can be freely defined by every electronic ballast manufacturer On the other hand the rule of stating the nominal service life at the maximum permitted t temperature has not yet become established throughout the electronic ballast industry In practice this means that many electronic ballasts only achieve approx 50 of their nominal service life at maximum t temperature Nominal service life B10 max 10 of the electronic ballasts have failed A serious evaluation of the electronic ba
69. high temperatures It is up to the user to make an appropriate selection and to ensure that the lamp holders are installed correctly according to the corresponding regulations e g IEC 60598 VDE 0711 IEC 60335 VDE 0700 Sockets consist of several parts each with their own function limits Exceeding these limits causes premature failure of the sockets Temperature and ignition voltage are critical be cause the effects of exceeding the limit values are often only detected after a longer period of time This results in a sudden not gradual decrease in service life Please note that lamps vary in wattage permitted up to 12 and temperature and that according to IEC 60926 ignition units may generate output voltages of up to 30 above the nominal value e Ignition voltages The socket must be rated for the corresponding ignition voltage When mounting the socket and the supply leads in the luminaire it is important to consider the re quired creepage distance and clearance as well as distances in the insulation The luminaire IEC 60598 1 standard corresponding to EN 60598 1 defines the safety requirements for ignition volt age regarding creepage and clearance distances Particularly when using high pressure discharge lamps with Edison bases E27 and E40 care is required to ensure that the sockets are approved for discharge lamps Suitable sockets are marked with the value to max 5 kV and comply with the increased cr
70. hs that are fitted in warmer zones outside the luminaires 4 6 Cable capacitance The capacitance of the supply cables between lamp and ignition unit depends on various general condi tions These include the size and structure of the cable diameter distances and insulation together with number of individual cables dielectric coefficients of the materials The capacitance also depends on the grounding and shielding of the cable and where it is fastened e g close to grounded surfaces Commonly used power cables are not suitable for this purpose because of their relatively thin PVC isolation where the wires lie comparably close together The capaci tance here is about 100 pF m Because of the high ignition voltage for discharge lamps the lead wires have thicker insulations and they are normally not placed close to each other The capacitance of the lead wires will therefore be lower than for the power cable Capacitances only form limited resistance to high frequency voltage components of the ignition pulse The capacitance attenuates the ignition pulse with resulting ignition pulses possibly not reaching the amplitudes required to ignite the lamp Certain load capacitances must therefore not be exceeded de pending on the specifications of the ignition unit after 20s after 80s 70 T 5200K CRI 70 amp 90 T after 40s amp 1 T 4100K CRI 66 10 T 5600K CRI 29 40 T after 100s 4200K CRI 8
71. ification This can be described by colourimetric numbers e g x y and z in the CIE 1931 or CIE 1976 colour space or L a and b in the CIE 1976 L a b space or W U and V in the CIE 1964 colour space W U V But the perceived colour the subjective impression depends on the general conditions colour mood surrounding surfaces luminance The primary colours i e saturated monochromatic co lours run around the periphery of the colour triangle An ideal black body or Planck radiator radiates an electromagnetic spectrum depending on its tempera ture The colour thus depending on temperature is depicted in the Planck curve this is the so called colour temperature Colours on the Planck curve are marked with the corresponding colour temperature chromaticity coor dinates deviating only slightly from the Planck curve within the range of the Judd straight lines corre sponding to a distance of approx 5 4 threshold value units are marked with the correlated colour temperature One way of showing the colour impression is the stan dard chart as per DIN 5033 basic stimulus Fig 50 Standard colour chart as per DIN 5033 Reference color temperature 4000K HQL Standard R 46 R 61 R 54 R 46 CRI 50 R 43 Re 36 R 66 Rs 44 HCI NDL R 99 R 97 R 88 R 96 R 97 Re 95 R 96 Rz 93 Fig 51 Defining the colour rendering indices in comparison for two light sou
72. ing discharge lamps at electromagnetic ballasts Inductively stabilized discharge lamps achieve power factors of only about 0 5 because of the dephased current flow The power factor of a load is defined as the ratio of effective power to the apparent power actually withdrawn from the grid kW to kvar and is referred to as cos The apparent power comprises the effective power used by the consumers to create e g heat or mechanical energy and the idle power that is used to develop magnetic or electric fields of inductivity and capacity However the latter flows back into the grid after a half cycle length i e it is not actually used The closer cos w is to one the smaller is the share of wattless power withdrawn from the grid A higher share of wattless power results in a higher flow in current for which the supply lines have to be rated Similarly power dissipation in the supply lines increases in a square progression with the current In order to achieve the values demanded by the utility com panies of more than 0 85 a grid parallel capacitor must be selected according to the lamp or choke current to approximately correct the shift in phase By including an exactly calculated capacitor the inductive wattless load required by an electric consumer can be offset with a Capacitive wattless load It is thus possible to reduce the wattless power withdrawn from the grid this is called the power factor correction or wattless power compens
73. ing position Reflector neck temperature in base up burning position 7 1 3 9 HQI TS long arc and short arc 1000 W Pinch temperature in horizontal burning position Outer bulb temperature in horizontal burning position Measurement with radiation pyrometry 7 1 3 10 HQI T 1000 W Base edge temperature in base up burning position Outer bulb temperature in base up burning position Outer bulb temperature in horizontal burning position ae par a 14 Base edge temperature in horizontal burning position 7 1 3 11 HQI TS Excellence Pinch temperature in horizontal burning position The temperature limits for lamps where only one burning position is permitted are determined in the allowed burning position 35 36 7 2 Influence of ambient temperature on ballasts and luminaires As the ambient temperature increases the tempera ture of the luminaire components also increases at the same rate The lamp reacts to a higher ambient temperature with an increase in lamp voltage and lamp wattage This can accelerate corrosion and aging processes An increased re ignition peak can result in failure by the lamp going off at an earlier point in the service life Higher temperatures at choke and ignition unit mean a reduced service life for these parts or also earlier failures The limit temperatures for chokes is generally 130 C and 70 C to 1
