Swirling in Fluorescent Tubes « on: January 15, 2010, 11:47:05 PM » Author: Bamaslamma1003
I have some new Philips TL850 F32T8 lamps. I turned them on and after a few hours, there was a swirling effect. What causes this? It's a cool effect. I've also seen some of my F40T12 lamps do it as well. The F32T8 ballast I use is a rapid start magnetic ballast made by Universal.
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	Re: Swirling in Fluorescent Tubes « Reply #1 on: January 16, 2010, 11:13:24 AM » Author: dor123
I also saw the swirling effect in T12 40W lamp on switch start magnetic gear, as well as in my 3W compact fluorescent nightlights using simple capacitive ballast. I also don't know what cause this, but one thing about the F32T8 lamp: according to www.lamptech.co.uk site of james hooker, T8s can be operated ONLY by switch start ballasts or HF electronic ballasts and not by another type of magnetic ballast because the argon-krypton gas mixture in them cause them to require somewhat higher starting voltage then the T12s
« Last Edit: January 16, 2010, 11:15:13 AM by dor123 »		Logged

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	Re: Swirling in Fluorescent Tubes « Reply #2 on: January 16, 2010, 02:11:13 PM » Author: Bamaslamma1003
What is switch start? The ballast I use is a magnetic rapid start ballast actually made for F32T8 lamps rather than running them on an F40 rapid start ballast which I have also done many times. My F32T8's seem to start up just fine on F40 ballasts. They just strobe a little until they warm up. I'm thinking it may be because these lamps don't have a lot of hours on them yet. I've also done the reverse, running F40's on the F32 ballast. They start up just fine. They are just slightly dim due to being underdriven by 20%.
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	Re: Swirling in Fluorescent Tubes « Reply #4 on: January 17, 2010, 05:28:59 AM » Author: dor123
Switch start is a magnetic ballast that works in combination with starter which preheats the electrodes before the ballast can ignite the lamp. It is the reason whay in the US it called PREHEAT, because another type of US magnetic ballasts (Includes rapid start) doesn't preheat the electrodes. T8 lamps can't start on rapid start magnetic ballast and therfore there is no rapid start magnetic ballast anywhere in 220V+ Countries. In Israel Eltam producted rapid start magnetic ballasts for use with T12s only 20W and 40W in the past, but ceased the production of them when the importing of T12 to Israel declined in favor of preheat ballasts with internal electronic starter called Perfectstart. Today the only rapid start ballast in Israel is for US HO T12 110W (Phillips ALTO daylight usually).
« Last Edit: January 17, 2010, 05:31:32 AM by dor123 »		Logged

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.

	Re: Swirling in Fluorescent Tubes « Reply #6 on: February 02, 2010, 09:19:56 AM » Author: dor123
I think the reason Bamaslamma1003 can be light his F32T8 tube with a rapidstart ballast that espacially designed to operate the lamp despite it is T8 is because it is probably just an old argon based fluorescent tube and not the modern argon-krypton. In Europe they have two argon T8 fluorescent tubes in 15W and 30W which is almost totally obsolete. In the US there was probably also argon T8 tube but in different wattages. However theoretically rapidstart ballast (Magnetic) can't ignite Krypton filled fluorescent tubes. Only Preheat/Switch Start ballasts and of course electronic ballasts.
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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.

	Re: Swirling in Fluorescent Tubes « Reply #7 on: May 09, 2010, 12:06:20 AM » Author: RCM442
umm ALL F32T8 fluorescent lamps contain argon, dor123, he said his ballast was MADE for F32T8 lamps, they did make magnetic ballasts for F32T8 ballasts before! and he happens to have one!
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	Re: Swirling in Fluorescent Tubes « Reply #8 on: May 09, 2010, 01:56:37 AM » Author: Medved
Arc swirling i observe mainly in newer (Ar+Kr T8) lamps, when they are long time not in use and before they heat up. It happened on both HF electronic and LF serial inductor ballasts. After few burning hours the effect disappear, even when switched OFF. And again, when longer time (few weeks in cold) not in use, the effect appear again. Maybe mercury settle somewhere and has to diffuse back, cause the lamp being temporary mercury starved? Or gravity separate the gas fill components, so they have to mix up again?
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	Re: Swirling in Fluorescent Tubes « Reply #10 on: May 09, 2010, 02:13:56 PM » Author: xmaslightguy
Quote from: joseph_125 I believe running them on a preheat ballast or a F40 only NPF rapid start ballast will cause the ballast to overheat Yep running even one of those 34w lamps on a Rapid Start LPF (or NPF) ballast will cause the ballast to overheat (& the thermal protection to shut it down) I've had that happen multiple times (now i always double check that i grabbed a real F40 lamp before installing it in any shoplight with one of those ballasts) I've seen that swirling/snake effect on new bulbs (T12 & T8) as well, always goes away with some use.
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	Re: Swirling in Fluorescent Tubes « Reply #12 on: May 22, 2010, 01:51:19 AM » Author: Medved
It is described as an acoustic resonance within the tube and avoiding it lies in minimizing "the peaks" in ballast frequency spectrum, mostly by operation frequency jitterring. Cheapest "CFL like" ballasts (ferrite ring controlled two transistors) do this intrinsically, as they tend to keep the current constant, what mean the frequency is modulated by ripple on the intermediate DC bus. This problem mainly come with ballast using more advanced control IC's, what in "run" mode use fixed frequency. Then it disappeared again with dimming ballasts: The reason is, then these regulate the current by some feedback loop controlling the frequency, so it is then modulated by the DC bus ripple as well (the regulation compensate varying voltage by changing the frequency, to keep lamp current constant). So these "anti-striation" ballasts are technically dimming ballast, only with the setting fixed to full power. But the effect happen even at low (mains) frequency ballasts on some lamps, but usually only when the lamp is cold and disappear after warm-up. May be it is linked to mercury content - as mercury emit lot of (UV) light during the discharge, it's presence is a dissipative element in the "resonance" system, so it reduce the "Q" so, the striation is less likely to happen.
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	Re: Swirling in Fluorescent Tubes « Reply #14 on: May 24, 2010, 04:47:25 PM » Author: Medved
Even if something is "patented", you can find not as difficult way around. It would be principally the same, however formally different. Usually the basic stuff is not possible to patent, you might practically patent only certain implementation. But there are plenty of possibilities to remove some insignificant part and that mean, then it does not match patented claims... So here you might use or arbitrary frequency sweeping, or switching between different frequencies, use current regulating feedback for fixed current, so the frequency would vary with the DC bus voltage ripple, modulate the target current, as modulation signal use triangle, or sinewave, or something like arctg wave - even if all result practically the same, only some might be patented - e.g. the arctg-like frequency sweep of SMPS is patented (by i gess OKI) for EMC emission control, as the "best shape", however other shapes give results <1dB worse, what is nearly no difference for real life (the required supression is usually in 10's of dB...)
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