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#1
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Fluorescent light and starter question.
Hi all,
So, I have a couple of 6' single TL-D 70W tube fittings in the kitchen and the other day one started flickering. I had a box of new tubes so replaced them both (they were due anyway) but one still wasn't right. I found a spare starter and replaced the iffy one and all was well. I ordered a cotchel of 4-80W basic starters cheap from ebay and when they arrived, replaced both in the fittings and initially all seemed well. Then a couple of evenings later the Mrs reported one was randomly blinking off and then seemed to do so nearly constantly. Replacing that starter with an old Philips 70-125W one had everything stable again ... until, the other new starter fitted lamp started blinking off. ;-( So, I bought a small cotchel of electronic starters, replaced the kitchen ones again and they have been fine ever since. ;-) So, after running the situation past the eBay seller of the first starters we have been having a discussion where he seems to think that it could be anything but the starters ... and I think it could be that the starters are a bit underrated ... and so the range of voltages seen across the starters are sometimes too much for those particular items and hence why they are re-triggering, even when the tube is running fine? So panel, anyone experienced anything like this before and what was it? Is it just that 70W is on the upper end of a starter rated as 4-80W, especially a cheap one? One of the same two starters runs a 40W tube / fitting fine. To add a bit more fuel to the fire. I thought I'd also test the other 4 new starters on the tubes when they were cold. The first caused the tube filaments to glow but the tube didn't even try to start. The next two caused the tube to try to start but not actually manage it. The last did allow the tube to fire up, as then did the previous two but once the tube was already warm? Putting one of the electronic or one of the old Philips 70-125W starters back in will start the same tube from any situation. Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Cheers, T i m |
#2
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Fluorescent light and starter question.
On 20/04/2018 18:51, T i m wrote:
Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. The starter is a one shot process. Once the tube is lit it has no further use. -- Adam |
#3
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Fluorescent light and starter question.
On Fri, 20 Apr 2018 21:04:20 +0100, ARW
wrote: On 20/04/2018 18:51, T i m wrote: Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. It works fine till you turn it off again. ;-) The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. Cheers, T i m [1] The diffusers yellowed and the end plastics went brittle so I may have bought new (slimline) fittings (Fitzgerald?) somewhere along the line. |
#4
Posted to uk.d-i-y
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Fluorescent light and starter question.
On 20/04/2018 21:25, T i m wrote:
On Fri, 20 Apr 2018 21:04:20 +0100, ARW wrote: On 20/04/2018 18:51, T i m wrote: Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. It works fine till you turn it off again. ;-) The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. Cheers, T i m [1] The diffusers yellowed and the end plastics went brittle so I may have bought new (slimline) fittings (Fitzgerald?) somewhere along the line. Voltage drop to the house? -- Adam |
#5
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Fluorescent light and starter question.
On Fri, 20 Apr 2018 21:55:35 +0100, ARW
wrote: snip The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. snip Voltage drop to the house? Well, that's the sort of thing I am open to but if I understand it right, the ballast and tube are in series across the mains (forming a potential divider) and the starter is in parallel with the tube on the other side of the filaments. The starter is a voltage / current sensitive device so it *could* be falsely triggered if 1) the voltage goes above it's trigger voltage [1] and / or 2) the starter is made such that it's over sensitive (to voltage)? I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. Cheers, T i m [1] Where the gas (Argon / Neon) in the starter switch capsule get's hot enough to heat the bi-metallic switch and close the contacts. |
#6
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Fluorescent light and starter question.
T i m wrote:
I ordered a cotchel of 4-80W basic starters From Collins Dictionary: "cotchel New Word Suggestion: A large meal or large portion of food. Additional Information possibly from the days of Covent garden fruit market when left over fruit was taken home by workers - eg. taking home a cotchel of fruit." Are your lights eating starters? -- TOJ. |
#7
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Fluorescent light and starter question.
T i m wrote:
I ordered a cotchel of 4-80W basic starters From Collins Dictionary: "cotchel New Word Suggestion: A large meal or large portion of food. Additional Information possibly from the days of Covent garden fruit market when left over fruit was taken home by workers - eg. taking home a cotchel of fruit." Are your lights eating starters? A tranche of starters? -- Graham. %Profound_observation% |
#8
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Fluorescent light and starter question.
