Yesterday I asked a riddle about an unusual light bulb by asking where it is used Almost no one guessed.
The correct answer was given only by Alexander Tartyshevbut he clearly knew him. :)
This lamp with B22d base is custom made for the metro. Such lamps are used to illuminate stations and tunnels; they were made in Saransk at the Lisma plant.
The power supply for metro lighting is strange: the standard voltage is 127 V, but it can drop to 100 V. The emergency lighting is powered by 220 V. In order for the same bulbs to be used in both conventional and emergency luminaires, their driver supports operation in the voltage range of 100-220 V.
10 filaments were installed in the lamp, reducing their current by 10% of the nominal in order to increase reliability.
The lamps give light with a color temperature of 4000 K. According to the passport, they must provide a luminous flux of 1060 lm, in fact, they give 1100 lm.
These lamps have been used for a year in the Moscow and St. Petersburg metro stations.
P.S. I learned about these bulbs by accident: Facebook showed publication Lismas (I am subscribed to them).
© 2020, Alexey Nadezhin
The main topic of my blog is technology in human life. I write reviews, share experiences, talk about all sorts of interesting things. My second project - lamptest.ru. I test LED bulbs and help me figure out which ones are good and which are not.