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Fluorescent ballast minimum working temperature
Posted by
Back2Volts
on 14 Aug, 2017 18:01
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The ballast of one of the 2xT8 lamps in the garage died. I have replaced it with one from a new lamp that was pending installation. Now, looking for a consumer replacement, I found one Class-B that has a minimum starting temperature of -18C/0F. What happens if the temperature goes any lower ? It is just that is does not start the tubes ?
Tony (in Minnesota)
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My garage tubes don't like starting in the cold and I am only in the UK, sometimes a new starter helps but also it's a sign the tubes may need replacing. If your place is really cold it might be worth adding an incandescent or LED lamp just for that eventuality.
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#2 Reply
Posted by
Back2Volts
on 14 Aug, 2017 19:28
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Yes, I do have some incandescent in there too.
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#3 Reply
Posted by
floobydust
on 14 Aug, 2017 19:32
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At low temps the tube's firing voltage and resistance go up, so the ballast has to work harder.
With magnetic ballasts, I can flick power on/off many times until the tube lights, but super dim until the gas warms up, but still dim.
CCFL's are the same, barely usable outdoors in winter. I'm talking -20C or colder.
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#4 Reply
Posted by
Wirehead
on 14 Aug, 2017 19:46
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Time for some LED's. Bonus: the colder, the more light
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I've turned mine on in -30's, what I found is that they are just not as bright. They slowly increase brightness over time, I presume, but did not really notice. I've found that CCFLs are the same, even inside the house if it's like 10C they won't be as bright as when it's like 20C. Though CFLs seem to require a warm up time no matter what.
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#6 Reply
Posted by
Gyro
on 15 Aug, 2017 10:19
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Not that it's likely to help anyone much these days but Philips had two different filling for florescent tubes for different temperature ranges. For reliable starting and decent light output below 0'C they used Argon filling and for room temperature, Krypton.
I'm lucky enough to still have a couple of 8ft Argon filled florescents running happily in the garage. Nice and bright at all temperatures.
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#7 Reply
Posted by
Halcyon
on 15 Aug, 2017 10:47
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I think the only place cold here is a freezer.
That said, a 34 degree day in the UK is a "heatwave", here it's called "summer".
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#8 Reply
Posted by
Vtile
on 15 Aug, 2017 10:56
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#9 Reply
Posted by
Zero999
on 15 Aug, 2017 17:48
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#10 Reply
Posted by
SeanB
on 15 Aug, 2017 19:22
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I lived in a town where 34C was simply 7AM in summer and in winter 8AM. It got warmer from there, going to an average of 41C every day. You could give a weather forecast for the year as sunny and hot every day.
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#11 Reply
Posted by
Kleinstein
on 15 Aug, 2017 19:49
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The ballast itself usually should not have a problem with low temperature - maybe avoid moving the wires when very cold. However the tubes tend to be more dim and may not start properly. Besides a low temperature, high humidity and high altitude could be a problem too. Some are specified to maximum of 2000 m / 7000 ft - this can be a problem it parts of the US. Also the combination of high temperature and high altitude can get tricky, as cooling gets less efficient.
For cold temperatures LEDs are a good choice. Up to the point of not bothering to replace a broken fluorescent with a new one, but used LEDs instead.
Low temperatures can be a problem to electronic ballasts through - electrolytic caps don't like them very much.
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I lived in a town where 34C was simply 7AM in summer and in winter 8AM. It got warmer from there, going to an average of 41C every day. You could give a weather forecast for the year as sunny and hot every day.
That's insane, here 25C is pretty much a heat wave, we get the odd 30C+ Not sure what the all time record is, maybe like 35. I was down south in Toronto area when it hit 39 once. That was insane, even for there. We were at Canada's Wonderland, rides were making us nauseous because of the heat so we went in the water park. Was still brutal. Sunburned so bad that day too. That was definitely not a ginger friendly day to be out in the sun lol.
I think I would spontaneously combust if I went to the deep south where it hits in the 40's.
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#13 Reply
Posted by
meeko
on 18 Aug, 2017 21:06
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I was down south in Toronto area when it hit 39 once.
Yeah, 39 here in Toronto is really unpleasant, because chances are it's also humid. Luckily it hasn't been too bad this year, mostly twenties to low-thirties.
On the other hand, it was 45 when I went out to the desert in Dubai, and it wasn't that bad, because of the very low humidity.
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#14 Reply
Posted by
G7PSK
on 18 Aug, 2017 21:23
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My workshop has 12 triple tube quick start fluorescent lamps and in winter at around or below freezing they wont start until I touch them with a long metal pole which I then drag from one end to about three quarters along, the light follows the pole up to that point then jumps to the end. The tubes have been changed the ballasts replaced and even some of the units completely replace but the problem persists. At some point they will have to be replaced with LED's but as of yet I have not found ones that can be connected to 3 phase power which I require for ant-strobe purposes with lathes etc.