On Fri, 20 Apr 2018 22:04:11 GMT, The Other John
wrote: T i m wrote: I ordered a cotchel of 4-80W basic starters From Collins Dictionary: "cotchel New Word Suggestion: A large meal or large portion of food. Additional Information possibly from the days of Covent garden fruit market when left over fruit was taken home by workers - eg. taking home a cotchel of fruit." I'd go more with: https://www.thefreedictionary.com/Cotchel 'a small quantity'. ;-) Are your lights eating starters? If they are they aren't having currents for pudding. ;-) Cheers, T i m |
#10
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Fluorescent light and starter question.
On Saturday, 21 April 2018 07:35:03 UTC+10, T i m wrote:
On Fri, 20 Apr 2018 21:55:35 +0100, ARW wrote: snip The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. snip Voltage drop to the house? Well, that's the sort of thing I am open to but if I understand it right, the ballast and tube are in series across the mains (forming a potential divider) and the starter is in parallel with the tube on the other side of the filaments. The starter is a voltage / current sensitive device so it *could* be falsely triggered if 1) the voltage goes above it's trigger voltage [1] and / or 2) the starter is made such that it's over sensitive (to voltage)? I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. Cheers, T i m [1] Where the gas (Argon / Neon) in the starter switch capsule get's hot enough to heat the bi-metallic switch and close the contacts. I would suspect things around choke. Clean and reconnect the terminals. Sometimes cobweb or cockroach muck could cause change in voltage across the choke. As a total unit, once the plasma is struck the total energy is sum of choke drop and the plasma drop. Plasma energy is generally low, hence choke is the component taking most enrgy. Choke may develope intermittency due to failing insulation.failing insulation. |
#11
Posted to uk.d-i-y
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Fluorescent light and starter question.
On 20/04/2018 22:34, T i m wrote:
I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. Just had a look on the van (I keep starters). Well the first one I picked up was rated 4-65W and 80W! -- Adam |
#12
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Fluorescent light and starter question.
Obviously, but that is hardly an answer to the problem but might help you
keep fit if you like step exercises! The fact that the voltage is still enough to operate the starter still points to the spec being incorrect for the job. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please! "ARW" wrote in message ... On 20/04/2018 18:51, T i m wrote: Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. The starter is a one shot process. Once the tube is lit it has no further use. -- Adam |
#13
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Fluorescent light and starter question.
I wouldn't fanny about like that. Buy an led tube with dummy starter and forget the flickering.
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#14
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Fluorescent light and starter question.
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#15
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 08:32:33 +0100, "Brian Gaff"
wrote: Obviously, but that is hardly an answer to the problem but might help you keep fit if you like step exercises! Quite. The fact that the voltage is still enough to operate the starter still points to the spec being incorrect for the job. I agree Brian. I believe the spec (4-80W) should be good for my 70W tubes so it could just be that they are weak units. It was suggested that along with the gas used in the starter capsule, the initial distance between the electrodes can also set the strike voltage? Cheers, T i m |
#16
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 08:31:30 +0100, ARW
wrote: On 20/04/2018 22:34, T i m wrote: I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. Just had a look on the van (I keep starters). I thought you might (and thanks for looking). ;-) Well the first one I picked up was rated 4-65W and 80W! Oooerr! No use for my 70W tubes then. ;-( Cheers, T i m |
#17
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Fluorescent light and starter question.