74. ions from the room surfaces Luminaire characteristics Reflector type Lamp type Ballast Operating hours per year Maintenance interval Luminaire Maintenance interval Lamp Failed lamps are replaced immediately Normal every 2 Years medium Room index 1 1 lt k lt 3 75 direct B Reflector open at the top Metal Halide lamp CIE CCG 3000 every 2 Years every 3 5 Years Yes 0 61 Maintenance factor Maintenance instructions Lamps must be replaced with suitable replacement lamps of the same characteristics luminous flux light color color rendering Any existing starters should also be replaced during relamping The room and surfaces deflecting light are to be maintained so as to preserve the original reflection characteristics Always comply with the manufacturer s cleaning instructions Measures to comply with a required minimum light ing level include regular cleaning of the room and the luminaire as well as timely replacement of the lamps Timely replacement of the lamps also ensures avoid ance for the most part of undesirable effects at the end of the lamp service life When compiling the maintenance plan consideration must be given to the decrease in luminous flux over the course of the lamp service life in the form of the lamp luminous flux maintenance factor LLMF The CIE has stated a general luminous flux curve for metal halide lamps which results in a maintenance fac
75. is the highest continuous load current and the rated voltage is the highest voltage for which the socket is designed CAUTION Certain sockets such as G12 and E27 are used for different wattage levels When insert ing or exchanging lamps make sure that the right lamp for the respective ballast is chosen Other wise the lamp is operated incorrectly and the socket may possibly not be rated for the deviating operating conditions e Fastening parts The connection parts e g blade terminals must be chosen according to the requirements e g temperature current load corrosion resistance Connection leads The connection leads must be rated accordingly for the conditions of use with regard to heat and UV resistance mechanical strength electric strength and current carrying capacity PTFE leads are normally not suitable to handle ignition voltage In practice silicone insulated leads with 3 6 mm outer diameter have proven effective for discharge lamps For lamps with im mediate hot re ignition silicone insulation 7 mm thick should be used together with fiberglass inlay While the lamp is starting up it is possible for the start up currents to briefly exceed the nominal values which must be taken into consideration when rating the socket Up to 1 5 to 2x the oper ating current can flow during the start up phase within the first 5 minutes of operation Isolation of Contact Connections Care must be taken to electrically
76. ition cut out Only with timer ignition units Ignition time limited to 18 min Up to 30 longer depending on lamp type and kind of use Up to 50 faster Light flicker Visible flicker Flicker free thanks to 165 Hz operation 3 over the entire service life regardless of fluctuations in temperature and supply voltage or lead length Consistent wattage Increase in wattage over service life also dependent on fluctua tions in temperature and supply voltage and on lead length 3 components complicated 1 unit simple wiring wiring Size and weight Heavy several components large Light and compact in some cases Power factor correction PFC 0 5 0 95 considerable aging gt 0 95 fluctuations Noise development Clearly audible humming possible Almost noiseless Bidirectional data exchange Not possible Generally possible 14 The main advantages of electronic ballasts are described in greater detail in the following section 3 2 3 1 Reducing energy consumption Compared to conventional ballasts electronic ballasts can considerably reduce energy consumption over the service life The energy savings result from two factors 1 Unit power dissipation In conventional ballasts a large amount of energy is lost in dissipated heat on account of the design By contrast electronic ballasts have a low loss design with top quality components reducing dissipation to less than 10 of the nominal power 2 Increase in wattage
77. l period of light exposure Old wall carpets for ex ample which have been exposed to light for centuries show hardly any remaining sensitivity to radiation Fading occurs not only due to UV but also with short wave visible light depending on the spectral object sensitivity effect function of the irradiated object There is plenty of information on this subject in the Division 6 report of the CIE CIE technical collection entitled On the Deterioration of Exhibited Objects by Optical Radiation Although this deals with objects in museums the results are also applicable for example to shop window lighting A stronger fading effect could be achieved by stronger focusing of the light or by a higher luminous flux in the lamp A numerical definition of colour change generated by irradiation must be expressed in the form of colouri metric differences AE In this way it is possible to express exactly every fading blackening and yellowing or basically every colour change Effective radiation resulting in a colour change of exactly AE 1 is called threshold effective radiant exposure This value is important as experience shows that colour changes in this magnitude can be perceived by the average observer on comparing unexposed areas of a sample with exposed parts Other limit values can be used AE 2 3 4 etc if the correspondingly larger colour differences are acceptable 8 4 2 Protective measures to reduce fading
78. learly reduce the service life Operation at reduced wattage also causes increased tube blackening as explained in chapter 5 Reducing the wattage of high intensity discharge lamps 6 2 Storage of metal halide lamps Incorrectly stored lamps e g damp and warm may suffer corrosion on the contacts after a while this oxi dation must be completely removed before the lamps are used In unfavourable conditions this may even result in ignition problems Lamps with filler material may lose this filler material if stored incorrectly and the socket contacts may then become exposed There is a risk of arc overs during the ignition process or the risk of touching live parts 6 3 Failure mechanisms of metal halide lamps The following failure mechanisms are possible for metal halide lamps and the probability increases as the lamp gets older e Leaking arc tube e Increase in re ignition peak finally the lamp goes out e Broken leads e Leaking outer bulb e Ignition failure e Breakage or wear of the electrodes in the arc tube e Scaling of the base contacts by arcing in the socket e Bursting of the lamp Glow discharge Fig 29 Various states of outer bulb discharge 6 3 1 Leaking arc tube High temperatures and pressures in the arc tube the aggressive chemical substances in the tube and the thermal cycling of a lamp place extreme strains on the arc tube This can cause the tube to leak allowing starting gas and filling