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#15 Reply
Posted by
David Hess
on 19 Aug, 2017 02:35
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I replaced the LC ballasts in my garage shoplights with electronic ballasts and they start much better in cold (below freezing) weather although the bulbs take 10s of minutes to reach full brightness. They make special electronic ballasts for operation at even lower temperatures.
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I have many 8 foot fluorescents in my shops. The cost of replacing the ballasts is so high that any failures will result in replacement with LED lights. I will probably have mixed lighting for decades.
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#17 Reply
Posted by
SeanB
on 19 Aug, 2017 05:31
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My workshop has 12 triple tube quick start fluorescent lamps and in winter at around or below freezing they wont start until I touch them with a long metal pole which I then drag from one end to about three quarters along, the light follows the pole up to that point then jumps to the end. The tubes have been changed the ballasts replaced and even some of the units completely replace but the problem persists. At some point they will have to be replaced with LED's but as of yet I have not found ones that can be connected to 3 phase power which I require for ant-strobe purposes with lathes etc.
Easy to retrofit the flourescent lamps with LED. Just make sure that your lamps have 3 phase plus neutral available ( important to have the neutral in good condition) and just replace each lamp with LED and you are done. Likely you have an instant start ballast per lamp, probably a potted resonant ballast that drives 2 lamps, and which likely is driving T12 lamps as well. In that case just buy LED lamps, and look at how those are wired, and disconnect the ballast and wire in the lamps. Easy to leave the ballasts in the fixture as well, or undo the 2 small nuts and remove them. If electronic ballasts and T8 lamps the same, and if T5 you will need new end holders as well.
Wire each fixture with one phase and neutral, and you will be fine, and if you have 3 lamps per fixture then it is easy to just have one phase per lamp.
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#18 Reply
Posted by
tronde
on 19 Aug, 2017 14:57
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My workshop has 12 triple tube quick start fluorescent lamps and in winter at around or below freezing they wont start until I touch them with a long metal pole which I then drag from one end to about three quarters along, the light follows the pole up to that point then jumps to the end.
You can add a thin metal wire from end to end of the tube. It will increase the ability to ignite in low temperatures. The attached images shows comercially available tubes with a conductive stripe on the glass. Some manufacturers connect it to the metal end-caps, some not.
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#19 Reply
Posted by
Gyro
on 19 Aug, 2017 17:42
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Those tube with strips used to be used on instant (resonant) start and dimmable florescents too. The dimmable ones used separate windings to keep the filaments hot during dimming. So basically yes, any situation where starting would be more difficult than usual.
At a pinch I've even seen it done with fusewire in a loose spiral around the tube!
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#20 Reply
Posted by
SeanB
on 19 Aug, 2017 17:58
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The tubes with a starting connection typically are also only available in T12 or larger sizes, and are pretty much not made any more these days. Never seen a T8 or smaller with a starting strip. In the examples shown one is a regular bipin tube, T12 with the end cap designed to be a contact in the holder and grounded, connecting the tube strip to the chassis ground deliberately.
The other is a single pin designed for a similar use, as it typically was used in EEX rated fixtures, which had a limit on allowed open circuit voltage so that the starting strip was required to get a high enough voltage gradient to start the tube with an open circuit voltage of 400V in the ballast. The long pins are designed as well to allow the tube connector to be part of the safety system, with them closing a contact to allow ballast power only when fully inserted, and if broken disconnecting power to the ballast. The cover is also part of the safety system, as it has interlocks that disconnect line and neutral power connections at the cable entry when you start to undo and remove the power, so that you can change the tubes even energised, with a lower risk of explosion from arcing, and the interlocks also protect if the cover is broken along with the tubes, as the broken tube means the ends are ejected and the power disconnected with the switch contacts still enclosed so any arc is contained in the connector.
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#21 Reply
Posted by
tronde
on 19 Aug, 2017 19:34
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I have used "normal" 2-pin 36W T8 tubes with stripe. Some of them connected to the end-cap for possible grounding, and some without. None of them had separate filaments. As Gyro said, you can wind a wire as a spiral, and it is possible to connect it to ground. Just clip it to a metal part of the fixture. This was quite normal to do when dimming with an inductive ballast. I have also seen special metal mesh "tubes" to have around the fluorescent tube to help ignition and reduce flicker when dimmed. It cost almost nothing to wind some thin wire around the tube, and it will most likely help alot. If it is cold, it helps on the light output to have a closed fixture so the tube becomes heated by its own energy loss.
Since modern electronic ballasts dim with PWM, and they also have a much better control over the ignition than inductive ballasts, tubes with stripe has become rare, but it is perfectly OK to make your own. You don't need to have the wire connected to the end cap if you fear for shorting something. Cold climate and reduced level of mercury in the tubes is not the best combination, so sometimes we must give the ignition a helping hand.
..This summers peak here 25 deg.C one single day.