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== Review == | == Review == | ||
These high pressure mercury vapour lamps are compact light sources that are viable for wide area lighting. Their average colour reproduction and large output means that they are better suited to outdoor lighting. Compared with flourescent lamps they were very compact, having better performance at low temperatures. A longer lifetime, that was around 10 to 15 times higher than tungsten lamps, meant that these lamps are well suited for use in places where lamp replacement was costly, as in high bay lighting and street lighting. They had similar useful life as fluorescent lamps. High pressure sodium lamps had higher light output, almost double, of mercury vapour lamps while having low quality colour reproduction. This means that mercury vapour lamps were still suited for areas where colour reproduction was moderately important and there was still an advantage from compact light sources, which means industrial and workshop lighting, sometime even commercial premises. | These high pressure mercury vapour lamps are compact light sources that are viable for wide area lighting. Their average colour reproduction and large output means that they are better suited to outdoor lighting. Compared with flourescent lamps they were very compact, having better performance at low temperatures. A longer lifetime, that was around 10 to 15 times higher than tungsten lamps, meant that these lamps are well suited for use in places where lamp replacement was costly, as in high bay lighting and street lighting. They had similar useful life as fluorescent lamps. High pressure sodium lamps had higher light output, almost double, of mercury vapour lamps while having low quality colour reproduction. This means that mercury vapour lamps were still suited for areas where colour reproduction was moderately important and there was still an advantage from compact light sources, which means industrial and workshop lighting, sometime even commercial premises. | ||
While it is true that lamps have an inherent flicker due to mains operation and slight changes in light output due to operation in this circumstances with mains powered conventional gear, this effect is not as pronounced. Note that also flourescent lamps that use electro-magnetic gear exhibit the same issues, although they are less pronounced as the lamp is not operating at higher pressure and being more susceptible to a certain voltage uniformity. There was no electronic high frequency gear as used on fluorescent lamps or metal hallide lamps, even if, they could be adapted. Of course, the biggest issue is that the lamp can be damaged if attempts to operate with this gear are underway such as melting of internal components when the lamp does not strike, after a sudden interruption, and a discharge occurs in the outer bulb with no way to stop it automatically. | |||
Fixtures are generally compact, considering the light output made available, but are generally heavy due to the bulky electromagnetic gear being used. There are directional and omni-directional fixtures that are suited to various purposes. In street lighting, the well known cobra-head style lamppost was used, and they may still be available for purchase. They were only moderately effective as light covered a large area but a considerable amount of light was lost due to the fixture directing some of it upwards, with no control. Omni-directional fixtures were used in residential areas and parks, where ambience was more important than efficiency. Indoor fixtures were centered on the typical high-bay or low-bay purposes, having a metal parabolic reflector and directing most or the entire light output downwards. Other fixtures were compact, having a boxy design, with a symmetrical or asymmetrical lamp placement that was suited for flood lighting. These type of lamps were used indoor as well as outdoor, for floodlighting. There were no home designed fixtures as these lamps were not popular in home environments and were mostly used as porch lighting with a fixture design similar to street or area lighting. | Fixtures are generally compact, considering the light output made available, but are generally heavy due to the bulky electromagnetic gear being used. There are directional and omni-directional fixtures that are suited to various purposes. In street lighting, the well known cobra-head style lamppost was used, and they may still be available for purchase. They were only moderately effective as light covered a large area but a considerable amount of light was lost due to the fixture directing some of it upwards, with no control. Omni-directional fixtures were used in residential areas and parks, where ambience was more important than efficiency. Indoor fixtures were centered on the typical high-bay or low-bay purposes, having a metal parabolic reflector and directing most or the entire light output downwards. Other fixtures were compact, having a boxy design, with a symmetrical or asymmetrical lamp placement that was suited for flood lighting. These type of lamps were used indoor as well as outdoor, for floodlighting. There were no home designed fixtures as these lamps were not popular in home environments and were mostly used as porch lighting with a fixture design similar to street or area lighting. | ||
Nowadays, mercury vapour lamps are very well suited for outdoor lighting. As the number of available fixtures diminishes and only second-hand or used products are available, they may not be economically effective to purchase except when you can readily use them rather than collect them. Free standing lamps are quite capable on their own so if you need a compact light source that is highly durable and colour output is appreciated as is, then high pressure mercury vapour lamps are well suited. They are especially well suited for lighting in areas that are undergoing renewal work, workshops, gardens. Of special interest is renewals, since no modern LED lamp can output the same light spectra that dulls old painted areas and brightens newly painted ones. | Nowadays, mercury vapour lamps are still very well suited for outdoor lighting. As the number of available fixtures diminishes and only second-hand or used products are available, they may not be economically effective to purchase except when you can readily use them rather than collect them. Free standing lamps are quite capable on their own so if you need a compact light source that is highly durable and colour output is appreciated as is, then high pressure mercury vapour lamps are well suited. They are especially well suited for lighting in areas that are undergoing renewal work, workshops, gardens. Of special interest is renewals, since no modern LED lamp can output the same light spectra that dulls old painted areas and brightens newly painted ones. | ||
== Operation == | == Operation == | ||