Difference between revisions of "Philips HPI Plus"

Standard Metal Hallide Lamp for indoor and outdoor lighting with 250W and 400W (E40 base), coated bulb

*Diffuse internal elliptical coated bulb

*E40 base

*Luminous efficacy of 72 to 82 lumens/watt

*Vertical or horizontal operating position

*Requires external gear (similar to mercury vapour lamps) and appropriate wiring:

** Philips BHL or compatible reactive inductive ballast with matching power rating

 

[[Image:Philips HPL-N 250W.jpg|Philips HPI Plus 250W]]

! Designation !! Base !! Lamp wattage !! Luminous flux !! Colour appearance !! Colour Temperature !! Colour Rendering Index (Ra8) !! Life (to 50% failures)

| MASTER HPI Plus 250W/767 BU E40 CRP/SLV || E40 || 250 W || 18000 lm || Daylight || 6700 K || 69 || 20000 hours

| MASTER HPI Plus 250W/767 BU-P E40 CRP/SLV || E40 || 250 W || 18000 lm || Daylight || 6700 K || 69 || 20000 hours

| MASTER HPI Plus 400W/745 BUS E40 CRP/SLV || E40 || 400 W || 30000 lm || Cool White || 4500 K || 69 || 20000 hours

| MASTER HPI Plus 400W/745 BUS-P E40 CRP || E40 || 400 W || 30000 lm || Cool White || 4500 K || 69 || 20000 hours

* "S" designation indicates lamps with integrated internal starter that do not require an external ignitor;

* "P" means protected lamp, suitable for open air use;  

* "BU" means base up operation while "HOR" means horizontal operating position.

| High light output in very compact package || No lower wattage lamps available

| High efficiency, long life, average colour rendering || Quite expensive lamps

| Mostly omni-directional light || Sensitive to operating position and unbalanced wearing

| Reduced lamp glare, quick lamp start || Slow restart, requires bulky, heavy, complex lamp gear

HPI Plus lamps are the best choice since they do not require specific fixtures for operation, their ovoid outer bulb allowing simple operation and less glare with possible operation as free standing, hanging, lamps. HPI-T lamps are much more effective for flood lighting but they require specific fixtures and have higher surface temperature, making them more susceptible to damage when improperly handled. Chinese branded lamps are much worse in all performance and quality metrics with shorter useful life, worse colour reproduction and and efficiency as a proper, stable mix of hallides required huge research investment that was too costly for Chinese producers.

The best choice are, probably, the 250 watt lamps as larger powered lamps are too powerful for most purposes. This lamp wattage was also cheaper as they were highly popular. Electro-magnetic ballasts or conventional gears are plentiful and can be used interchangeably with all manufactured lamps for a specific wattage and ignitors' performance is less critical as on high pressure sodium lamps. Lower rated power output gears can be used, but it is not recommended as colour reproduction and lamp lifetime will be reduced while higher powered ones damage the lamp due to over-stressing and is highly dangerous.

Used lamp gears might work but old lamps are never desirable as they degrade much quicker than mercury vapour and sodium lamps. Rusted ballast may still operate but are a potential hazard while old, used lamps, may not have much useful life left and they may already exhibit some colour light emission issues. New old-stock lamps are the best choice, if available.

The lamp technology was an improvement of previously developed mercury vapour lamps. The potential for fluorescent powders was mostly exhausted by early 70s which meant that research concentrated on releasing better lamps that produced light directly from the discharge tube. This research was also carried previously but results were modest, as stable compounds with good colour reproduction were found to be quite aggressive and lead to short service life. Sodium, Scandium, Indium, Thallium were attempted as main elements that can offer a balanced light output but they required a specific balance of temperature and pressure to achieve best results. One major limitation was that certain compounds were costly or difficult to manufacture or mix in specific amounts, which meant that suitable results could not be found for many decades. In the late 70s and early 80s most major manufactures were able to center on specific technologies that reached good enough results for general lighting, with predictable performance.

The market for large lamps was important as there was an interest in using more energy efficient lamps when the early 1970s oil crises brought new challenges. High pressure mercury vapour lamps were efficient but their light was not white while improvements in high pressure mercury vapour lamps were not satisfactory. While metal hallide lamps were more expensive than mercury vapour lamps, the energy savings that were around 25 to 50% meant that this technology was attractive enough considering much improved colour reproduction despite shorter lifetime. The ability to run on mercury vapour gear and the ability to retrofit these fixtures was critical to market success while the ability to run on high pressure sodium lamps ensured improvements on other installations. These are the most important factors that ensured market success as metal hallide lamps required careful installation, operation and restocking.

Of course, metal hallide lamps were always less successful than fluorescent lamps, especially when larger fixtures, especially indoors, were not an issue. Fluorescent lamps were easy to stock, replace, had a longer useful life and they offered custom light reproduction with great prospects for energy efficiency improvements. Lower power rating metal hallides were developed and marketed but they required specific fixtures that were able to withstand the possibility of a blown old arc tube and the high heat output and complex operating gear, along with worse flicker than fluorescent lamps. All this, along with a large price justified by complex manufacturing quality control, meant that fluorescent lamps were always more popular in most commercial and all residential applications.

LED lamps affected the most this expensive lamp and gear technology, as it quickly surpassed it in ease of use, much longer useful lifetimes, better colour reproduction and versatility in both indoor and outdoor applications. This means that the market for metal hallide lamps was quickly diminishing even quicker than high pressure sodium vapour or even the older mercury vapour lamps, both surviving longer due to lower lamp replacement costs.

Most manufacturers have been releasing lamps for many decades and constantly improved technology so that lamps had a stabler, predictable lifetime and slightly improved colour stability due to manufacturing progress. Lamps produced in the 70s and early 80s are probably not commonly found today. In the 90s and early 2000 Philips was manufacturing lamps in Holland and other countries, while in the last years they were doing the same thing in China. Quality was not severely affected as manufacturing quality was maintained and applications were demanding, used in wealthier countries. It should be noted that there are larger differences between compatible lamps released by Osram, General Electric or other major manufacturers as each of them settled on slightly different chemistry with different reliability and performance.

Products manufactured by Philips were similar to General Electric and Osram, with a quality and consistency much above some East-European manufacturers in terms of colour rendering, light output and life. However, Philips was manufacturing lamps with shorter lifetimes and poorer colour reproduction than typical Osram ones, especially on standard metal hallide lamps, as Philips was focusing on cost and marketing. On the other side, Philips lamps were much more popular and are easier to find.