In article ,
T i m writes: On Fri, 20 Apr 2018 21:55:35 +0100, ARW wrote: snip The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. snip Voltage drop to the house? Well, that's the sort of thing I am open to but if I understand it right, the ballast and tube are in series across the mains (forming a potential divider) and the starter is in parallel with the tube on the It's not really a potential divider because the tube is far from a resistor. To a first approximation, it's a constant voltage device, and to a second approximation, the voltage across it varies inversely with the current flow. So a reduction in mains voltage will drop the voltage across the inductor, which will drop the current in the circuit, and the second order approximation will raise the tube voltage because of the lower current. This could trigger a marginal starter. other side of the filaments. The starter is a voltage / current sensitive device so it *could* be falsely triggered if 1) the voltage goes above it's trigger voltage [1] and / or 2) the starter is made such that it's over sensitive (to voltage)? I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? Tubes changed their ratings, whereas starters didn't. The 4-80W starters were originally for tubes up to 5'. 5' tubes dropped from 80W to 65W to 58W over time. 6' tubes dropped from 85W to 70W, with the 70W tube having a higher tube voltage than the original 85W tube (so it runs at 70W on original 85W ballasts). So a starter for an old 80W tube might not work on a current 70W tube. It would have been more accurate to rate them by tube length where the original 4-80W starter would have been tubes up to 5', although even that's not perfect. There was generally enough leaway they worked outside their ratings, but you hit one that doesn't. I notice that starters nowadays seem to be 4-65W (which is probably exactly the same as the old 4-80W starter), 70W is a separate starter, also a 70-100W starter (which is probably exactly same as old 125W starter for old 8' tubes). I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. I would look for a 70W starter or 70-100W starter. Cheers, T i m [1] Where the gas (Argon / Neon) in the starter switch capsule get's hot enough to heat the bi-metallic switch and close the contacts. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
#18
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 08:30:32 +0100, "Brian Gaff"
wrote: The spread of tolerances in the starters is far too wide I think. That could be more the case with these 4-80W jobbies than the 70-125W version. Either that or they are marked incorrectly for the job you put them to and all kinds of random changes will then cause issues. I think is the right answer. Probably knock offs made in a Chinese dodgy plant. And you could be right with that as well as they were less than a pound each, delivered (from the UK though). Cheers, T i m |
#19
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Fluorescent light and starter question.
On Friday, 20 April 2018 18:51:25 UTC+1, T i m wrote:
Hi all, So, I have a couple of 6' single TL-D 70W tube fittings in the kitchen and the other day one started flickering. I had a box of new tubes so replaced them both (they were due anyway) but one still wasn't right. I found a spare starter and replaced the iffy one and all was well. The resistance between the filiments is near infinity when "Off" and near zero when the tube is running. This the basic problem. The "choke"/inductors provide the high voltage jolt to establish the "arc" between the filiments and then limits the current when running (hence "choke"). Chokes are very reliable. If it goes wrong, you'll probably be able to smell it. (They can also go open circuit) As someone else has said switch the thing on and remove the starter and observe. If it starts to flicker, the tube is at fault (may take some time). Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) The common fault is for air to leak in. The other fault is for a filiment in the tube to go open circuit. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. |
#21
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 01:10:10 -0700 (PDT), harry
wrote: On Friday, 20 April 2018 18:51:25 UTC+1, T i m wrote: Hi all, So, I have a couple of 6' single TL-D 70W tube fittings in the kitchen and the other day one started flickering. I had a box of new tubes so replaced them both (they were due anyway) but one still wasn't right. I found a spare starter and replaced the iffy one and all was well. The resistance between the filiments is near infinity when "Off" and near zero when the tube is running. Check. This the basic problem. Problem? The "choke"/inductors provide the high voltage jolt to establish the "arc" between the filiments and then limits the current when running (hence "choke"). Understood. Chokes are very reliable. If it goes wrong, you'll probably be able to smell it. (They can also go open circuit) Check. As someone else has said switch the thing on and remove the starter and observe. If it starts to flicker, the tube is at fault (may take some time). Nope, everything solid with the starter out (and that was my first action when the Mrs reported the kitchen light flashing and needed a 'quick fix'). Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) Check. Argon or Neon (and possibly others) in the starter I understand? The common fault is for air to leak in. Oh? The other fault is for a filiment in the tube to go open circuit. Ok. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Hmm. If I had to change these then I'd look at LED but I'm yet to be convinced that it would be worth (electricity savings over outlay) or be able to fully equal the light range of fluorescent tubes? A mate swapped 4 x 6' fluorescent (and fairly old even) tubes in his shop with the brightest LED replacements he could afford but it was noticeably darker in there (but at least he didn't get the migraines). Maybe things have improved since then (~1 year ago)? Cheers, T i m |
#22
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Fluorescent light and starter question.
On Friday, 20 April 2018 21:25:10 UTC+1, T i m wrote:
On Fri, 20 Apr 2018 21:04:20 +0100, ARW wrote: On 20/04/2018 18:51, T i m wrote: Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. It works fine till you turn it off again. ;-) The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. Cheers, T i m [1] The diffusers yellowed and the end plastics went brittle so I may have bought new (slimline) fittings (Fitzgerald?) somewhere along the line. the starter is faulty. It should never interfere once the tube is lit, at least after the first 2 seconds or so. Unless the tube is absolutely on its last legs, which you'd see by increasinly severe flicker every so often then the starter kicks in. Then it runs ok for a bit then goes into flicker again. NT |
#23
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Fluorescent light and starter question.
