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Flicker Free Flourescent Tube replacement. IT WORKS

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Flicker Free Flourescent Tube replacement. IT WORKS

Postby Andyp » 22 Aug 2017, 15:33

One of daughters has photosensitive epilepsy. We have been advised to replace the fluorescent tubes in our kitchen with LEDs as she has had a number of seizures in the kitchen and the lights could be a trigger. We have two side by side in ceiling mounted fitment.
If I understand correctly replacing the old tubes with LEDs is no guarantee to reduce flicker as they will still run off AC.
Again if I understand correctly the best way to reduce flicker is to either use incandescent bulbs (nearly impossible now) or go to a DC based system.
Am I chasing a holy grail or should I be able to obtain 1.2m DC LED tubes which I guess will require a DC transformer? Will the light output be similar to our existing daylight white tubes?

There seems to be a lot of claims and counter claims and even the epilepsy societies make conflicting statements.

Should I scrap the tubes and go for an alternative arrangement?

Any thoughts, experiences and suggestions welcomed.
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Re: Flicker Free Flourescent Tube replacment

Postby Tusses » 22 Aug 2017, 16:01

halogen is incandescent , and still available. ?

not sure on the light output, but you can get led tape and dc supplies.

if health is an issue, I'd ditch anything that is questionable .
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Re: Flicker Free Flourescent Tube replacment

Postby Malc2098 » 22 Aug 2017, 16:50

Andy,

I have had to look at the possible effects to people with photo sensitive epilepsy, and I have a family member who's suffers, so there was a personal as well as professional interest.

The first was relating to the siting of wind turbines. I cannot lay my hands on the research at the moment, but the speed at which the turbines revolved never exceeded 19 rpm so as flicker did not induce PSE.

The second was to provision of intelligent road studs within the road environment. IRSs are 'cats eyes' that are lit by LEDs that are powered from button cells charged via solar panels on the top of the stud, or in some cases, hard wired from an external power source. There was a complaint on a major road where these were fitted, that a sufferer, a passenger in a car, felt sick while being driven along the road. Others on this forum can state the frequency of the LEDs, but if there were any photo sensitive effect at all at that incident, then the consensus was the likely gaps between the studs and the speed at which the car was passing them, relative to sufferer's sensitivity. So, if there was a linked effect, again the consensus was that it was random because of the three factors, two of them, speed and sensitivity are likely to be different each time.

I'm not sure how much that might help, but the inference was that it was not the perceived flicker of the LEDs that contributed to the sufferer's feeling of sickness.

Hope that's some help.
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Re: Flicker Free Flourescent Tube replacment

Postby Tusses » 22 Aug 2017, 16:56

Malc2098 wrote:Andy,

I have had to look at the possible effects to people with photo sensitive epilepsy, and I have a family member who's suffers, so there was a personal as well as professional interest.

The first was relating to the siting of wind turbines. I cannot lay my hands on the research at the moment, but the speed at which the turbines revolved never exceeded 19 rpm so as flicker did not induce PSE.

The second was to provision of intelligent road studs within the road environment. IRSs are 'cats eyes' that are lit by LEDs that are powered from button cells charged via solar panels on the top of the stud, or in some cases, hard wired from an external power source. There was a complaint on a major road where these were fitted, that a sufferer, a passenger in a car, felt sick while being driven along the road. Others on this forum can state the frequency of the LEDs, but if there were any photo sensitive effect at all at that incident, then the consensus was the likely gaps between the studs and the speed at which the car was passing them, relative to sufferer's sensitivity. So, if there was a linked effect, again the consensus was that it was random because of the three factors, two of them, speed and sensitivity are likely to be different each time.

I'm not sure how much that might help, but the inference was that it was not the perceived flicker of the LEDs that contributed to the sufferer's feeling of sickness.

Hope that's some help.


I find them led cats eyes really distracting in the peripheral vision. ok head on , but the seem to "strobe" in th corner of your eye when you pass them .. I don't like it at all !
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Re: Flicker Free Flourescent Tube replacment

Postby Malc2098 » 22 Aug 2017, 17:04

That has been some of the complaints as well as, if they are bi-directional, their reflections in rear view mirrors.