79. llast service life is only possible by comparing the electronic ballast ambient temperature t with the corresponding service life Comparison of the service life using only the t temperature is not appropriate 3 2 3 Advantages of operation with electronic ballast POWERTRONIC PTi The following table provides an overview of the advan tages of operating lamps with the electronic ballast The corresponding values and statements are based on tests and experience with POWERTRONIC PTi ballasts so that they cannot necessarily be transferred 1 1 to ballasts of other makes In comparing the conventional and the electronic ballast the performance of the conventional ballast constitutes the reference parameter and is given a value of 100 This is also based on the fact that the lamp parameters are defined with the reference conventional ballast For more details please refer to the POWERTRONIC Technical Guide Electronic control gears for metal halide lamps 13 En Magnetic ballast Electronic ballast POWERTRONIC Energy consumption 100 10 to 15 savings over the service life Lamp start up Depends on type usually approx 60 to 90 sec to reach 90 of the luminous flux level Colour stability Colour variation possible Clearly reduced scattering initial and over service life Cut out at end of lamp service Not available or only simple Permanent parameter control life cut out mechanisms intelligent cut out mechanisms Ign
80. maximum possible lamp wattage To cov er all possible parameters such as choke impedance spread of lamp wattage and supply voltage tolerance Lamp wattage should be set to approximately 20 above the normal wattage for measurement purposes The operating temperatures of a lamp differ according to the burning position The worst case operation is the base up burning position for pinch or base edge temperature measurements and the horizontal burning position for the outer bulb temperature measurement insofar as this is possible with the permitted burning positions Temperature measurement lamps prepared with ther mocouples are available from OSRAM on request for a fee 33 7 1 3 1 HCP TC G8 5 7 1 3 4 HCI E and E P HQI E27 and E40 7 1 3 2 HCI T HQI T G12 similar for the HCI TM and HQI TM G22 Pinch temperature in base up burning position Outer bulb temperature in horizontal burning position SZ 7 1 3 3 HCIP TF GU 6 5 Pinch temperature in base up burning position Outer bulb temperature in horizontal burning position 34 4 IT k Y 7 1 3 5 HCI T and TT HQI T E27 and E40 7 1 3 6 HCI TX P 7 1 3 7 HCI TS RX7s RX7s 24 and HQI TS Fc2 Outer bulb temperature in horizontal burning position Pinch temperature in horizontal burning position 7 1 3 8 HCI PAR E27 Base edge temperature in base up burn
81. mediate circuit The immunity of the PTi input stage to line related interference is safeguarded by tests according to the IEC 61000 standard Such line related interference includes e g e burst as per IEC61000 4 4 1000V peak repetition frequency 5kHz low energy pulse e current feed as per IEC61000 4 6 frequency range 0 15 80MHz 3Vrms e surge as per IEC61000 4 5 1000V symmetrical 2000V asymmetrical high energy pulse e voltage interruptions as per IEC61000 4 11 e voltage fluctuations 3 4 Brief voltage interruptions When the lamp current falls the recombination rate starts to exceed the ionization rate causing a reduc tion in plasma conductivity This occurs with magnetic ballasts in every half wave on passing the zero cross ing and results in the so called re ignition peak When recombination of the charged particles has progressed far enough the remaining quantity of charge carriers is not sufficient enough to generate an adequate quan tity of new charge carriers when the voltage increases again the lamp goes out The high pressures in the arc tube mean that the ignition voltage is now no lon ger sufficient to re ignite the lamp It has to first cool down for a few minutes before it can ignite again see also chapter 4 2 Warm re ignition When the supply voltage is interrupted both the length and depth of the interruption 100 for complete interruption and the phasing of the interruption are important Ol
82. n nun nenn nennen 32 7 1 1 General physical conditions for temperature limits for outer bulbs and pinches in metal halldelamps unsern 32 7 1 2 2 Measurement with tnerfmocouple u nnnnne nennen en 32 7 1 3 Measuring points for thermocouples in different lamp types 22202002420200000n nn en nn nennen nenn 33 7 2 Influence of ambient temperature on ballasts and luminaires us0z2u202000020e0 no non nn nenn nennen nennen 36 7 3 Lamp ROET ass anna anne ee ee ee see ee ee 36 Ta Cond 19 UA acliicc ee eb A ee ae nT een eer E eee eee rere 37 7 5 Maintenance of lighting systems with metal halide lamps uu u444440en en en onen nn nennen nenn nennen nn nn nn 37 7 6 Standards and directives for discharge lamps au u u u nun en 39 Ol or NA a E ee ee ee E een ee 39 PTO DIRECT ee seca Eee ee 41 COS Gormo ANS aa A E E ee ee 41 ef n MVC OU CIN ses en sine han pe Een ee nee een neben 42 7 8 ROM COMON zus ee ea er ee une 42 l3 Qpticaldesign OF Ui CCVOl rennen 42 79 1 Condensalion on the TT pe een lee ion leere 42 1 9 2 Projection of the condensate nee ee ee eiserne 42 7 9 3 Back reflection Ondthelamp mn aan rear ee ee 43 8 CON and CO OU ee a ee ee erg 43 8 1 INOUE VS e AEE ee A AE AE ee ee ee re 44 92 COMOUl LEN S GING scan tcnoncrancsaomscanttaccsubiatan a aN Ea ea A NEER 46 82 1 Testcolo rs from standard DIN BIO ee ee ee 47 8 2 EIOHL An CUI OL II nee ee ee ee ee ee ehe 48 ee UY este
83. n the lamp and can therefore not be put in figures To avoid this effect it is recommended to use temperature and UV resistant materials in the luminaire Outer bulb Radiation Capillary Fig 33 Diagram to show thermal coupling of arc tube and outer bulb 7 1 2 2 Measurement with thermocouple Measurement with thermocouple is a simple practical method of obtaining measured values Fig 34 Affixing the thermocouples to the outer bulb and the lamp base Fig 35 Clamping the thermocouple on the outer bulb using a spring element Please adhere to the following to properly measure with a thermocouple e Good contact with the surface being measured e Low heat dissipation from the connection point and therefore thermocouple wire with a small diameter thermocouple wire parallel to the surface being measured e When measuring the outer bulb temperature corresponding evaluation must consider the radiation cooling down curve The radiation of the arc tube heats up the thermo couple on the outer bulb above the temperature of the quartz glass on which it is positioned Because of the low thermal capacity the thermocouple cools down quickly to the temperature of the quartz glass after switching off the lamp and then cools down slowly with the quartz as shown in Fig 36 and Fig 37 The flat part of the cooling curve can be extrapolated back to the switch off point to ascertain the temperature of the outer
84. n the supply voltage must first be stepped up A good way of doing this is use an autoleak trans former Part of the secondary windings act as lamp choke On the one hand this saves on material and on the other hand a higher voltage open circuit voltage is available to start the lamp These types of ballasts are typically more economical than a constant wattage style ballasts at the expense of wattage regulation Coro PFC capacitor La lamp U supply voltage Tr autoleak transformer Fig 7 Autoleak transformer 3 1 1 2 Constant wattage ballast A constant wattage ballast such as those widely avail able in the USA consists of an autoleak transformer in series with a capacitor The advantage of this circuit is the reduced impact of fluctuations in the supply volt age and the possibility of operating the lamp at supply voltages 110 120 V in the USA 100 V in Japan that lie within the range of the lamp voltage C capacitor La lamp U supply voltage Tr autoleak transformer Fig 8 Constant wattage ballast 10 3 1 2 Variation in supply voltage for adapted inductance Some countries have supply voltages that permanently deviate from 230V When using correspondingly adapt ed inductances the following points must be taken into account 3 1 2 1 Operation at supply voltage higher than 230 V with adapted choke impedance An increase in supply voltage shifts the maximum of the choke