On Friday, 20 April 2018 22:35:03 UTC+1, T i m wrote:
On Fri, 20 Apr 2018 21:55:35 +0100, ARW wrote: snip The starter is a one shot process. Agreed, it *should* be but I was wondering under what criteria it might try to kick in again after say a couple of hours? eg, what if a ballast was going or a tube etc (except the ballasts have been there since I fitted the units possibly 30 years ago (could be less [1]) and they currently have new Philips tubes). Once the tube is lit it has no further use. Agreed. snip Voltage drop to the house? Well, that's the sort of thing I am open to but if I understand it right, the ballast and tube are in series across the mains (forming a potential divider) and the starter is in parallel with the tube on the other side of the filaments. The starter is a voltage / current sensitive device so it *could* be falsely triggered if 1) the voltage goes above it's trigger voltage [1] and / or 2) the starter is made such that it's over sensitive (to voltage)? no. There's far too much margin for that. I know the bottom line is that the electronic (and old Philips 70-125W) starters work, just that the new 4-80W ones don't (or not fully). Would you use / have you successfully used 4-80W starters on 70W tubes do you know / remember please Adam? I think I'll try to pick up some branded (Philips?) 4-80W starters and see if they work reliably in my lamps. Cheers, T i m [1] Where the gas (Argon / Neon) in the starter switch capsule get's hot enough to heat the bi-metallic switch and close the contacts. |
#24
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Fluorescent light and starter question.
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#25
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Fluorescent light and starter question.
In article ,
harry writes: Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) The common fault is for air to leak in. The other fault is for a filiment in the tube to go open circuit. The three most common failure modes for tubes at end of life a 1) Loss of the electron emission coating on the filament. This was pretty much the only failure mode in all tubes until about about 10 years ago. With switch-start control gear, it shows as a blackened tube end which only glows orange and not white as the starter repeatedly tries and fails to start the tube. No white is because the filament is not emitting electrons when heated red-hot (no thermionic emission), so there's no conduction into the gas-fill, and the discharge can't start. Electronic control gear detects this by seeing the tube start to act as a rectifier and shuts down the tube to prevent it changing to operate as a cold-cathode tube which has a number of dangers. 2) Run out of mercury in the gas. Environmental regulations now require minimum mercury dosing of tubes for the expected life (typically 1/10th of what older T12 tubes used). Mercury is slowly absorbed into the electrodes and glass and lost from the gas fill. This causes tubes to dim with age, and eventually to run a dim pink when all the mercury has gone. 3) Phosphor worn out. Tubes last much longer than they did and the phosphor efficiency drop causes them to dim and become unviable. Air doesn't leak into tubes, even ones which are very many decades old. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Not any more. If you take into account losses in the fluorescent luminare (getting the light from the wrong side of the tube to where you want it, or losing it), they never were. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
#26
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 11:35:12 -0000 (UTC),
(Andrew Gabriel) wrote: In article , harry writes: snip A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Not any more. If you take into account losses in the fluorescent luminare (getting the light from the wrong side of the tube to where you want it, or losing it), they never were. But isn't that often part of the whole 'lighting' process, especially in a domestic environment, having light shining in all directions (especially reflecting off the fitting / ceiling) and giving a much more overall (albeit less efficient) illumination to that space? Working in a room with a single central light reminds me how nice it is to have a 'long' light source, when you start to try to work with a single point and are often in your own shadow. ;-( Are you aware of any 6' LED fittings that offer the same light level and colour temp as the two TL-D 70W 840's I have now? https://www.lampshoponline.com/phili...d-70w-840.html That's not even considering the chances of recovering the cost over the years I have left. ;-( Cheers, T i m |
#27
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Fluorescent light and starter question.
