Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

wrote:

The lighting is all led controlled using rako rdl250c units:
http://www.rakocontrols.com/products...ne-dimmer.html.

Unfortunately that's exactly the wrong type of dimmer for LEDs, you need
trailing-edge dimmers for most dimmable LEDs (do you know that the LEDs
used are all dimmable?)

Additionally the dimmers need to be able to work *down* to 5W or 10W
whatever your smallest set of LED lamps are, rather than *up* to 250W
for incandescent loads.

Often one tungsten light on the system will sort this issue, but as he says
halogen are doing it, this might be a bluish white herring!

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Andy Burns" wrote in message
o.uk...
wrote:

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

Unfortunately that's exactly the wrong type of dimmer for LEDs, you need
trailing-edge dimmers for most dimmable LEDs (do you know that the LEDs
used are all dimmable?)

Additionally the dimmers need to be able to work *down* to 5W or 10W
whatever your smallest set of LED lamps are, rather than *up* to 250W for
incandescent loads.

wrote:

http://www.rakocontrols.com/products...ne-dimmer.html.

Looking at the spec sheet, the minimum load is 20W. LED downlighters
vary in power, but 2.5 to 4.5W is typical, so depending on yours, you
may have problems if they're controlled in groups of fewer then 5-8
downlighters ....

On Saturday, 1 August 2015 21:03:56 UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

LEDs are less affected than halogen. But trad dimmers and minimal loads don't mix well


NT

On 02/08/2015 00:22, wrote:


LEDs are less affected than halogen. But trad dimmers and minimal
loads don't mix well

The OP could put a couple of halogen lamps in the circuit to see if it
is the load being too small??

dennis@home wrote:
On 02/08/2015 00:22, wrote:


LEDs are less affected than halogen. But trad dimmers and minimal
loads don't mix well

The OP could put a couple of halogen lamps in the circuit to see if it
is the load being too small??

Yeah, paint them black as well.

Bill

On 04/08/2015 02:40, Bill Wright wrote:
dennis@home wrote:
On 02/08/2015 00:22, wrote:


LEDs are less affected than halogen. But trad dimmers and minimal
loads don't mix well

The OP could put a couple of halogen lamps in the circuit to see if it
is the load being too small??

Yeah, paint them black as well.

Bill

Only if they are the dichroic kind and the fitting is heat proof.
You do know that painting plain reflector types is dangerous?
and fitting the dichroic kind is dangerous in some fittings.

On Tuesday, August 4, 2015 at 11:02:49 AM UTC+1, dennis @ home wrote:
On 04/08/2015 02:40, Bill Wright wrote:
dennis@home wrote:
On 02/08/2015 00:22, wrote:


LEDs are less affected than halogen. But trad dimmers and minimal
loads don't mix well

The OP could put a couple of halogen lamps in the circuit to see if it
is the load being too small??

Yeah, paint them black as well.

Bill

Only if they are the dichroic kind and the fitting is heat proof.
You do know that painting plain reflector types is dangerous?
and fitting the dichroic kind is dangerous in some fittings.

Hence suggestion of trying 15W pygmy, easy to hide in a wiring cupboard or ceiling void, sometimes it just needs some resitive load, sometimes a lot of resitive load...

On Saturday, August 1, 2015 at 9:03:56 PM UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

Halogen ripple may be getting superimposed by the dimmers for the LEDs.

Wrong type of dimmer generally for LEDs, but then Rako`s MR16, downlighter lamp, range dosen`t exist:

http://www.rakocontrols.com/products...led-lamps.html

it does in docs though

http://www.rakocontrols.com/files/77...heet_lores.pdf

Some MR16 lamp makers will reccomend trailing edge dimming, even then won`t dim to zero and will usually start at above 10%.

Trailing edge dimmers are expensive and relatively easy to blow up.

Some dimmable lamps are better than others and play nicer with some types of dimmer better.

Rako`s solution of using 12V lamps, dimmable in some form, with a Constant Voltage driver makes more sense.

Your fitter new to LEDs........

