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Old March 4th 19, 11:19 AM posted to uk.d-i-y
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On Friday, 1 March 2019 19:35:02 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
This lab was build in the 1960s last electrical refurbishment was in the
mid 90s. But still never seen any dimmable florescant in the dept or
uni, there must be a reason.


Generally, florries in a lab are working lights. Why would you need to dim
them?


Because that's what the designers of the new lab said we need, you don't think they'll ask us users do you ?
I didnlt think we needed auto on lights in teh toilets either, or the taps which use PIR , which means yuo canlt adjust teh water temperature for yourself up or down or the lifts where you have to tell it what floor before you get in it and then wait for the lift that goes to that floor.
I wouldn't have spent the thousands on the smart AV lecture tables either.


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Old March 4th 19, 11:28 AM posted to uk.d-i-y
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On Friday, 1 March 2019 19:35:02 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
On Friday, 1 March 2019 14:31:48 UTC, Dave Plowman (News) wrote:
In article ,
Brian Gaff wrote:
Could one ask why you would want to these days, assuming you could find
any to install!

Is it that far behind LEDs etc in terms of efficiency/life?


I've heard they are, but not having testd them myself I can't say.



A florry gives a more even illumination than a series of LEDs.


That's not really true espeacily over time, the ends of florrys go black
and start to flicker and get dimmer with time.


With old fashioned ballasts, possibly. But high frequency ones have been
around for many years now. The light output does go down slightly with
age, though.


All I know is the lighting was replaced in the mid 90s. with new florries.
All teh electrics of the lab were redone.




Also a better selection of colour temperature, etc.


Not sure that is true, but it should be difficult for LED tubes to be desined like the phillips hues.


Many might prefer to have the colour temperature they want from the off
without messing about.


And far more don;t get the choice we haven't the choice.
When the florries go dim or start flashing we call maintaince (we wait until a few are on the blink) and within the month they come over and change them.



We have new LED tubes in our new lab auto on and off, in my office they
are also dimmable unlike the florrys in my present office, one of which
is just flickering. One in the corridor is flickering and making a
noise. It could wake the students up ;-)


Dimming florries with electronic ballasts has also been around for many a
year. The ones lighting my kitchen worktops - installed some 20 years ago.


But we didn't have them installed here, I doubt we considered we had a need for dimmable, I didn't think we needed them, but it;s not like we were asked.
All we wanted was better lighting than the 1980s lighting we had.

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Old March 4th 19, 11:31 AM posted to uk.d-i-y
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On Friday, 1 March 2019 19:35:03 UTC, Dave Plowman (News) wrote:
In article ,
NY wrote:
"whisky-dave" wrote in message
...


Dimmable fluorescent fittings have been around since the early 1960s.
Nothing new there.


How are fluorescents dimmed? I'd always thought that it was impossible,
and was surprised when the fluorescents in my school lecture theatre
could be dimmed. They were probably installed in the early to mid 70s,
which gives an idea of what technology was available then. I remember a
huge cabinet about the size of a 6-foot high freezer in the projection
unit which gave off a hell of a hum as the lights were going from full
off to full on, which they did on a timer: the lecturer pressed a
button and they dimmed/brightened automatically over the course of
about 5 seconds.


With the electronic ballasts I have here, all you need to add is a simple
pot to dim them.


Good for yuo all we have is 2 panels with 8 rocker switches on each to control the lights, not sure I could have replaced those 'rockers' with 16 pots just like that.

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Old March 4th 19, 11:43 AM posted to uk.d-i-y
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On Monday, 4 March 2019 11:31:20 UTC, whisky-dave wrote:
On Friday, 1 March 2019 19:35:03 UTC, Dave Plowman (News) wrote:
In article ,
NY wrote:
"whisky-dave" wrote in message
...


Dimmable fluorescent fittings have been around since the early 1960s.
Nothing new there.


How are fluorescents dimmed? I'd always thought that it was impossible,
and was surprised when the fluorescents in my school lecture theatre
could be dimmed. They were probably installed in the early to mid 70s,
which gives an idea of what technology was available then. I remember a
huge cabinet about the size of a 6-foot high freezer in the projection
unit which gave off a hell of a hum as the lights were going from full
off to full on, which they did on a timer: the lecturer pressed a
button and they dimmed/brightened automatically over the course of
about 5 seconds.


With the electronic ballasts I have here, all you need to add is a simple
pot to dim them.


Good for yuo all we have is 2 panels with 8 rocker switches on each to control the lights, not sure I could have replaced those 'rockers' with 16 pots just like that.