On Saturday, 21 April 2018 12:35:14 UTC+1, Andrew Gabriel wrote:
In article , harry writes: Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) The common fault is for air to leak in. The other fault is for a filiment in the tube to go open circuit. The three most common failure modes for tubes at end of life a 1) Loss of the electron emission coating on the filament. This was pretty much the only failure mode in all tubes until about about 10 years ago. With switch-start control gear, it shows as a blackened tube end which only glows orange and not white as the starter repeatedly tries and fails to start the tube. No white is because the filament is not emitting electrons when heated red-hot (no thermionic emission), so there's no conduction into the gas-fill, and the discharge can't start. Electronic control gear detects this by seeing the tube start to act as a rectifier and shuts down the tube to prevent it changing to operate as a cold-cathode tube which has a number of dangers. 2) Run out of mercury in the gas. Environmental regulations now require minimum mercury dosing of tubes for the expected life (typically 1/10th of what older T12 tubes used). Mercury is slowly absorbed into the electrodes and glass and lost from the gas fill. This causes tubes to dim with age, and eventually to run a dim pink when all the mercury has gone. 3) Phosphor worn out. Tubes last much longer than they did and the phosphor efficiency drop causes them to dim and become unviable. Air doesn't leak into tubes, even ones which are very many decades old. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Not any more. If you take into account losses in the fluorescent luminare (getting the light from the wrong side of the tube to where you want it, or losing it), they never were. FWIW there are thinner ones with better efficacy than T8 or T12 but their ouput v temp dependance is horrible NT |
#28
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Fluorescent light and starter question.
On 21/04/2018 08:33, Cynic wrote:
I wouldn't fanny about like that. Buy an led tube with dummy starter and forget the flickering. +1 -- Adam |
#29
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Fluorescent light and starter question.
On 21/04/2018 12:35, Andrew Gabriel wrote:
In article , harry writes: Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) The common fault is for air to leak in. The other fault is for a filiment in the tube to go open circuit. The three most common failure modes for tubes at end of life a 1) Loss of the electron emission coating on the filament. This was pretty much the only failure mode in all tubes until about about 10 years ago. With switch-start control gear, it shows as a blackened tube end which only glows orange and not white as the starter repeatedly tries and fails to start the tube. No white is because the filament is not emitting electrons when heated red-hot (no thermionic emission), so there's no conduction into the gas-fill, and the discharge can't start. Electronic control gear detects this by seeing the tube start to act as a rectifier and shuts down the tube to prevent it changing to operate as a cold-cathode tube which has a number of dangers. 2) Run out of mercury in the gas. Environmental regulations now require minimum mercury dosing of tubes for the expected life (typically 1/10th of what older T12 tubes used). Mercury is slowly absorbed into the electrodes and glass and lost from the gas fill. This causes tubes to dim with age, and eventually to run a dim pink when all the mercury has gone. 3) Phosphor worn out. Tubes last much longer than they did and the phosphor efficiency drop causes them to dim and become unviable. Air doesn't leak into tubes, even ones which are very many decades old. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Not any more. If you take into account losses in the fluorescent luminare (getting the light from the wrong side of the tube to where you want it, or losing it), they never were. Yes but that only goes to show that is you do the opposite of what harry says then there is a good chance you are correct. -- Adam |
#30
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 15:26:23 +0100, ARW
wrote: On 21/04/2018 08:33, Cynic wrote: I wouldn't fanny about like that. Buy an led tube with dummy starter and forget the flickering. +1 Or just buy electronic starters and get the same result. ;-) Cheers, T i m |
#31
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Fluorescent light and starter question.
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#32
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Fluorescent light and starter question.