85. nd of the lamp service life The ignition time limit ensures that old lamps where stable operation is no longer possible are not subject to endless ignition attempts After max 18 minutes and precisely defined ignition intervals the POWERTRONIC ECG cuts out automatically If a lamp goes out 3 times the electronic ballast also cuts out This avoids interfering flickering light prevents EMC load on the cables and also an excessive load on the electronic ballast itself Permanent monitoring of parameters such as lamp voltage or lamp current by the integrated micro con troller and alignment with pre defined nominal values also makes it possible to turn lamps off well before they reach critical or undefined conditions which often can hardly be managed 3 2 3 3 Light quality light colour drop in light output start up HID lamps with electronic ballasts offer considerably improved colour quality both when initially installed and throughout the service life The constant wattage supplied to the lamp by the electronic ballast can compensate for differences in light quality resulting for example from production tol erances or differing aging states The result is visibly more even light colour and a more uniform chromatic ity coordinate Similarly supply voltage fluctuations or the length of the power leads are no longer relevant when using an electronic ballast as the constant wattage supply to the lamp means these have no effe
86. nition units with time cut out The use of electronic ballasts is beneficial if the electronic ballast has a corresponding cut out mechanism It is wise not to operate metal halide lamps right up to the end of their natural service life but to replace them at the end of the economic life This is appropri ate because the luminous flux decreases noticeably on exceeding the economic life and the probability of undesirable effects increases at the end of the service life Lamps should be replaced before reaching the economic life if e the light colour of the lamp changes noticeably e the luminous flux decreases considerably e the lamp will not ignite e the lamp goes on and off intermittently cycling On complying with all safety measures metal halide lamps are safe to operate and provide a brilliant efficient light 31 32 7 Luminaire design and planning of lighting systems 7 1 Measuring temperatures ambient temperature 7 1 1 General physical conditions for temperature limits for outer bulbs and pinches in metal halide lamps When the limit values for pinch temperature or outer bulb temperature for hard and soft glass are exceeded the following can be expected e the foil oxidizes e the evacuated outer tube collapses and the gas filled outer tube blows out when the glass turns soft e the cement in screw base lamps crumbles Although quartz glass can withstand far higher temper atures t
87. nnnnnnnnnnanennnnnnnn nennen nenn nennen en annen 24 5 3 Recommendations for reducing the wattage in discharge lamps usu2u2sennonnnonnnnnnnnnnnnnnnnnnnnnnnnnnnn 25 99 1 Metal halde lampe a ana ee ee ee 25 5 3 2 Dimming for other discharge lamps essen ee een Bene 25 6 Lamp service life aging and failure behavior scscuecesenetacdesesasaseeusse nse aucrqanetadeeseeddamoseus sewnttncaqeuestnes denneane uonebiages 26 6 1 Lamp service life and aging behavior anne ee ee ee ee 26 6 2 SIOr 29207 metal halide TADS cates ete tte cee hecsnnea teetawast santo seat AE PEATE AERE NEn E AEn EAEan ennie NENN 26 6 3 Failure mechanisms of metal halide lamps u euere 26 2321 MI E Ue en nn e Bee nee een a ee ee E A 27 6 2 INOLSASEANTE GENION POS seen ernennen 27 6 3 3 Broken lead or broken weld aa ee are een 28 8 2 2 LEBER OUTO DUD se een een a ee AEAT ter A Beheben 28 ideo EAN DS WAL CO MOU TOM ame ee ea een ea Ruten Denen nee ern nee ange 28 6 3 6 Breakage or differing wear of the electrodes 2usen0n0nnnnnnnnnnnnnnnnnnnnnnnen nn nn nenn nnananenennnnnnnnnnnnnn 29 6 3 7 SEAUING OL the Dace SOCKET eier ua een 29 SIO Ne ale ene ee ee een 29 0 39 FECUNDO CMC nen ee ee ee een ee 29 0 09 10 One USON ee ee ee een ee ee een eelanese 31 7 Luminaire design and planning of lighting Systems ee er ee ner ae eh ee 32 7 1 Measuring temperatures ambient temperature u2u20220202000n0nnn nn non nn anno nenn anne nenn nn nen
88. particles to enter the outer bulb Depending on the size of the leak this effect is usually a gradual process It is initially noticed by a consider able change in the light colour Increasing leaks of starting gas into the outer bulb can result in the dis charge process moving from the arc tube to outer bulb discharge For lamps with evacuated outer bulb various ab normal discharge states can occur depending on tube filling pressure and outer bulb volume For lamps with gas filled outer bulb usually lamps gt 400 W glow discharge and incandescent mode do not occur Particularly in lamps operat ing with ignition units the described faults result in a direct arc discharge In extreme causes this can cause the lamp to burst In the case of glow discharge the voltage across the lamp is high but only very low current Sputtering Causes material to be deposited on the outer bulb It is possible for glow discharge to precede arc discharge The temperatures in the pinched area are lower than in normal operation In the case of arc discharge the voltage across the lamp is low and the current is limited by the choke The attachment of the arc onto the leads in the outer bulb can cause these to melt The high temperatures cause the material of the leads to evaporate and then settle on the outer bulb The hot arc near the pinch ing area can result in high temperatures in extreme cases they can exceed 800 C At the contact be
89. permits higher wall temperatures thereby evaporating more of the metal halide salts into the gas arc and allowing for more efficient use of the chemicals Ceramic lamps offer improved luminous efficacy and colour rendering as a result Ceramic arc tubes can be produced with smaller dimensional tolerances reducing the variation in light technical and electrical parameters Ceramic is less susceptible to attacks from the ag gressive metal halide filling and is less permeable for filling particles resulting in a considerably longer service life compared to quartz tube lamps Ceramic arc tubes are now available in various different forms the original cylindrical version and the improved round version 2 2 1 1st generation cylindrical form In the first version the ceramic arc tube was designed in a cylindrical form based on the production technol ogy for the high pressure sodium lamp The arc tube was made up of cylindrical sub sections sintered to gether The arc tube consisted of a relatively thick plug at either end of the tube this was necessary for the durability and functioning of the tube 2 2 2 2nd generation freely moldable ceramic POWERBALL A second step with changed production technology permitted production of freely moldable tube geo metries This made it possible to produce round ce ramic arc tubes with a constant wall thickness the POWERBALL arc tubes The round form and constant wall thickness brou