If they're the old type that flash during starting, just loosen the starter on a fitting & it doesn't start. Easiest way to dim the room.

Why dim? IME nearly all commercial & school fluorescent installs are heavily overpowered.


NT
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Old March 4th 19, 11:47 AM posted to uk.d-i-y
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On Friday, 1 March 2019 19:48:36 UTC, Andrew Gabriel wrote:
On 01/03/2019 16:30, whisky-dave wrote:
On Friday, 1 March 2019 16:02:52 UTC, NY wrote:
"whisky-dave" wrote in message
...

Dimmable fluorescent fittings have been around since the early 1960s..
Nothing new there.

How are fluorescents dimmed?


I waqsnt; sure so looked it up.

https://www.etcconnect.com/Support/A...ures-Work.aspx

I'd always thought that it was impossible,


well I knew it was possible but a bit more difficult than just replacing a light switch with a dimmer switch.


It is basically replacing the light switch with a dimmer (suitable for
inductive loads), but you also need to add a separate pair of isolated
supplies to keep the filaments hot enough to continue operating in
thermionic emission mode when the tube current is too low to do it just
by itself. This will also enable the tube to strike without a starter.

Indeed, I made just such a light as a teenager.


I'm not allowed to just replace the lighting in a teaching lab with something I did at home. I also have about 45 double tubes in the lab.



Commercially, Transtar was a well known manufacturer of dimming magnetic
ballasts (and very high quality non-dimming ballasts).


Good for them but I leave that to those designing the spaces in the lab.

Just has a academic asking for a 96V or higher PSU I politely laughed.

I've been asked to suggest the purchase of some new bench supplies for the lab but I doubt I'll get permission to order ones that got up 96V.
I'm not looking at anything about 30V at the moment.





and
was surprised when the fluorescents in my school lecture theatre could be
dimmed. They were probably installed in the early to mid 70s, which gives an
idea of what technology was available then.


One issue with banks of dimming fluorescents is all the tubes had to be
replaced together, otherwise newer and older tubes are significantly
different light output, and different makes can be different too.


Yes we have that problem witout dimmering, 3 faulty in the lab at the moment with 1 or 2 on their last legs.


Also, you get colour shift and a significant drop in CRI when dimming
fluorescents, as the ratio of light output from the different mercury
line changes, which upsets the colour balance from the arc and the
phosphor (tend to lose more green and end up with purple from the over
balance of red and blue).


Makes me think that perhaps LED tubes are better. We did ask for them rather than florries but the cost would have be over £3k so was rejected.



Nowadays with microcontroller based electronic ballasts, adding dimming
is trivial, although it's not done by using triac dimmers. 0-10V, DALI,
switch-dim, or photocell to generate constant lux level are common, and
many electronic ballasts support multiple of these.


why not use LEDs ?


Indeed, many electronic ballasts support multiple different tubes that
run at different currents, and having identified the tube in use from
the electrical characteristics, effectively use the internal dimmer
logic to limit the current to the max allowed for the identified tube.


I think that's what our new LED tubes in the new lab do, on walking over to them after a few seconds they come on whether wanted on or not.

WHich is going to be fun when they want the light out when using photocells in a lab experiment can't wait to have to explain that one the the 'designers'



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Old March 4th 19, 01:03 PM posted to uk.d-i-y
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On Monday, 4 March 2019 11:43:43 UTC, wrote:
On Monday, 4 March 2019 11:31:20 UTC, whisky-dave wrote:
On Friday, 1 March 2019 19:35:03 UTC, Dave Plowman (News) wrote:
In article ,
NY wrote:
"whisky-dave" wrote in message
...


Dimmable fluorescent fittings have been around since the early 1960s.
Nothing new there.

How are fluorescents dimmed? I'd always thought that it was impossible,
and was surprised when the fluorescents in my school lecture theatre
could be dimmed. They were probably installed in the early to mid 70s,
which gives an idea of what technology was available then. I remember a
huge cabinet about the size of a 6-foot high freezer in the projection
unit which gave off a hell of a hum as the lights were going from full
off to full on, which they did on a timer: the lecturer pressed a
button and they dimmed/brightened automatically over the course of
about 5 seconds.

With the electronic ballasts I have here, all you need to add is a simple
pot to dim them.


Good for yuo all we have is 2 panels with 8 rocker switches on each to control the lights, not sure I could have replaced those 'rockers' with 16 pots just like that.


If they're the old type that flash during starting, just loosen the starter on a fitting & it doesn't start. Easiest way to dim the room.


So I go around with a ladder messing about with upto 20 tube starters not thanks.