On Fri, 20 Apr 2018 21:04:20 +0100, ARW wrote:
On 20/04/2018 18:51, T i m wrote: Now, What *I* think might be happening (on the first two new starters at least) is they initially start and run the tubes (two separate fittings) ok until everything warms up, when the voltage across the tube increases slightly, causing the starter to re-trigger and the tube to blink off and back on again. This process is fairly repeatable (it might vary between fittings) and the blinking get's worse if left. Is it just duff (weak) starters or *could there* be something else? Remove the starter after the tube is lit and see what happens. The starter is a one shot process. Once the tube is lit it has no further use. Until the time you need to switch the light back on again. :-( I've had the same sort of trouble with the last remaining fluorescent fitting that I couldn't upgrade to a "Quickstart"(tm) transformer ballast on account I couldn't get the older style compatible T12 tubes for this 5 foot fitting[1]. The problem is clearly down to ****e quality starter switches and I eventually sorted it out by buying enough of them from which to choose a working one (about 4 or so 'new' ones to add to my existing collection of two or three). Even so, it takes some 5 to 10 seconds before the tube will strike, strangely, sans the disco strobe effect - it just sits there with the ends glowing (or not) before suddenly striking to full uninterrupted brightness. As a consequence, it tends to be left switched on for the whole evening. [1] One of these days, when we finally start seeing 200LPW LED equivalents to the 150W incandescent GLS light bulb, I'll revert it back to the ceiling pendant fitting it had before this 'spare bedroom' became my office/workshop some 20 years ago. The unavailability of Quickstart compatible tubes hit home over a decade ago with the shorter 4 foot variety so the last remaining 4 foot Quickstart fitting (in the basement) is now relying on the very last working compatible tube until it too finally expires (they last a bloody sight longer in Quickstart fittings - 16000 hours versus 7000 hours or so in a switch start fitting). Fluorescent luminaires are the only sane choice in some locations such as kitchens (and my basement) for their non-glare, shadowless illumination properties. Until recently, they were still top dog for energy efficient lighting (still are compared to the older stock of LED Tubes being foisted on the great unwashed consumer in most retail stores). However, once I start to see 125LPW (or better) 300 to 360 deg LED tube replacements, I'll upgrade the last of my fluorescent fittings. Until then, I don't see much point in wasting time and money on a mediocre 'upgrade'. Alternatively, large area ceiling panel luminaires might make a more suitable substitute for the humble fluorescent tube fitting. At the end of the day, it all boils down to their cost effectiveness. -- Johnny B Good |
#33
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 15:26:23 +0100, ARW wrote:
On 21/04/2018 08:33, Cynic wrote: I wouldn't fanny about like that. Buy an led tube with dummy starter and forget the flickering. +1 -10 ! Unless you buy from a lighting specialist that can supply the latest 120LPW LED tube substitutes, you might be better off upgrading to a microprocessor controlled electronic ballast. I was considering an LED tube upgrade for our 4 foot 36W cheap electronically ballasted B&Q fitting bought about two years ago now, when the 2nd tube in 18 months (replacement to the original, presumed low quality tube) started to give trouble. Switching the tube, end over end in the fitting gave less than a week's relief from the starting failure, culminating in the fitting 'going quietly Pop!'. I wasn't impressed with either alternative of new ballast or a complete re-lamp with the unimpressively inefficient and over-priced LED tube options. However, persistence paid off and I bought a high quality Helvar ballast for just under a fiver delivered postage free[1]. At that price, it was the no brainer choice of repair. However, the second tube had been so shagged by the Chinese ballast, the Helvar ballast refused to even try starting it. I had slightly better luck with the original but only in that it would light it up briefly before aborting further starting attempts (fussy microprocessor controller - I assumed). My assumption proved to be correct but I did have to chance buying yet another tube, from Toolstation this time rather than my local lighting specialist from whom I'd bought the last one. In fact, I landed up buying yet another, cool white this time rather than warm white - I'd forgotten to take account of the kitchen's pale yellow colour scheme. At least I have a working spare, even if it is a little on the warm side for the kitchen's current colour scheme. [1] https://www.amazon.co.uk/Helvar-EL1x...le-Electronic- Ballast/dp/B07217Q8FF/ref=sr_1_5? s=lighting&ie=UTF8&qid=1524354946&sr=1-5&keywords=helvar+ballast Would seem to be the very same item but a penny cheaper! :-) If your fluorescent light fitting is a single 36W T8 tubed 4 foot luminaire, that should suit your needs nicely. It doesn't strike the modern T8 tubes as slickly as the ancient but very effective Quickstart ballasts did with the original T12 compatible tubes (250ms versus 900ms of the modern life enhancing microprocessor controlled electronic high frequency ballasts) but that's the price paid for a reduction from 52W consumption down to the 36W exactly of an electronically ballasted 4 foot T8 tube (I'd measured exactly 36W with both ballasts). -- Johnny B Good |
