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Lamps => Modern => Topic started by: dor123 on February 03, 2015, 07:26:27 AM

Title: Very long time for the cutout of the Philips SON-I 70W to close. Why?
Post by: dor123 on February 03, 2015, 07:26:27 AM
Today (3/2/2015 DD/MM/YY), I've seen in the third time in my life, a Philips SON 70W with internal ignitor, cycling inside an AEG Koffer 70 that located at Qiryat Frostig neighborhood, above the recycle bin, and capture some videos.
Like the one at  Stella Maris  (http://www.lighting-gallery.net/gallery/displayimage.php?pos=-96736), and the one at  Kibbutz Ein-Gev  (http://www.lighting-gallery.net/gallery/displayimage.php?pos=-99954), the cycling one inside the Koffer 70, here in Qiryat Ata, also takes a good 4-5 mins for the thermal cutout of the starter to close, so the starter can restrike the lamp at a dim bluish mercury color (Regardless of the sodium-mercury amalgam ratio), and with the flickering associated with cold ignition.
Why the Philips SON-I 70W, have to cool down to very low temperatures to connect the bi-metal, resulting in a very long cooling down period? Why Philips didn't setted the bi-metal to close at higher temperatures, so to hot restike the lamp after a shorter time (2-3 mins)?
Title: Re: Very long time for the cutout of the Philips SON-I 70W to close. Why?
Post by: Medved on February 03, 2015, 03:44:51 PM
Once the starter is not able to ignite the lamp, it get destroyed pretty quickly.
And hotter the lamp, more difficult is to ignite it.
So that mean setting the thermal cut out low means the lamp must really cool to reclose means once the starter is connected back, the lamp is already properly cold, so if it is still in working condition, it will ignite virtually for the first starter kick, so the starter wear is minimized.
Of course that means it takes longer to cool down, but that is usually not that big problem.
And once the lamp starts to cycle, it does so way slower, so it becomes less annoying...
Title: Re: Very long time for the cutout of the Philips SON-I 70W to close. Why?
Post by: dor123 on February 03, 2015, 10:45:25 PM
I've seen internal ignitor HPS lamps with much shorter cooling down before the thermal cutout connects: Osram NAV-E/I 70W, which cools down for 2 mins to connect the starter, as well as  Sylvania Ecoarc 69/108W retrofit for MV lamps  (https://www.youtube.com/watch?v=dp7Y2qKSuLs), which in the video, connected the thermal cutout after only a min, but the user operated it on 40W T12 (0.70A) ballast.
Title: Re: Very long time for the cutout of the Philips SON-I 70W to close. Why?
Post by: Medved on February 04, 2015, 12:40:03 PM
If you operate the lamp at 0.7 instead of 1A, it runs way colder, so no wonder it takes shorter time to cool down to reclose.
But what I was describing is a motivation for the manufacturer to set the contact to lower temperature. Other may have preferred the shorter restrike time and sacrifice the starter when the lamp wears off more, so set the temperature higher.