Lighting-Gallery.net
Lamps => Modern => Topic started by: RyanF40T12 on October 01, 2011, 05:24:04 AM
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A new church building constructed 2 years ago. The electrical contractor put in Philips 700 Series F40T8s throughout the building, and either it was a bad batch from Philips, or the ballasts are zapping them. Less than 4000 hours on the lamps and they are all starting to go now. Had a few over the past few months and even year, but now I'm changing out 5-10 lamps a week, at least the ones I can reach. The ones in the Gym and chapel will require a lift. Going to get them all at once when I get up there. Replacing with Sylvania 4100Ks. Seem to have very good luck with those. We had a power generator hooked up to the building when it was under construction because the local power utility had not yet been able to run the underground line up to the building. I am wondering if that had something to play with these early failures.
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On a side note, I've been swapping in the burned out bulbs with some used Philips 4100s from an older building that we are converting over to cool white due to the new carpeting and wall paper which picks up white tones better. Will post some photos tomorrow.
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If the generator was running at wrong frequency it can cause damage to the lamps on magnetic ballasts :
Too low frequency : balast impedance too low so overdriving the lamp + ballast overheating + longer delay at each zero crossing so probably cold cathode condition
Too high frequency : ballast impedance too high so underdrivig the lamp and cathodes are cold
On electronic ballasts i think the ballasts would blow if there is a problem, but not make the lamps blow
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Thanks for the info. These are all electronic ballasts. Did some pondering and thinking and really do suspect a bad batch of bulbs from Philips, or with the 700 series, the filaments are not as strong from the factory thus leading to easy failure. See below.
One of the 100+ that have burned out with less than 4000 hours. Some as few as 500 hours I am guessing:
(https://www.lighting-gallery.net/proxy.php?request=http%3A%2F%2Fi143.photobucket.com%2Falbums%2Fr160%2FWattsWattsWatts%2FBulbs%2FIMG00026-20111002-2339-1.jpg&hash=6c376ec4a1384c525b21321b001875836049cd7f)
Here is one of the 700 series in use in the fixture. Note the part of the filament that has fallen. This bulb will be going out within the next week I am sure.
(https://www.lighting-gallery.net/proxy.php?request=http%3A%2F%2Fi143.photobucket.com%2Falbums%2Fr160%2FWattsWattsWatts%2FBulbs%2FIMG00028-20111002-2340.jpg&hash=a53df2740a36674dd2fac3c8007f617d58cb35d9)
Here are some 5-6 year old Philips TL730s that I removed from one building and am putting these in the building that the 700 series are burning out in as I want to keep the warm white color in the newer building where as we can go with the cool white colors in the older buildings, due to the wall and carpet colors.
(https://www.lighting-gallery.net/proxy.php?request=http%3A%2F%2Fi143.photobucket.com%2Falbums%2Fr160%2FWattsWattsWatts%2FBulbs%2FIMG00029-20111002-2344.jpg&hash=077b3f2968ab20ad5d1bc41edd7a1c615a6267d7)