Patrick
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There are troffers in my office with 3xF32T8 lamps. They start up exactly like magnetic rapid start. If one lamp fails, they all glow dim just like magnetic RS, except with magnetic there would typically only be two lamps in series. Clearly they're not instant start, and I thought programmed start caused the ends to glow at startup like preheat (but without the blinking). Are they a kind of electronic rapid start and why aren't they destructive at EOL like most electronic ballasts? If they had EOL protection, I'd expect the lamps to cut out entirely, not glow dimly.
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« Last Edit: December 06, 2012, 10:02:21 PM by pjc »
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Patrick C., Administrator Lighting-Gallery.net
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funkybulb
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It could be real magnetic rapid start ballast. single and two lamp ballast being Used? i do have a 2 lamp magnetic F32 rapid start.
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No LED gadgets, spins too slowly. Gotta love preheat and MV. let the lights keep my meter spinning.
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Patrick
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I've seen several burn out, and all three lamps always go at once, so it must be a single ballast. Sometimes flipping off and on the wall switch will get a dim fixture to come on. Again, much like the behavior of magnetic RS.
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DetroitTwoStroke
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It sounds like they are Motorola electronic rapid start ballasts. My old high school had four lamp Motorola ballasts running GE T8 w/Starcoat F32T8/SP35 full mercury tubes and Philips Alto F32T8/TL735. When one lamp failed, all four would glow dimly. The OCV isn't high enough to heat the electrodes to vacuum loss, so they just glow dimly like magnetic RS. Motorola also made instant start ballasts that, as far as I know, behave like any other IS ballast. Motorola ballasts were made in the U.S.A. until they were bought by Osram Sylvania in the early 2000s, and production shifted to China.
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Pride and quality workmanship should lie behind manufacturing, not greed.
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dor123
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Usually, if one lamp fails in a 2-4 lamps electronic ballast of any type (Instant-start, rapidstart, PTC and programmed start), all of the rest lamps should go out (Unless I'm miss something about the operation principle of the american electronic rapidstarts: Perhaps they actually don't relys on a starting capacitor for starting, with or without a mechanism to delay its operation to preheat the electrodes [Like PTC or a smart preheat circuit], like the rest types of electronic ballasts, but operating with the same mechanism of the magnetic rapidstarts [A heating transformer and capacitor]).
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I"m don't speak English well, and rely on online translating to write in this site. Please forgive me if my choice of my words looks like offensive, while that isn't my intention.
I only working with the international date format (dd.mm.yyyy).
I lives in Israel, which is a 220-240V, 50hz country.
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Ash
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First lets detrmine if it is magnetic or electronic - by the 120 hz flicker
Now can you see hw the lamps are wired ?
There is nothing preventing to make a 3 lamp series RS (with all 3 lamps in series) - it'd need 2 more "yellow wires" and higher OCV thats all
And there is nothing preventing this from being electronic. Same transformer layout and everything, but input to the transformer is HF instead of direct 120v 60 hz, and the transformer small ferrite like in all HF transofrmers
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Patrick
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mrboojay
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One way to tell if it is magnetic or electronic could be to hold a camera (i.e. a cell phone) up to the light and wait for it to lower the exposure level. Than look to see if there are any orange or black lines that appear. If they do than it is megnetic, if not and you can see the tubes like with the human eye than it is electronic. This is the case for every camera and ballast I have tried. Here is a picture to show what it would look like.
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« Last Edit: December 08, 2012, 12:39:28 PM by mrboojay »
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Ash
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Not exactly. The camera detects 100/120 Hz flicker. But how about this :
Resistive ballast have even worse flicker than magnetic
Low frequency electronic ballasts can have flicker - There are capacitive ballasts, "dimmers", ballasts with rectifier and whatnot
Capacitor-less HF electronic ballast will have sigificant flicker
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