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Short Time Running Of Fluorescents

Posted: Tue Aug 22, 2017 12:38 am
by Paul
Is there any detriment to the lamp if it is run for a relatively short period, say 20-30 mins at a time? If a lamp hasn't been fired up in a while, should it be considerably longer, a bit like some discharge lamps?

Re: Short Time Running Of Fluorescents

Posted: Fri Aug 25, 2017 10:53 pm
by Slyspark
Have to admit, I've wondered the same. I'm sure it won't do them too much harm (unlike old SOX / SLI lamps) but repeated switching versus occasional switching with long burning hours will slightly reduce the life of the tube. I can't see why never running it for more then 20-30 mins would be a problem tho.

Re: Short Time Running Of Fluorescents

Posted: Sun Aug 27, 2017 7:33 am
by LinearSLI-H
GE say that discharge lamps need at least a 10 hour run on each switch on, less than 10 hours reduces life by 25% for each burning cycle.
Having said that, I don`t think it will harm fluorescents with just a half an hour run per start, and with the use of electronic starters to `soft start` any tube, I reckon you will still get a good life from them.

Re: Short Time Running Of Fluorescents

Posted: Tue Apr 24, 2018 4:57 pm
by MFL
Fluorescent lamp life decreases with switching cycles. The standard 3h switching cycles are 2h45 on, 15 min. off to achieve the expected life of 10000h to 15000h. According to Sylvania technical data, lamp life is reduce to 50% with 3 time more switching cycles per day (30 vs 10 switching cycles/day). I found on a belgian website that fluorescent lamp life is only 4000h to 6000h with 6 minutes switching cycles versus 12000h to 15000h with 3h switching cycles.
The storage time doesn't affect lamp life as far as I know

Re: Short Time Running Of Fluorescents

Posted: Sun Apr 29, 2018 10:18 pm
by WHERESTHECUEBALLGOIN
LinearSLI-H wrote:GE say that discharge lamps need at least a 10 hour run on each switch on, less than 10 hours reduces life by 25% for each burning cycle.
Having said that, I don`t think it will harm fluorescents with just a half an hour run per start, and with the use of electronic starters to `soft start` any tube, I reckon you will still get a good life from them.


Ten hours a time seems wholly impractical, when you say "discharge lamps" do they include fluorescents in that, or do they mean it to be HID and similar? Many offices won't even run for 10 hours a time, and it's worse in places where they're on PIR switches to go off after a predetermined length of time. The college I went to in 2007 had lamps on PIRs, so I know that's been around for a bit.


MFL wrote:Fluorescent lamp life decreases with switching cycles. The standard 3h switching cycles are 2h45 on, 15 min. off to achieve the expected life of 10000h to 15000h. According to Sylvania technical data, lamp life is reduce to 50% with 3 time more switching cycles per day (30 vs 10 switching cycles/day). I found on a belgian website that fluorescent lamp life is only 4000h to 6000h with 6 minutes switching cycles versus 12000h to 15000h with 3h switching cycles.
The storage time doesn't affect lamp life as far as I know


The starter type affects lamp life as well. Sure, if you're frequently starting and stopping a 20W T12 on an FS2 I'd expect it to die quicker, especially given T12s often don't live as long as T8s and FS2 starters can be quite lively, particularly Philips S2 which in my experience are epilepsy inducers. I am told however that lamp life can be transformed with good quality electronic starters, most noticeable over short run times where they're much friendlier to the cathodes. You also have to consider electronic soft-start with modern T8s that last an eternity; where it isn't uncommon to see lamps run and run until they're merc starved, or just plain outlasting the control gear.

I have a 2x18W setup which generally gets started 2-3x a day, but only runs during the period where I need to prepare food or wash up. It's also the kind of application where when I want the light I want it NOW, so in this particular case I can't be arsed with a lazy starter, and so the 2x ultra fast electronic starters I have in there fit the bill perfectly. Now, a "dyed in the wool" collector might say it's completely the wrong application for fluorescent... but I like it. The light comes nearly instantly on and after a year of operation like this there is absolutely no sign of wear on the tubes. Such infrequent use, even despite frequent starts, obviously works in favour of overall lamp longevity, and I honestly wouldn't be surprised if my next relamp is when I'm much older! (very quick and dirty math: 15000 hours [or more, since modern T8s last nearly forever] divided by 730 [two hours runtime per day average, over a year] = just over 20 years).

One of the reasons I'm not at all afraid of using fluorescent lamps as a collector, is I reckon my odds of accidentally breaking a lamp are probably higher than it wearing out through occasional use.

Re: Short Time Running Of Fluorescents

Posted: Mon Apr 30, 2018 7:28 pm
by LinearSLI-H
The ten hours thing is noted in the GE lamp guide for Lucalox lamps only, took me a while to find it again!

Re: Short Time Running Of Fluorescents

Posted: Tue May 01, 2018 12:10 am
by WHERESTHECUEBALLGOIN
LinearSLI-H wrote:The ten hours thing is noted in the GE lamp guide for Lucalox lamps only, took me a while to find it again!


Thought as much. Was gonna say, that's unrealistic expectations for fluorescents!

Re: Short Time Running Of Fluorescents

Posted: Wed May 02, 2018 2:09 pm
by MFL
Ten hours is not unrealistic expectations for fluorescents in professionnal use : I work in a library and lights are on from 6 or 7 am to 6 pm in most rooms so nearly 12 hours cycles ! In private use, you're right, it's not common

Re: Short Time Running Of Fluorescents

Posted: Wed May 02, 2018 3:53 pm
by MissRiaElaine
The lights in my office before I left were on all day, it was a very dark location with virtually no daylight.