90. rare for ceramic metal ha lide lamps the probability is greater in lamps with a very old quartz arc tubes With progressing age the quartz crystallization increases making it brittle How ever the lamps normally fail by going out During operation the arc tube is under great pres sure When the arc tube bursts fragments can fly at great speed destroying the outer bulb when they hit it When the outer bulb is broken after the tube has burst very hot fragments of the arc tube come into contact with the luminaire OSRAM therefore strictly differentiates between lamps for open and closed luminaires Lamps for open lu minaires have a mechanical safeguard around the arc tube to ensure that all fragments remain intact within the outer bulb should the arc tube burst Compliance with this requirement is ensured through inhouse tests at OSRAM which are much more stringent than in actual operation and in some published standards for example ANSI Standards This is the corresponding pictogram for lamps of this kind as per IEC 62035 As it is generally not possible to rule out the pos sibility of the lamp bursting for all other lamps metal halide lamps must be operated in closed luminaires which are designed to contain all hot fragments of the lamp in the case of it bursting The corresponding pictogram for lamp and luminaire according to IEC 62035 is shown on the right Silicate glass panes are recommended as a cover scr
91. ratio at 220 V 140 150 160 170 180 190 200 210 220 230 240 250 260 Supply voltage US in V Fig 25 Relative change in the re ignition peak Us to supply voltage U referred to the ratio at 220 V for various metal halide lamps 23 24 re ignition voltage and the current supply voltage de creases If the re ignition voltage exceeds the supply voltage the lamp goes out see also chapter 6 2 2 Increase in re ignition peak This means that POWERBALL HCI must not be dimmed by reducing the supply voltage as the re ignition peak can cause earlier extinguishing of the lamp or flicker 5 2 2 Phase control leading edge trailing edge Fig 26 and 27 show the decrease in effective supply voltage by phase control with leading edge or trailing edge There are also variations in which the supply voltage is reduced in the middle and not before or after the zero crossing In other versions the supply voltage in the leading edge phase is only decreased and not reduced to zero U Supply voltage U Lamp voltage a Ignition angle Current flow angle Fig 26 Principle of phase control with leading edge idealized diagram U Supply voltage U Lamp voltage a Ignition angle Current flow angle Fig 27 Principle of phase control with trailing edge idealized diagram For the phase control with leading edge the result ing intervals with no current result in a greater cooling down of plasma end electrodes
92. ration Ltd in Techni cal Statement No 30 and by the ZVEI in the Lamp manufacturers statement regarding EN 62035 certain lamps do not require any safety measures to prevent asymmetrical conductivity As far as OSRAM s metal halide lamps are concerned this refers to lamps with wattage levels of 1000 W and more Although asymmetrical conductivity is generally pos sible in lamps with wattages gt 1000 W both during the start and in steady state the dimensions of the arc tube and lamp components means that the tendency to asymmetrical conductivity is far less than with smaller wattage levels and is weak enough in steady state that no safety measures against asymmetrical conductivity are required OSRAM PTi is not affected by asymmetrical conduc tivity as Current and voltage are monitored and con trolled which is why it is recommended for the opera tion of discharge lamps 6 3 10 Conclusions e Safe operation of metal halide lamps depends on the use of luminaire parts lamp holder leads etc which can withstand the high temperatures that can possibly occur in the case of outer bulb discharge Apart from burst protected lamps for operation in open luminaires all lamps must be operated in closed luminaires All metal halide lamps with small wattage must be equipped with a safeguard to protect the lamp from the effects of asymmetrical conduc tivity e g chokes with thermal protection It is advisable to use ig
93. rces CRI 95 Larger deviations are associated with a clear tint The distance to Planck is also known as the chromaticity gap Ac Colour rendering is specified by irradiating defined test colours in succession with a reference source an ideal Planck radiator with the temperature and therefore co lour temperature of the test light source and with the test light source The specific resultant colour shift AE is defined for every test colour i in the uniform colour space CIE 1964 W U V The specific colour rendering index R is defined as follows R 100 4 6 Ae Every special colour rendering index can therefore reach a maximum value of 100 when the test colour appears identical under reference and test light source Negative values are also possible with greater deviations and hence larger AE 8 2 1 Test colours from standard DIN 6169 The arithmetic mean from the first 8 test colours see Table 4 shows the general colour rendering index CRI or R The general colour rendering index results in the colour rendering levels for light sources given in Table 5 Table 4 Test colours from DIN 6169 R1 Dusky pink wu R2 Mustard yellow El R3 Yellow green ia R4 Light green R5 Turquoise blue R6 Sky blue ES R7 Aster violet R8 Syringa violet J Saturated colours and additional test colours R9 Red m R10 Yellow Ei R11 Green si R12 Blue FE
94. rtain lamp wattage Either conven tional chokes or electronic ballasts can be used To change the nominal lamp wattage of a lamp the following general physical conditions are significant for the resulting effects e The electrodes of discharge lamps are rated for a certain lamp current If the current is too high parts of the electrodes melt and evaporate If the current is too low the electrode is operated in cold state This changes the mechanisms for releasing electrons from the electrode with more electrode material being deposited on the tube wall Deviations in lamp current from the nomi nal value in both directions can therefore cause blackening of the arc tube wall with a decline in luminous flux together with negative effects on the light colour and possibly also on the ser vice life The partial vapor pressure of the filling particles responsible for generating light depends on the temperature of the arc tube wall A change in the arc tube wall temperature resulting from a change in lamp wattage influences the composi tion of the filling in the plasma arc and thus the electrical and photometric properties of the lamp At higher arc tube wall temperatures the metals do not recombine with the iodides and the pure metals can migrate into the wall applies to quartz arc tubes Wattage reduction has the following side effects e Drop in luminous flux through blackening of thearc tube e Change in color properties e R