To be honest I do not think there would be much you or your electrician
could do other than to take a hand held led light that shows the issue and
ask some of the other flat owners to try it. If only yourself gets the
issue, you would need the leccy folk in, but if its general and you cannot
convince others to complain with you, I doubt the leccy folk will be that
interested.

The effect you mention is not new with dimmers at low levels. Back in the
1970s down muy garden, I could not use a dimmer on an ordinary bulb as it
wobbled in brightness apparently randomly.
Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


wrote in message
...
Hi,

I have had lighting installed in my flat. Although my fitter is still being
helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...immer.html.The problem I have is that there is noticeable changes in light intensitywhich becomes very evident when the leds are dimmed. The best way I candescribe it is that the leds look like candle flames. I don't think it is amains frequency flicker.Now that I look carefully at traditional halogen lamps elsewhere in the flatI can also detect a less pronounced flicker.My guess at what is happening is that I have an unstable voltage supply.Note that block of flats (7 flats in total) does not have a gas supply soall of the heating and cooking is on the electric supply. The leds reactfaster that the halogen lamps so that the intensity changes are moreevident.Any advice or ideas appreciated. The total load of led lights is about 150watts (20 downlighters plus led strips).Mike

On Saturday, 1 August 2015 21:03:56 UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

Many thanks for all the replies. I don't think the minimum load issue is a problem the circuits have 9x5watt, 6x5w and 5x5w on them. I will double check all the part numbers to see if the wrong type of dimmer is part of the problem.

Mike

wrote:

Many thanks for all the replies. I don't think the minimum load
issue is a problem the circuits have 9x5watt, 6x5w and 5x5w on them.
I will double check all the part numbers to see if the wrong type of
dimmer is part of the problem.

Are the downlighters using GU10 lamps? If so, perhaps your installer
could try replacing one of the dimmers with this type to see if it
solves the flickering ...

http://www.rakocontrols.com/products/home/104-500w-in-line-rf-dimmer-for-trailing-edge-dimmable-loads.html

Presumably it will be compatible with whatever form of remote control
you have for the existing dimmers?

Many thanks for all the replies. I don't think the minimum load issue is a problem the circuits have 9x5watt, 6x5w and 5x5w on them. I will double check all the part numbers to see if the wrong type of dimmer is part of the problem.

Mike

Its not a straight resistive load unfortunately, adding a resistive load even a small one may help the dimmers behave better, try a 15w pygmy lamp in paralell.

On 03/08/2015 14:00, Adam Aglionby wrote:


Many thanks for all the replies. I don't think the minimum load
issue is a problem the circuits have 9x5watt, 6x5w and 5x5w on
them. I will double check all the part numbers to see if the wrong
type of dimmer is part of the problem.

Mike

Its not a straight resistive load unfortunately, adding a resistive
load even a small one may help the dimmers behave better, try a 15w
pygmy lamp in paralell.

Agreed.

On Monday, 3 August 2015 12:45:20 UTC+1, wrote:
On Saturday, 1 August 2015 21:03:56 UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply.. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

On 01/08/2015 21:03, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is
still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light
intensity which becomes very evident when the leds are dimmed. The
best way I can describe it is that the leds look like candle flames.
I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in
the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage
supply. Note that block of flats (7 flats in total) does not have a
gas supply so all of the heating and cooking is on the electric
supply. The leds react faster that the halogen lamps so that the
intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is
about 150 watts (20 downlighters plus led strips).


Most traditional/old (leading edge) dimmers are sensitive to mains noise
as they use DIACs as a crude way to time the turn on of the TRAIC or
Thyrister. I've looked at more current circuits, obviously made to a
price, that still use DIACs.

Trailing edge are more complex.

For general info:

http://www.ledjournal.com/main/blogs...-edge-dimmers/

On Monday, August 3, 2015 at 7:07:46 PM UTC+1, Fredxxx wrote:
On 01/08/2015 21:03, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is
still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light
intensity which becomes very evident when the leds are dimmed. The
best way I can describe it is that the leds look like candle flames.
I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in
the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage
supply. Note that block of flats (7 flats in total) does not have a
gas supply so all of the heating and cooking is on the electric
supply. The leds react faster that the halogen lamps so that the
intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is
about 150 watts (20 downlighters plus led strips).