However, that have more than proved their worth in reducing loss of control collisions on rural routes during the hours of darkness.
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Re: Flicker Free Flourescent Tube replacment

Postby greeno » 22 Aug 2017, 17:17

LEDs are all DC so you shouldn't have any worries.

The AC is always chopped into DC by something inside the unit.
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Re: Flicker Free Flourescent Tube replacment

Postby Tusses » 22 Aug 2017, 17:23

greeno wrote:LEDs are all DC so you shouldn't have any worries.

The AC is always chopped into DC by something inside the unit.


it's the chopping that could produce strobing.
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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 22 Aug 2017, 17:25

Malc, it is some help. Thanks. The whole subject is quite subjective and as far as my daughter is concerned and in the opinion of my missus the brightness of our kitchen lights could have as much an influence on seizures as the perceived flicker. Tiredness (always a problem in the morning) stress/anxiety as well was normal teenage girl growing up problems also play a part.

The two current tubes are 36W 865 lumens Cool daylight. We have tried warm white which was awful. I want to see if I can find some cool daylight with a lower lumen rating and replace the starters to see if it can have an affect.
Problem is encouraging a seizure to test a theory is not really on.
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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 22 Aug 2017, 17:37

greeno wrote:LEDs are all DC so you shouldn't have any worries.

The AC is always chopped into DC by something inside the unit.


This was my initial understanding too but a lot is dependent on the quality of the driver and the quality of the wall switch especially if a dimmer is used.
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Re: Flicker Free Flourescent Tube replacment

Postby TrimTheKing » 22 Aug 2017, 18:09

Very uneducated question but...lighting works on a frequency range, if you know that certain higher or lower frequency lighting affects her, and a higher/lower frequency doesn't, is the answer not to find an LED that operates at the highest/lowest frequency you can find and give that a whirl...?

I understand that means knowing the frequencies of what you have now, had before and will look at...

I appreciate if it was that simple then you wouldn't be asking but just thought I'd throw it out there.

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Re: Flicker Free Flourescent Tube replacment

Postby Robert » 22 Aug 2017, 18:27

Conventional (been around for years) control gear for fluorescents just regulates the mains current so it will operate at 50Hz and flicker. Electronic control gear (probably the only type you can buy now) operates at around 18KHz so it will have no flicker. So get a new fluorescent fitting if you want no flicker.
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Re: Flicker Free Flourescent Tube replacment

Postby Tusses » 22 Aug 2017, 18:38

Robert wrote:Conventional (been around for years) control gear for fluorescents just regulates the mains current so it will operate at 50Hz and flicker. Electronic control gear (probably the only type you can buy now) operates at around 18KHz so it will have no flicker. So get a new fluorescent fitting if you want no flicker.



surely it would have 18KHz flicker ?

just like young ears can hear 18KHz sound

I have no idea about the eyes and brain and flicker frequencies involved .

I know my laser cutter runs at about 25KHz , and DOES flicker. if you cut a line fast enough you can see the pulses in the cut.
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Re: Flicker Free Flourescent Tube replacment

Postby 9fingers » 22 Aug 2017, 18:50

If you do go down the DC supplied LED route beware dimmers which will chop the dc supply to re-create pulsed AC
It might be worth contacting the medics to see what range of frequencies cause the problem to your daughter and then armed with that info you can choose the lighting.

Low voltage filament lamp power supplies (wrongly referred to as transformers) also run on high frequency AC likely to be many 10s of kHz even over 100kHz

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Re: Flicker Free Flourescent Tube replacment

Postby Rod » 22 Aug 2017, 22:38

I fitted my shop with what I was informed were flicker free fluorescent double tube units from TLC.
They don't appear to flicker to my eyes.

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Re: Flicker Free Flourescent Tube replacment

Postby Robert » 22 Aug 2017, 23:25

Tusses wrote:I know my laser cutter runs at about 25KHz , and DOES flicker. if you cut a line fast enough you can see the pulses in the cut.


