Energy saving light bulb

[John Brown]

"Also I can confirm that it IS the LEDs themselves that can cause interference"

I'm sorry, but I find that hard to believe. What exactly has led you to that conclusion?

 

[beech1948]

incandescent bulbs are still available as "rough use" bulbs. Bought 6 today from my local hardware store.

 

[Phil Pascoe]

As Ed Bray said.

 

[RogerS]

"Also I can confirm that it IS the LEDs themselves that can cause interference"

I'm sorry, but I find that hard to believe. What exactly has led you to that conclusion?

1) Existing ferrite core mains transformer 240v down to 12v. Fed halogen bulbs perfectly. No interference.

2) Replace halogen bulbs with LEDs. Interference.

Double check...

3) Turn LED lights on. Interference

4) Turn LED lights off. No interference.

5) Disconnect LEDs from transformer.

Double double check..

6) Turn lights on (ie power to the transformer). No interference

7) Re-connect LEDs. Turn them on. Interference.

Exact enough for you?

Google gives many instances of this problem. As have other posters in the thread.

 

[RogerP]

...........
Google gives many instances of this problem. As have other posters in the thread.

Similar sort of checking using the display on my HF/VHF transceiver I can see spurious spikes at various points all over the radio frequencies when LEDs are used.

 

[Phil Pascoe]

My LED's are 230v and I have had no noticeable interference.

 

[John Brown]

"Also I can confirm that it IS the LEDs themselves that can cause interference"

I'm sorry, but I find that hard to believe. What exactly has led you to that conclusion?

1) Existing ferrite core mains transformer 240v down to 12v. Fed halogen bulbs perfectly. No interference.

2) Replace halogen bulbs with LEDs. Interference.

Double check...

3) Turn LED lights on. Interference

4) Turn LED lights off. No interference.

5) Disconnect LEDs from transformer.

Double double check..

6) Turn lights on (ie power to the transformer). No interference

7) Re-connect LEDs. Turn them on. Interference.

Exact enough for you?

Google gives many instances of this problem. As have other posters in the thread.

No. Not exact at all.
All you have shown is that your transformer circuitry(designed for 12V halogen filament lamps) in conjunction with the 12V LED units(which may also contain electronics) cause RF interference. What makes you think that a transformer designed for running halogens will work just as well 12V LED lamps? It may well be the extra electronics within the LED lamps, but I still don't believe it's the LEDs themselves. Just out of curiosity, what happens if you run the LED lamps from an old-fashioned iron and copper 50Hz transformer?

If, on the other hand, when you said "I can confirm that it IS the LEDs themselves that can cause interference", you meant to say "the LED lamps themselves", then I have misunderstood you, but you can see how the phrase "the LEDs themselves" could be construed by someone from an electronics background.

 

[RogerS]

"Also I can confirm that it IS the LEDs themselves that can cause interference"

I'm sorry, but I find that hard to believe. What exactly has led you to that conclusion?

1) Existing ferrite core mains transformer 240v down to 12v. Fed halogen bulbs perfectly. No interference.

2) Replace halogen bulbs with LEDs. Interference.

Double check...

3) Turn LED lights on. Interference

4) Turn LED lights off. No interference.

5) Disconnect LEDs from transformer.

Double double check..

6) Turn lights on (ie power to the transformer). No interference

7) Re-connect LEDs. Turn them on. Interference.

Exact enough for you?

Google gives many instances of this problem. As have other posters in the thread.

No. Not exact at all.
All you have shown is that your transformer circuitry(designed for 12V halogen filament lamps) in conjunction with the 12V LED units(which may also contain electronics) cause RF interference. What makes you think that a transformer designed for running halogens will work just as well 12V LED lamps? It may well be the extra electronics within the LED lamps, but I still don't believe it's the LEDs themselves. Just out of curiosity, what happens if you run the LED lamps from an old-fashioned iron and copper 50Hz transformer?

If, on the other hand, when you said "I can confirm that it IS the LEDs themselves that can cause interference", you meant to say "the LED lamps themselves", then I have misunderstood you, but you can see how the phrase "the LEDs themselves" could be construed by someone from an electronics background.

Well, given the context of the thread, only a pedant would pick up on the term LED meaning a single Light Emitting Diode and not as probably everyone else reading this thread has correctly IMO taken to mean the LED bulb plus whatever circuitry is inside it.