#34
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 11:35:12 +0000, Andrew Gabriel wrote:
In article , harry writes: Both tube and starter have sub-atmospheric gas filled glass bulbs. (Plus mercury in the tube) The common fault is for air to leak in. The other fault is for a filiment in the tube to go open circuit. The three most common failure modes for tubes at end of life a 1) Loss of the electron emission coating on the filament. This was pretty much the only failure mode in all tubes until about about 10 years ago. With switch-start control gear, it shows as a blackened tube end which only glows orange and not white as the starter repeatedly tries and fails to start the tube. No white is because the filament is not emitting electrons when heated red-hot (no thermionic emission), so there's no conduction into the gas-fill, and the discharge can't start. Electronic control gear detects this by seeing the tube start to act as a rectifier and shuts down the tube to prevent it changing to operate as a cold-cathode tube which has a number of dangers. This was an issue aggravated by the use of cheap bi-pin switch started lamps in domestic service (kitchens, basements, sheds and the circular tubes used in hallways and landings). Each switch start attempt would sputter some of the thoriated coating off the cathodes/cum anodes, shortening the service life when used in such frequently switched applications. The older (half century older!) Quickstart transformer technology not only gave an almost instant flicker free startup (200 to 300ms) but significantly reduced this sputtering effect which could double or even triple the service life of a tube used in a domestic kitchen over that using the cheap bi-pin switch start circuit, especially useful since it encouraged the occupiers to treat it as an instant start incandescent (but with a service life around an order of magnitude longer). 2) Run out of mercury in the gas. Environmental regulations now require minimum mercury dosing of tubes for the expected life (typically 1/10th of what older T12 tubes used). Mercury is slowly absorbed into the electrodes and glass and lost from the gas fill. This causes tubes to dim with age, and eventually to run a dim pink when all the mercury has gone. I lament the parsimonious mercury dosing of modern T8 lamps since it lends an unwanted "run up" characteristic, especially noticeable in the winter months, more associated with the mercury amalgam variants used in CFLs. The earlier fully dosed T12 tubes only showed the slightest hint of this with really low temperatures not usually seen in a domestic environment even in the winter other than for outhouse lighting. In regard of both startup and run up time, modern electronically ballasted fluorescent luminaires(sp?) have taken a backwards step over the ancient Quickstart fittings. I guess that's the price you pay to save some 16 watt's of consumption on a 4 foot fluorescent fitting. 3) Phosphor worn out. Tubes last much longer than they did and the phosphor efficiency drop causes them to dim and become unviable. Air doesn't leak into tubes, even ones which are very many decades old. True enough, the phosphors have to deal with mercury poisoning as well as the degradation from UV radiation - the phosphor coating on LEDs doesn't have to contend with this so they last a lot longer (but nevertheless still slowly degrade over time). In office and factory environments, fluorescent lamps were replaced en masse after clocking up the rated hours for the 80% of design lumens point, thousands of hours before the more gross and obvious failures would start showing other than for defectively manufactured lamps. This was simply because changing out lamps by the gross was far cheaper both in electricity consumption to meet the minimum lighting standard required by regulations and the labour costs involved in relamping on an ad hoc basis as each individual lamp failed to produce its design lumens output one way or another. A fluorescent tube with electronic "choke" is as efficient as an LED bulb. Not any more. For the general public, that's a fairly recent development, I first saw 125LPW samples just over a year ago and I think prior to that, most of the retail outlets were (and still are) offering 81 or 90 LPW lamps. You can still see plenty of 60LPW lamps in the smaller wattages on sale even today (about the same efficiency as the best CFLs of recent years). The best efficiency tubes maxed out around the 90 to 100LPW mark. If you take into account losses in the fluorescent luminare (getting the light from the wrong side of the tube to where you want it, or losing it), they never were. For situations where a nice diffuse, shadowless lighting effect is desired, such as a kitchen or a shed come DIY workshop or a low ceilinged basement, that's not quite the deficiency it would seem. However, these days when such a lighting characteristic is deemed desirable, a better solution would be the use of ceiling mounted LED flat panels with a suitable diffusing cover to mute the horrendous glare typical of naked LEDs. -- Johnny B Good |
#35
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Fluorescent light and starter question.