95. s Hal Halids 700 nm Alternative ECG supply voltage Fig 2 Tasks of the metals sodium Na thallium TI indium In tin Sn lithium Li rare earths dysprosium Dy holmium Ho thulium Tm Dy Ho Tm Sn SS 6 10 e 1 pe gt 7 Yellow gt na Variation possibilities of the Colour Temperature Tn CRI gt 5000K gt 90 ca 4000 K 60 69 4200K 280 3000 K gt 70 Daylight D Neutral White N Neutral White de luxe NDL Warm White deluxe WDL Fig 2a Generation of the desired Spectral Distribution Components in order to achieve high luminous Effica cies and good Colour Rendering 2 1 Quartz discharge tube The discharge tubes in 1st generation metal halide lamps are made of high purity quartz glass This quartz material allows for stable operation at high tempera tures is resistant to sudden changes in temperature and is transparent The well proven HQI lamps are pro duced in various different forms using this technology H ate Hydrargyrum Greek Latin for mercury Q Quartz er lodide Well proven lamp technology Wide wattage range 70 W 2000 W Colour temperatures up to 7250 K Good optical properties thanks to transparent discharge tube 2 2 Ceramic discharge tube PCA polycrystalline alumina The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp s properties Ceramic can withstand higher temperatures than quartz glass This
96. s for tubular fluorescent lamps 61347 2 5 Lamp control gear Part 2 5 Performance requirements Particular requirements for d c supplied electronic ballasts for public transport lighting Accessories Safety E Lamp control gear Part 2 6 Particular requirements for d c supplied electronic ballasts for aircraft lighting 61347 2 6 61347 2 9 Lamp control gear Part 2 9 Particular requirements for ballasts for discharge lamps excluding fluorescent lamps 61347 2 12 Lamp control gear Part 2 12 Particular requirements for d c and a c supplied electronic ballasts for discharge lamps excluding fluores cent lamps Luminaires 60598 1 IEC CISPR15 and similar equipment IEC 61547 IEC 61000 3 2 Performance Auxiliaries for lamps Ballasts for discharge lamps excluding tubular fluorescent lamps Performance requirements Luminaires Part 1 General requirements and tests Limits and methods of measurement of radio disturbance characteristics of electrical lighting Equipment for general lighting purposes EMC immunity requirements Electromagnetic compatibility EMC Part 3 2 Limits Limits for harmonic current emissions equipment input current lt 16 A per phase Not all lamps are covered by data sheet in the lamp standards but the application range of every standard applies to all lamps of the corresponding type Vibration and impact tests are covered by IEC 60068 2
97. specifies limit values in the respective lamp data sheets This means that the UV radiation of the lamp in the range 250 400 nm is weighted with a so called evaluation function see figure 55 similar V A evaluation of visible radiation This evaluation curve shows the generalized sensitivity of human tissue to UV radiation over wavelength and has been defined by the ICNIRP International Com mission on Non lonizing Radiation Protection This evaluation curve is used today by nearly all na tional and international bodies standardization pro fessional associations etc The ACGIH American Conference of Governmental Industrial Hygienists uses this evaluation for workplace guidelines The NIOSH National Institute for Occupational Health and Safety is an American federal authority that re searches occupational health and safety and issues corresponding recommendations The maximum daily dose 8h working day permitted according to the ICNIRP is 30 J m With a mean illu minance of 500 Ix this dose is achieved with an effec tive UV radiation of approx 2 mW klm The IEC 61167 data sheets for metal halide lamps indicate the maxi mum values of the generated effective UV radiation IEC 62035 states the limit values for UV radiation 2 mW klm resp 6 mW klm for high intensity discharge lamps as an indication for the luminaire manufacturer 51 52 OSRAM metal halide lamps comply with the limit values of 2 mW klm or e
98. st be given to the voltage drop in the outgoing and incoming cable e 230 V systems are more sensitive to additional line resistance than 400 V systems In applications demanding the lowest possible colour scattering the supply conditions should be approxi mately the same i e supply voltage or line resistance should be equivalent 7 5 Maintenance of lighting systems with metal halide lamps Since March 2003 the EN 12464 1 standard applies to interior lighting systems throughout Europe If a lighting system is being planned according to this standard it is necessary to draw up a maintenance plan This has to take into account influences causing a drop in luminous flux in the system during the course of the service life such as dirt depreciation of lumi naires and the room itself together with the aging of the lamps and lamp failures The maintenance factor replaces the previous planning value Maintenance factor MF LLMF x LSF x LMF x RMF LLMF lamp luminous flux maintenance factor LSF lamp survival factor LMF luminaire maintenance factor RMF room maintenance factor 3 38 Example for a maintenance plan Maintenance plan Only regular maintenance can ensure compliance with the stipulated illuminance levels in the EN 12464 standard for the lighting system The following maintenance intervals must therefore be followed Room Type of surrounding Maintenance interval Luminaire XXX Influence of reflect
99. technology is also apparent for the other colour rendering indices 8 3 Light and quality of life It has been a known fact for many years that as well as its known visual effects light also has other biological effects on the human body The most acknowledged effect is the way light influences the day and night cycle This influence is also perceived by the eyes not however via the vision center in the brain but via other nerve cells that affect the pineal gland and hence the forming of the sleep hormone melatonin Bright light in the night suppresses the formation of melatonin Pineal gland Visual center pineal gland a release of melatonin Ganglion cell in upper cervical vertebra Spinal cord Fig 53 How light affects on the human brain reducing the level of melatonin in the bloodstream This is called melatonin suppression see Fig 53 Scientific studies on how light forms or suppresses the sleeping hormone melatonin have shown that together with the visual path which is responsible for vision there is also a non visual path which independent of the visual system controls melatonin production and therefore the circadian rhythm daylight rhythm While the visual path leads directly from the eye to the vision center of the brain via the optic nerve the non visual path is coupled via the suprachiasmatic nucleus SCN to the pineal gland and controls melatonin pro duction This process is relatively slo
