Difference between revisions of "Osram HWL"

Slightly major 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. It should be noted that, due to the lamp's construction, light output is not uniform, with noticeable segregation in colour and intensity between the center and tip of the lamp. Although this effect is not severe, it may be a slightly unpleasant effect in certain situations.

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 filament 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 occurred in the 1970s. Many years have passed since use of this lamp was basically non existent, 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 fluorescent 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.