Surely if the laser was flickering at 25k you would see it when static and not just when cutting. The flicker when cutting must be down to reflections from the waste during the cutting process?

wikipedia says we cant see much past 60Hz

https://en.wikipedia.org/wiki/Flicker_fusion_threshold

There is a reference to 500Hz in extreme people in the notes..
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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 23 Aug 2017, 07:47

Quote from Epilepsy Org.uk

Most people with photosensitive epilepsy are sensitive to 16-25 Hz, although some people may be sensitive to rates as low as 3 Hz and as high as 60 Hz.


So as Robert points out control gear at 18khz (1800 hz) should not cause a problem. I have not yet checked the rating on our existing. I will have a look later.

I have just looked at the Chokes on TLC they all appear to be 240v/50hz. https://www.tlc-direct.co.uk/Main_Index ... ntrol_Gear so they are very much still available.

What I think I would need are High Frequency Ballasts https://www.bltdirect.com/philips-t8-36 ... le-ballast which interestingly are dimmable. Although trying to find a suitable dimmer switch is another nightmare.

So I am making progress but now confused as to whether improved flourescent or LED is the way forward.
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Re: Flicker Free Flourescent Tube replacment

Postby 9fingers » 23 Aug 2017, 08:01

Andy those chokes are just one of three components in an older style fluorescent ballast circuit and are stocked for maintenance purposes.
From a running cost vs light output there is a slight edge of led over hf ballast fluorescent. Up front costs are the opposite.
Dimming is a technical minefield and achieved in a variety of methods and vendors are unlikely to know or understand that level of detail in what they sell.
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Re: Flicker Free Flourescent Tube replacment

Postby Rod » 23 Aug 2017, 08:38

Like Trailing Edge dimmers.

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Re: Flicker Free Flourescent Tube replacment

Postby 9fingers » 23 Aug 2017, 09:01

Rod wrote:Like Trailing Edge dimmers.

Rod


Exactly Rod!

These imply use of the trailing edge of the mains cycle and so will likely exhibit 100Hz flicker (not 50Hz as incorrectly used in this thread so far)

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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 23 Aug 2017, 09:24

You two have lost me there.

Here are the chokes on the existing fitment

Image

I am guessing that what is important, as far as flicker is concerned, is the operating frequency.
Is there anyway I can tell the operating frequency which I am guessing is totally different from the line in frequency of 230V 50Hz which is clearly visible.
or am I getting it wrong?
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Re: Flicker Free Flourescent Tube replacment

Postby 9fingers » 23 Aug 2017, 09:29

Put your thinking head on Andy.

The supply is 50 Hz so the tube lights on the positive half cycle, goes out and then comes on again for the negative half cycle and so flashes at 100Hz.

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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 23 Aug 2017, 09:40

Ok, so what I have is not high frequency?

Just found this
Simply described, the (HF) ballasts contain three sections. A filter that protects the device from the irregularities in the mains supply and prevents RF and other interference to and from the ballast. A second stage that converts the 50Hz AC supply to DC and a third that consists of an inverter that supplies the lamp at high frequency with the correct voltage. This last section also includes a circuit that enables the preheating of the lamp where required and which is important for maximising lamp life.

Operating at anywhere between 20,000 and 40,000 Hz they consume up to 30% less power whilst producing the same amount of light. They are also quieter, lighter and have the potential for Dimming. There is no need for any additional components such as a starter or capacitor and this makes them quick and easy to install.


So should I be able to replace my existing chokes with HF ones?
I do not think therefore I do not am.

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Re: Flicker Free Flourescent Tube replacment

Postby 9fingers » 23 Aug 2017, 09:54

Andyp wrote:Ok, so what I have is not high frequency?

Just found this
Simply described, the (HF) ballasts contain three sections. A filter that protects the device from the irregularities in the mains supply and prevents RF and other interference to and from the ballast. A second stage that converts the 50Hz AC supply to DC and a third that consists of an inverter that supplies the lamp at high frequency with the correct voltage. This last section also includes a circuit that enables the preheating of the lamp where required and which is important for maximising lamp life.

