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Difference between revisions of "Philips ML"
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*Yttrium Vanadate internal coated bulb | *Yttrium Vanadate internal coated bulb | ||
*High pressure mercury vapour lamp with an internal quartz discharge tube | *High pressure mercury vapour lamp with an internal quartz discharge tube | ||
*E27 base or E40 base | *Integrated internal ballast featuring an incandescent coil (filament) | ||
*E27 base or E40 base | |||
*Soft glass (100, 160 and 250W) or Hard glass (250 and 500W) | *Soft glass (100, 160 and 250W) or Hard glass (250 and 500W) | ||
*230V operating voltage (highly sensitive to voltage) | *230V operating voltage (highly sensitive to voltage) | ||
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Generally, mercury vapour lamps were very durable but mixed lights, mercury vapour and tungsten, are quite sensitive. Strong, sudden shocks can damage the internal tungsten filament, permanently affecting the lamp. On each start-up the lamp is highly stressed as the tungsten filament operates at almost double the normal rated current which means that service life is strongly affected by switch on frequency. The lamp is impossible to service if any rupture of the filament occurs. | Generally, mercury vapour lamps were very durable but mixed lights, mercury vapour and tungsten, are quite sensitive. Strong, sudden shocks can damage the internal tungsten filament, permanently affecting the lamp. On each start-up the lamp is highly stressed as the tungsten filament operates at almost double the normal rated current which means that service life is strongly affected by switch on frequency. The lamp is impossible to service if any rupture of the filament occurs. | ||
All the above particular operating issues make the lamp slightly inconvenient to operate, even if the lamp itself is highly attractive to use and install and not an expensive purchase. | All the above particular operating issues make the lamp slightly inconvenient to operate, even if the lamp itself is highly attractive to use and install and not an expensive purchase. Failing lamps can be easily determined by the lengthened time of restart in case of power being cut off and then resumed. A longer than typical time and less definite starting after cooldown, meaning more failed attempts at restarting than 1 or 2, point to a worn of lamp that will soon be dead. Of course, as mentioned before, this should be tested with the same straight vertical position. However, as lamps age, they will be more sensitive to voltage, accumulated heat nearby the lamp than newer ones so actual service life can be severely reduced compared with what the datasheet may suggest. | ||
== Greatest features & flaws == | == Greatest features & flaws == | ||
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The only slight drawbacks are the lamp's sensitivity to positioning and operating voltage, along with slightly lower than average service life, especially compared with modern lighting technology. The lamp's low efficiency is caused by the compromise of its internal construction. The warm light generated by the internal filament also comes with massive heat radiation, which is similar to typical tungsten lamps that were previously popular. | The only slight drawbacks are the lamp's sensitivity to positioning and operating voltage, along with slightly lower than average service life, especially compared with modern lighting technology. The lamp's low efficiency is caused by the compromise of its internal construction. The warm light generated by the internal filament also comes with massive heat radiation, which is similar to typical tungsten lamps that were previously popular. | ||
The pleasant light is suited both as general lighting in homes as well as gardens or workshops. A good selection of lamps can be used if power consumption is not critical and a specific scene or effect is desirable. Unfortunately, especially in small spaces, the lamp can contribute to heating, which may be advantageous as well as undesirable, depending on application. Special care should be taken when cleaning the lamp as vibrations, dirt accumulation and improper handling can easily crack the bulb, especially on soft glass lamps. Any dirt present on the lamp may be trapped longer due to melting and subsequent adhesion to glass. This means that lamp cleaning has to be as thorough and careful as on old tungsten lamps. | The pleasant light is suited both as general lighting in homes as well as gardens or workshops. A good selection of lamps can be used if power consumption is not critical and a specific scene or effect is desirable. Unfortunately, especially in small spaces, the lamp can contribute to heating, which may be advantageous as well as undesirable, depending on application. Special care should be taken when cleaning the lamp as vibrations, dirt accumulation and improper handling can easily crack the bulb, especially on soft glass lamps. Any dirt present on the lamp may be trapped longer due to melting and subsequent adhesion to glass. This means that lamp cleaning has to be as thorough and careful as on old tungsten lamps. While the lamp has a very high output when started and slowly reduces on warm-up, with a corresponding change in light colour, it is not unpleasant. At the beginning most light is output by the internal incandescent fillament rather than the mercury discharge. Lamp restart in case of failure occurs in less than 2 minutes and is less unpleasant than on other high pressure discharge lamps. | ||
This type of mercury vapour lamps were popular mostly before the oil crisis that occured in the 1970s. Many years have passed since use of this lamp was basically non existant, meaning that stocks are not very large. Although the lamp could directly replace even less efficient tungsten or incandescent lamps, this market very rapidly diminished as soon as compact flourescent lamps with screw bases were made available. These had a much longer life, had no restriction on mounting, were highly energy efficient and had even better colour reproduction. There were few fixtures specifically designed for Philips ML lamps. They could operate on typical high pressure mercury vapour fixture but this was uncommon. There was a market for street-lighting in France, many decades ago, as the lamp offered a pleasant light and energy was quite cheap. Due to the lamp operating restrictions as well as simple use, free standing or hanging mounting were quite common, even if lighting efficiency was diminished. | This type of mercury vapour lamps were popular mostly before the oil crisis that occured in the 1970s. Many years have passed since use of this lamp was basically non existant, meaning that stocks are not very large. Although the lamp could directly replace even less efficient tungsten or incandescent lamps, this market very rapidly diminished as soon as compact flourescent lamps with screw bases were made available. These had a much longer life, had no restriction on mounting, were highly energy efficient and had even better colour reproduction. There were few fixtures specifically designed for Philips ML lamps. They could operate on typical high pressure mercury vapour fixture but this was uncommon. There was a market for street-lighting in France, many decades ago, as the lamp offered a pleasant light and energy was quite cheap. Due to the lamp operating restrictions as well as simple use, free standing or hanging mounting were quite common, even if lighting efficiency was diminished. | ||