100. then to cracks and lamp failures A fur ther sensitive component is the lamp s getter Sealing area Capillaries Figure 40 Example of a reflector with a reflector neck over the thermally critical parts of the lamp To establish whether or not the luminaire design could Cause impermissible thermal damage the temperature on the outer bulb and the socket or the pinch area first need to be measured as stated in the catalogues see also section 7 1 However it should be noted that even if the tempera tures measured on the outside of the lamp lie within the defined tolerance values this does not necessarily mean that there is no overheating inside the lamp Those surfaces closely surrounding the lamp such as the reflector neck diffuser tube and glare shield caps reflect back on the lamp Likewise elliptical reflectors radiate back onto the lamp if the burner is not posi tioned correctly in the burner point of the reflector In these cases the lamps may also suffer damage even if the temperatures measured on the outside of the lamp lie within the defined tolerance values The following recommendations are made To avoid glare the glare shield caps often used for halogen bulbs or the glare shield rings on lamps with double sided burners such as HCI may not be used Instead the glare protection for these lamps is effected by using e g honeycomb filters or anti glare baffles or hoods attached to the outside
101. ther safety devices e failure or malfunction of computers drivers lighting installations and other sensitive consumers e thermal overload of transformers caused by increased iron losses e overload of the neutral conductor particularly by the 3 harmonic wave e shattering or bursting of discharge lamps e thermal overload of the lamp choke due to reso nance between choke and capacitor for power factor correction The effects can be similar to asymmetrical mode see chapter 6 2 9 which is why the use of a choke with thermal protection can also protect the luminaire from burning The installation of so called choked capacitors ca pacitor in series with a filter choke aims at forcing the resonance frequency of the grid below the frequency of the lowest prevailing harmonic wave This prevents a resonance between the capacitors and the grid and would thus also prevent the amplification of the har monic currents This kind of installation also has a fil tering effect by reducing the level of voltage distortion in the grid It is therefore recommended for all cases where the wattage share of the loads that generate harmonic waves is more than 20 of the total watt age The resonance frequency of a choked capacitor always lies below the frequency of the 5 harmonic wave In the electronic ballast OSRAM POWERTRONIC PTi the influence of harmonic waves on the lamp is kept extensively at bay by the ballast design which com prises an inter
102. tor of 0 68 for example for 9000 h Given the lesser drop in luminous flux in POWERBALL HCI over the service life compared to standard metal halide lamps with cylindrical tube the maintenance factor for 9000 h is 0 8 In practice this results in the following application cases see also table 2 To achieve a constant luminous flux of min 500 Ix throughout the service life taking cleaning and change intervals into account the following applies initially e Standard lamp and lamp change after 3 years i e for an LLMF of 0 68 case 1 962 Ix approx 17 higher illuminance i e more luminaires e POWERBALL HCI and lamp change after 3 years i e for an LLMF of 0 8 case 2 820 Ix e Standard lamp and lamp change for an LLMF of 0 8 here after 14 months case 3 820 Ix lamp change required after 14 months as 80 of the initial lumens achieved after 3500 h Table 2 Comparison of change intervals for different lamp types Lamp Maintenance intervall 1 Year 2 Months W 830 PB Operating hours year 3000 3000 3000 Immediate exchange of defect lamp LLMF according CIE POWERBALL HCI according CIE Diagrams showing luminous flux behaviour and survival rate can be found in the Technical Data of the lamps in the online catalogue 7 6 Standards and directives for discharge lamps 7 6 1 Standards The international body for issuing standards relating to The standards for lamps and accessories are broken el
103. tween socket and lamp holder and at the electrical contact the temperatures are naturally much lower Here in extreme cases 300 C were measured at the contact between lamp Arc discharge Incandescent lamp mode and lamp holder and 250 C at the electrical contact of the lamp pin to the lamp holder The electrical contact is also relevant for the Temperature Code of the socket See also chapter 7 3 lamp holder If metallic coatings in the pinching area form through material deposition from the leads so that they form a continuous conductive layer between the leads then the result in the so called incandescent mode The metal coating offers sufficient resistance that power is consumed and the coating begins to glow It is hereby possible that electrical values similar to normal opera tion are reached which would make it impossible for an electronic ballast for example to detect this abnor mal situation This also causes high temperatures in the pinching area Glow and arc discharges can be detected by current and voltage values deviating from the normal levels so that an electronic ballast with a corresponding automatic cut out feature can switch off such lamps In addition the luminaire design must use components resilient to high thermal loads so that the possibly high tempera tures will not lead to harmful situations for the operator 6 3 2 Increase in re ignition peak The re ignition peak is a peak in the lamp voltage
104. uilding illumination facilities High luminous flux permits few fixtures light points Long service life with longer change intervals High efficacy and long service life Good colour rendering High luminous flux permits few fixtures light points Small dimensions permit compact luminaires Small arc tubes permit very good light control The means of generating light is technically com These application instructions address a large number plicated The key principles regarding the opera of users such as luminaire designers lighting planning tion of these lamps and instructions for their use engineers operating device developers and retailers are listed below Naturally not all users will find all sections relevant but the aim has been to cover the interests of as many users as possible 2 How a metal halide lamp works Similar to high pressure mercury lamps or high pres sure sodium lamps metal halide lamps also belong to the group of discharge lamps Low pressure discharge lamps include fluorescent lamps and compact fluores cent lamps In discharge lamps light is generated by a gas dis charge of particles created between two hermetically sealed electrodes in an arc tube After ignition the particles in the arc are partially ionized making them electrically conductive and a plasma is created In high intensity discharge lamps the arc tube is usually enclosed in an evacuated outer bulb which isolates
105. umes that the lamp is defective or not inserted The selected timer period must be sufficient to allow the lamp enough time to cool down following a power interruption so that lamp re ignition is again possible The warm re ignition times of the POWERBALL are under 10 minutes far shorter than those of the cylindrical version 4 3 Hot re ignition High ignition voltages of 16 to 60 kV are necessary for immediate re ignition of hot metal halide lamps hot re ignition on account of the high vapor pressures The lamp sockets and luminaire must be designed for these high voltages and suitable ignition units must be used There are two versions of hot re ignition units with symmetrical and asymmetrical ignition pulses In the asymmetrical units care must be paid to correct polarity of the lamp connections At present hot re ignition is permitted for double ended quartz lamps with a few exceptions As far as ceramic lamps are concerned the single ended HCI TM series with GY22 socket are approved for hot re ignition Approval of other double ended ce ramic lamps is in preparation 4 4 Ignition at low ignition voltage Penning effect Various methods can be used to reduce the voltage necessary to ignite the lamp One such method uses the so called Penning effect When the energy stored in a meta stable excitation level of the basic gas is larger than the ionization energy of the admixture vol ume ionization begins at lower