Operating at anywhere between 20,000 and 40,000 Hz they consume up to 30% less power whilst producing the same amount of light. They are also quieter, lighter and have the potential for Dimming. There is no need for any additional components such as a starter or capacitor and this makes them quick and easy to install.


So should I be able to replace my existing chokes with HF ones?


Yes. Be aware that most HF ballasts run tubes in pairs. Your fitting appears to be a twin so that is fine.
Check the size of the HF ballast - usually convenient slim cross section - to make sure it fits inside the existing casing.
Sometimes the terminals are push in (once in never out) that require solid core wire. Your existing fitting will possibly use this sort of wire so retain the wire for reuse. the size required is not usually available as a diy item.
The HF ballasts are simply L,N&E in and four wires out to the tubes. They will only work with both tubes.
fitted. Have you spotted the problem?? When one tube fails, you don't know which it is so you need to juggle the new one with each of the old to get a working combination, or just change them in pairs.

Remove the chokes, power factor correction capacitors and starters.
Capacitors can be kept for motor replacements although low values only tend to be any good for sub horsepower motors.

Bob
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Re: Flicker Free Flourescent Tube replacment

Postby Tusses » 23 Aug 2017, 13:17

Robert wrote:
Tusses wrote:I know my laser cutter runs at about 25KHz , and DOES flicker. if you cut a line fast enough you can see the pulses in the cut.


Surely if the laser was flickering at 25k you would see it when static and not just when cutting. The flicker when cutting must be down to reflections from the waste during the cutting process?

wikipedia says we cant see much past 60Hz

https://en.wikipedia.org/wiki/Flicker_fusion_threshold

There is a reference to 500Hz in extreme people in the notes..


you can't see the laser .. it's invisible. But you can see the pulses in the finished cut, when the cutting head moves fast.

As for the wiki , frequencies you can see or perceive .. and what frequencies causes brain problems , they could be different ?. I.E. you might not be able to see the flicker, but it still might be affecting the brain. I don't know enough about it to say either way.. just to say I'd be cautious and not to rule it out, without knowing for sure.
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Re: Flicker Free Flourescent Tube replacment

Postby Andyp » 23 Aug 2017, 13:43

9fingers wrote:
Andyp wrote:Ok, so what I have is not high frequency?

Just found this
Simply described, the (HF) ballasts contain three sections. A filter that protects the device from the irregularities in the mains supply and prevents RF and other interference to and from the ballast. A second stage that converts the 50Hz AC supply to DC and a third that consists of an inverter that supplies the lamp at high frequency with the correct voltage. This last section also includes a circuit that enables the preheating of the lamp where required and which is important for maximising lamp life.

Operating at anywhere between 20,000 and 40,000 Hz they consume up to 30% less power whilst producing the same amount of light. They are also quieter, lighter and have the potential for Dimming. There is no need for any additional components such as a starter or capacitor and this makes them quick and easy to install.


So should I be able to replace my existing chokes with HF ones?


Yes. Be aware that most HF ballasts run tubes in pairs. Your fitting appears to be a twin so that is fine.
Check the size of the HF ballast - usually convenient slim cross section - to make sure it fits inside the existing casing.
Sometimes the terminals are push in (once in never out) that require solid core wire. Your existing fitting will possibly use this sort of wire so retain the wire for reuse. the size required is not usually available as a diy item.
The HF ballasts are simply L,N&E in and four wires out to the tubes. They will only work with both tubes.
fitted. Have you spotted the problem?? When one tube fails, you don't know which it is so you need to juggle the new one with each of the old to get a working combination, or just change them in pairs.

Remove the chokes, power factor correction capacitors and starters.
Capacitors can be kept for motor replacements although low values only tend to be any good for sub horsepower motors.

Bob


The missus wouldn't mind keeping the existing fitting and bulbs so I am prepared to give it a go especially if it is as easy to fit as you describe. Can't see any power factor correction capacitor, just existing chokes and starters. The starters I reckon on leaving in place but disconnecting as the holes will show otherwise.

Having them dimmable seems like a good idea but I am struggling to understand which dimmer switch would be suitable and then to find one over here.
I do not think therefore I do not am.

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