Most traditional/old (leading edge) dimmers are sensitive to mains noise
as they use DIACs as a crude way to time the turn on of the TRAIC or
Thyrister. I've looked at more current circuits, obviously made to a
price, that still use DIACs.

Thats a cheap wall plate dimmer, the Rako`s will use proper zero crossing detection , MPU and opto isolated triac for firing.

Still can get problems with the triac latching even on hard firing dimmers with low loads.


Trailing edge are more complex.

For general info:

http://www.ledjournal.com/main/blogs...-edge-dimmers/

Trailing edge are vulnerable to accidental connection to inductive loads, a wound lighting trafo for instance, acts somewhat like an ignition coil.

Not a fan , still cant get to zero.

On 03/08/2015 19:42, Adam Aglionby wrote:
On Monday, August 3, 2015 at 7:07:46 PM UTC+1, Fredxxx wrote:
On 01/08/2015 21:03, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is
still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.



The problem I have is that there is noticeable changes in light
intensity which becomes very evident when the leds are dimmed.
The best way I can describe it is that the leds look like candle
flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere
in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage
supply. Note that block of flats (7 flats in total) does not
have a gas supply so all of the heating and cooking is on the
electric supply. The leds react faster that the halogen lamps so
that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights
is about 150 watts (20 downlighters plus led strips).


Most traditional/old (leading edge) dimmers are sensitive to mains
noise as they use DIACs as a crude way to time the turn on of the
TRAIC or Thyrister. I've looked at more current circuits,
obviously made to a price, that still use DIACs.

Thats a cheap wall plate dimmer, the Rako`s will use proper zero
crossing detection , MPU and opto isolated triac for firing.

I'm rather cynical of what's in a black box. Microprocessor is
mentioned, but it would have to be if there was a wireless interface.
Many microcontrollers have their own on chip temperature measurement
that might account for this unit's "temperature shutdown" feature.

It`s cheaper nowadays,on the BOM, MPU be cheaper than a diac :-)

even on the `bay, Attiny 13, 50p each

http://www.ebay.co.uk/itm/2pcs-ATTIN...-/141664188426

DB3 diac 20p each

http://www.ebay.co.uk/sch/i.html?_fr...=diac&_sacat=0

On Saturday, 1 August 2015 21:03:56 UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

Thanks again for the responses - very interesting paper Fredxxx. I have spoken to Tech Support at Rako. They agree that leading edge is not the first choice to dim leds. However it can produce an acceptable outcome. As stage one of the experiment they have suggested that I try one of the leds that they have rated as excellent in the tests (eg Enlite by Aurora) in one room. So I wil give that a try.

Mike

On Saturday, 1 August 2015 21:03:56 UTC+1, wrote:
Hi,

I have had lighting installed in my flat. Although my fitter is still being helpful he is running out of ideas.

The lighting is all led controlled using rako rdl250c units:

http://www.rakocontrols.com/products...ne-dimmer.html.

The problem I have is that there is noticeable changes in light intensity which becomes very evident when the leds are dimmed. The best way I can describe it is that the leds look like candle flames. I don't think it is a mains frequency flicker.

Now that I look carefully at traditional halogen lamps elsewhere in the flat I can also detect a less pronounced flicker.

My guess at what is happening is that I have an unstable voltage supply. Note that block of flats (7 flats in total) does not have a gas supply so all of the heating and cooking is on the electric supply. The leds react faster that the halogen lamps so that the intensity changes are more evident.

Any advice or ideas appreciated. The total load of led lights is about 150 watts (20 downlighters plus led strips).

Mike

I have now tried 5 replacement led lamps in one of the rooms. Initial results look promising. The flicker is reduced to the extent that it is not noticeable. I will run them for a while before declaring victory. What I have learnt form this thread is that the source of these flicker problems on LEDs is the interaction between the the voltage control done by the dimmer and the separate voltage reduction done by the circuit in the led bulb itself. Often even though a particular set-up works it might be "only just" working. Then some small difference can turn that into "only just" not working :-). I think my future approach would be to choose a well regarded bulb and then check with the manufacturer for the dimmer which they recommend. Thanks again to everyone for your contributions