106. ut in addition there are also considerable differences between operation on an electronic or magnetic ballast The following section briefly explains the main differ ences and their effects 3 2 1 Structure and functioning of an electronic ballast Electronic ballasts mainly consist of units with rect angular current and voltage In principle it is also possible to operate the lamps with high frequency sinusoidal current similar to the fluorescent lamp In any case it is important to ensure that no acoustic resonances occur as these may result in arc instability lamp flicker and in severe cases lamp rupture 3 2 2 Service life and temperature There is a significant difference between conventional and electronic ballasts particularly with regard to the service life and thermal behavior of the units Luminaire Fig 13 Simplified circuit diagram showing the elec tronic operation of high intensity discharge lamps Voltage in V 200 160 120 80 40 0 40 80 120 4 0 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Time in ms Fig 14 Current and voltage of a metal halide lamp operated on a rectangular electronic ballast For a conventional ballast it can be presumed that the service life is defined by the choke temperature t A 10 C increase in the t temperature means that the servi
107. ven go below the limit considerably Exceptions are the HQI lamps without outer bulb with the power of 1000 W and 2000 W Here special safety precautions have to be met by the luminaire Standardization of UV variables per klm or Im of fers the advantage of being able to make direct com parison of the relative radiation shares of various lamp types and wattage classes with regard to the same application illuminances As a comparison e Tubular Fluorescent T8 amp T5 have an ACGIH UV value of approx 0 2 mW klm with possible minor fluctuations depending on wattage class and light colour e Compact lamps have a lower 0 03 mW klm oO 00 oS D rel UV hazard 0 4 Kad N Fig 55 Evaluation function for the sensitivity of human tissue to UV radiation as per ICNIRP 8 4 1 Fading effect The colour change in light sensitive materials resulting from irradiation with light sources depends on e irradiance or illuminance e spectral distribution of the radiation from the light source e spectral object sensitivity effect function and e irradiation time If daylight contributes to the lighting e g via skylights or shop windows this has to be considered as part of the irradiation as well Daylight contains considerable amounts of light in the UV range und short wave vis ible light In new objects colour change is strongest during the initia
108. verheating capillaries with the effects described above In rare cases a dis charge attachment near the arc tube wall in ceramic lamps can cause the arc tube to burst A broken electrode in a lamp with quartz arc tube can after a longer period of time cause the arc tube wall to bulge and possibly leak or burst if the discharge still persists 6 3 7 Scaling of the base socket Particularly in the case of old ignition units without automatic cut out and aged lamps or soiled contacts high transition resistances can cause oxidation and thus overheating of the contacts When ignition pulses persist for a longer period of time if lamps have gone out because the re ignition peak is too high or if the lamp has not ignited it is possible for arc over to oc cur in the socket If scaling has occurred the socket must be replaced as well as the lamp Vibrations can cause the lamp to become loose with the possibility of arc overs and scaling caused by the resulting poor contact In these cases the usage of a lamp holder with retention device is recommended as described in the standard IEC 60238 Edison screw holders section 2 23 Lamp holder with retention de vice The test conditions are described in section 12 14 Suspending the luminaire on a chain attenuates vibrations compared to suspending it on a rope 6 3 8 Bursting of the lamp It is generally possible for the arc tubes of metal halide lamps to burst This is very
109. w in time con stants of several minutes while the process of vision takes place within a few 10 ms The SCN is a collection of several thousand nerve cells located above the intersection of the optic nerves chiasma This is deemed today to be the main regulator of the inner clock master clock Suprachiasmatic Nucleus SCN Retino hypothalamic tract RHT And so we distinguish between the visual path re sponsible for all visual tasks such as recognizing pic tures perceiving brightness contrast shapes etc and the non visual path or also biological path which controls in particular the circadian rhythms and also influences in the daytime our alertness and men tal performance and also biological functions such as hormone production the blood circulation and the metabolism The non visual path is essentially independent of the visual path Non visual path Visual path e Cirkadian rhythm Alertness Tiredness e Hormone production Vitality e Recovery Blood circulation e Metabolism e Recognizing pictures Brightness illuminance e Contrast e Shapes e Movement e Perception Information Scientific studies Prof Brainard Thomas Jefferson University Philadelphia have established that mela tonin suppression depends not only on brightness but also on the wavelength of the light used Light in the blue spectral range of about 460 nm has the strongest effect on suppressing m
110. wattage when using an inductive ballast can also be achieved by varying the frequency of the power supply as the inductive resistance of the choke depends on frequency The change in choke imped ance at low frequencies has been dealt with in the preceding chapter 5 2 3 If the change in impedance is caused by changing the frequency in radiofrequency operation in discharge lamps the possible occurrence of acoustic resonances has to be considered Resonance in the discharge tube can cause the plasma to start to oscillate de pending on the arc tube geometry and plasma tem perature This can cause the lamp to flicker or go off and in extreme cases destruction of the lamp should the arc attach to the arc tube wall due to severe reso nance This is why a currently proposed standard for electronic operation of metal halide lamps limits the amount of high frequency oscillations It is difficult to find reliably resonance free operat ing windows for various reasons the resonance frequencies change during the start up and also dur ing the course of the service life Lamps of differing geometries and filling also show different resonance frequencies A reduction in wattage also changes the resonance frequencies due to the change in plasma temperature 5 3 Recommendations for reducing the wattage in discharge lamps 5 3 1 Metal halide lamps Operation of OSRAM POWERSTAR HCI cylindri cal burner and OSRAM HQI lamps with reduced

Osram HQI-E 150 W/NDL CL

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