On Saturday, April 21, 2018 at 5:43:15 PM UTC+10, T i m wrote:
On Sat, 21 Apr 2018 00:31:21 -0700 (PDT), wrote: snip I would suspect things around choke. Clean and reconnect the terminals. Sometimes cobweb or cockroach muck could cause change in voltage across the choke. I did have a look in one of the two units (that are behaving similarly) and it was as clean in there as when I installed it from new (you don't live in a seedy restaurant in Thailand do you)? ;-) As a total unit, once the plasma is struck the total energy is sum of choke drop and the plasma drop. Plasma energy is generally low, hence choke is the component taking most enrgy. Choke may develope intermittency due to failing insulation.failing insulation. That would have to be on two independent units then? Not impossible of course but at the same time after maybe 20 years? Cheers, T i m Just to make it clear to you- the plasma breaks due to high voltage induced due to choke in series with the starter which breaks the circuit to cause it; before plasma breaks tube a high resitance in series with the choke. For your info I am not in Thailand or some stinking Thames river country, I am in Australia a clean intelligent country where early convict arrivals have long been dead! |
#36
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Fluorescent light and starter question.
On Sat, 21 Apr 2018 22:41:11 -0700 (PDT),
wrote: On Saturday, April 21, 2018 at 5:43:15 PM UTC+10, T i m wrote: On Sat, 21 Apr 2018 00:31:21 -0700 (PDT), wrote: snip I would suspect things around choke. Clean and reconnect the terminals. Sometimes cobweb or cockroach muck could cause change in voltage across the choke. I did have a look in one of the two units (that are behaving similarly) and it was as clean in there as when I installed it from new (you don't live in a seedy restaurant in Thailand do you)? ;-) As a total unit, once the plasma is struck the total energy is sum of choke drop and the plasma drop. Plasma energy is generally low, hence choke is the component taking most enrgy. Choke may develope intermittency due to failing insulation.failing insulation. That would have to be on two independent units then? Not impossible of course but at the same time after maybe 20 years? Cheers, T i m Just to make it clear to you- Ok ... the plasma breaks due to high voltage induced due to choke in series with the starter which breaks the circuit to cause it; before plasma breaks tube a high resitance in series with the choke. Ok? For your info I am not in Thailand or some stinking Thames river country, So no roaches there either then? I am in Australia a clean intelligent country where early convict arrivals have long been dead! Ah, hence the thought re spiders living in your lights, interfering with the inductance. ;-) Cheers, T i m |
#37
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Fluorescent light and starter question.
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#38
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Fluorescent light and starter question.
On Sunday, 22 April 2018 00:23:26 UTC+1, Johnny B Good wrote:
On Fri, 20 Apr 2018 21:04:20 +0100, ARW wrote: Remove the starter after the tube is lit and see what happens. The starter is a one shot process. Once the tube is lit it has no further use. Until the time you need to switch the light back on again. :-( I think anyone with a working brain would put it back don't you? Even without it thought one can still fire a light up. Just arc the switch. NT |
#39
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Fluorescent light and starter question.
On Sunday, April 22, 2018 at 5:35:35 PM UTC+10, T i m wrote:
On Sat, 21 Apr 2018 22:41:11 -0700 (PDT), wrote: On Saturday, April 21, 2018 at 5:43:15 PM UTC+10, T i m wrote: On Sat, 21 Apr 2018 00:31:21 -0700 (PDT), wrote: snip I would suspect things around choke. Clean and reconnect the terminals. Sometimes cobweb or cockroach muck could cause change in voltage across the choke. I did have a look in one of the two units (that are behaving similarly) and it was as clean in there as when I installed it from new (you don't live in a seedy restaurant in Thailand do you)? ;-) As a total unit, once the plasma is struck the total energy is sum of choke drop and the plasma drop. Plasma energy is generally low, hence choke is the component taking most enrgy. Choke may develope intermittency due to failing insulation.failing insulation. That would have to be on two independent units then? Not impossible of course but at the same time after maybe 20 years? Cheers, T i m Just to make it clear to you- Ok ... the plasma breaks due to high voltage induced due to choke in series with the starter which breaks the circuit to cause it; before plasma breaks tube a high resitance in series with the choke. Ok? For your info I am not in Thailand or some stinking Thames river country, So no roaches there either then? I am in Australia a clean intelligent country where early convict arrivals have long been dead! Ah, hence the thought re spiders living in your lights, interfering with the inductance. ;-) Cheers, T i m Ah, hence the thought re spiders living in your lights, interfering with the inductance. ;-) Matey! one can survive with spider stings but has no such chance with plague from rats in Thames bank;-) |
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