Why dim? IME nearly all commercial & school fluorescent installs are heavily overpowered.


When the projection system is being used or they want to show slides or whatever I assume. I don't think we asked for dimmable lights. well it wasn't part of the things I wanted in the lab.






NT


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Old March 4th 19, 02:11 PM posted to uk.d-i-y
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Default Fluorescent lighting

In article ,
whisky-dave wrote:
On Friday, 1 March 2019 19:35:02 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
This lab was build in the 1960s last electrical refurbishment was in
the mid 90s. But still never seen any dimmable florescant in the
dept or uni, there must be a reason.


Generally, florries in a lab are working lights. Why would you need to
dim them?


Because that's what the designers of the new lab said we need, you don't
think they'll ask us users do you ?


I'm really not surprised given your replies to questions on here. ;-)



I didnlt think we needed auto on
lights in teh toilets either, or the taps which use PIR , which means
yuo canlt adjust teh water temperature for yourself up or down or the
lifts where you have to tell it what floor before you get in it and then
wait for the lift that goes to that floor. I wouldn't have spent the
thousands on the smart AV lecture tables either.


--
*Never miss a good chance to shut up *

Dave Plowman London SW
To e-mail, change noise into sound.
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Old March 4th 19, 02:13 PM posted to uk.d-i-y
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Default Fluorescent lighting

In article ,
whisky-dave wrote:
On Friday, 1 March 2019 19:35:03 UTC, Dave Plowman (News) wrote:
In article ,
NY wrote:
"whisky-dave" wrote in message
...


Dimmable fluorescent fittings have been around since the early
1960s. Nothing new there.


How are fluorescents dimmed? I'd always thought that it was
impossible, and was surprised when the fluorescents in my school
lecture theatre could be dimmed. They were probably installed in the
early to mid 70s, which gives an idea of what technology was
available then. I remember a huge cabinet about the size of a 6-foot
high freezer in the projection unit which gave off a hell of a hum
as the lights were going from full off to full on, which they did on
a timer: the lecturer pressed a button and they dimmed/brightened
automatically over the course of about 5 seconds.


With the electronic ballasts I have here, all you need to add is a
simple pot to dim them.


Good for yuo all we have is 2 panels with 8 rocker switches on each to
control the lights, not sure I could have replaced those 'rockers' with
16 pots just like that.


I'm quite sure you couldn't. But this is a DIY group, so many obviously
can.

--
*A plateau is a high form of flattery*

Dave Plowman London SW
To e-mail, change noise into sound.
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Old March 4th 19, 02:15 PM posted to uk.d-i-y
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In article ,
wrote:
Why dim? IME nearly all commercial & school fluorescent installs are heavily overpowered.


Why? The need to dim lights in a domestic setting easy to understand. But
even then why make them more powerful than ever needed?

--
*It is wrong to ever split an infinitive *

Dave Plowman London SW
To e-mail, change noise into sound.
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Old March 4th 19, 04:20 PM posted to uk.d-i-y
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On Monday, 4 March 2019 14:18:21 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
On Friday, 1 March 2019 19:35:02 UTC, Dave Plowman (News) wrote:
In article ,
whisky-dave wrote:
This lab was build in the 1960s last electrical refurbishment was in
the mid 90s. But still never seen any dimmable florescant in the
dept or uni, there must be a reason.

Generally, florries in a lab are working lights. Why would you need to
dim them?


Because that's what the designers of the new lab said we need, you don't
think they'll ask us users do you ?


I'm really not surprised given your replies to questions on here. ;-)


Well I was asked my views, but I never said I wanted auto lights I did say we wanted a section of the lab that could be made dark for visual experiments we had this 30 years ago for opto electronics experiments with lasers.
I wanted a room where students could work on audio projects doesn't need to be completley soundproof. They ahve partly done that with a bit of sound proofing and an extra thick door.

I asked for the lab to be a heated one and have got that with overhead heaters for some reason. I wanted indicidual cupboards for the desks, and got that.
We even have temperature readouts and settable to 0.1C (I believe that once I're tried it)

We didnlt want the expensive AV desks that are about £5k but apparenty that is the default now. We wanted second monototrs for AV as we have them in the old lab. They said we must have the newer 4K ones.
We got to chose the carper and tiles too, the chairs and stools. They tried to get us to buy the expensive chairs that are adjustable at £200+ each we settled for the OK ones of about £45.
We even thought about the opening ceromony and I said we should get Maggie Philbin to open it and they think that's a good idea and looking into it.

Sometimes they listen to me/us other times they don't.


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