Transformer circuitry..."designed for halogen filament lamps"...please tell me how a ferrite transformer might be designed differently to a normal laminated iron cored transformer or more specifically point me in the direction of any academic paper or treatise that says that the two will behave any differently at 50 Hz for halogen lamps as opposed to LED (including any and all wherever appropriate and in the context thereof notwithstanding any other interpretation but fir the benefit of this discussion to mean the 'inclusion of all ancillary electronic components - both active and passive - that may be included within the definition of LED lamp or LED light.) lamps.

 

[themackay]

I have recently built a large extension all lit by LED,s .I have used mostly GU 10 bulbs some are warm white some are daylight and a couple of cool white in the kitchen and have no complaints witht them I have replaced 2 out of 16 so far after 15 months both replaced Free as they come with 5 year warranty.Mine were all bought from led hut or light rabbit on line.Just my opinion

 

[Phil Pascoe]

My wife replaced four while I was in hospital, I think only one was not working but being female she wanted them matching so she changed the GU10's for four 22mm Edison screws :shock: two of which actually work. I've sold the house, so I'm not touching them!

 

[John Brown]

"Transformer circuitry..."designed for halogen filament lamps"...please tell me how a ferrite transformer might be designed differently to a normal laminated iron cored transformer "
It's all down to frequency. The reason that the ferrite cored transformers are smaller and lighter is because the preceding circuitry rectifies the mains and then generates a higher frequency waveform that allows much higher efficiency. Standard iron-cored transformers don't work well at high frequencies.
So your request to show how they'd work differently at 50Hz is nonsensical, as the ferrite cored transformers used in 12V lighting don't work at 50Hz.
If I was being pedantic when I took your phrase "the LEDs themselves" to mean the LEDs themselves, then I apologize for the mistake.

If you take a look at this link:
http://eaas-journal.org/survey/userfile ... gy%206.pdf
You will see the point made about different frequencies at the paragraph labelled 1. Introduction

 

[RogerS]

John, at the risk of repeating myself.

1) The ferrite transformers that I bought and used in situ for the last 20+ years have no preceding circuitry. They do not have any circuitry after them (other than what may be in the LED lamp). Other than the windings they have no other circuitry in them. They are big.

What you say is quite correct but there are exceptions as in (1) above.

I have no idea what circuitry is inside the LED lamps as I've not bothered to take them apart.

 

[John Brown]

John, at the risk of repeating myself.

1) The ferrite transformers that I bought and used in situ for the last 20+ years have no preceding circuitry. They do not have any circuitry after them (other than what may be in the LED lamp). Other than the windings they have no other circuitry in them. They are big.

What you say is quite correct but there are exceptions as in (1) above.

I have no idea what circuitry is inside the LED lamps as I've not bothered to take them apart.

In that case, I wonder what makes you think they are ferrite cored?
In case you wonder why I'm interested, I used to be part owner of a company(Samsons Electronics, also about 20 years ago), that made trarnsformers for twelve volt halogens. They were not ferrite cores, they were toroidal transformers and the core was one piece of iron wound into the shape of a torus. The transformer was then placed in a cylindrical plastic pot of a size that would fit through the hole in the ceiling to be occupied by the lamp, and encapsulated with a potting compound.

 

[RogerS]

John, at the risk of repeating myself.

1) The ferrite transformers that I bought and used in situ for the last 20+ years have no preceding circuitry. They do not have any circuitry after them (other than what may be in the LED lamp). Other than the windings they have no other circuitry in them. They are big.

What you say is quite correct but there are exceptions as in (1) above.

I have no idea what circuitry is inside the LED lamps as I've not bothered to take them apart.

In that case, I wonder what makes you think they are ferrite cored?
In case you wonder why I'm interested, I used to be part owner of a company(Samsons Electronics, also about 20 years ago), that made trarnsformers for twelve volt halogens. They were not ferrite cores, they were toroidal transformers and the core was one piece of iron wound into the shape of a torus. The transformer was then placed in a cylindrical plastic pot of a size that would fit through the hole in the ceiling to be occupied by the lamp, and encapsulated with a potting compound.

Fully understand, John. I've just finished laying down some oak floorboards in my study otherwise I'd have been able to take a photo for you as it sounds as if the transformers are some of yours! You've got me intrigued. Just had a look through the WIP photos but sadly no pictures.

 

[RogerS]

John, please accept my sincere and profound apologies. I remembered that I have a spare transformer and, moreover, not covered in fine dust that led me to the wrong conclusion ( a weak defence, I agree !). Here it is.

Is it one of yours ? It ain't a ferrite.

 

[John Brown]

I don't think so, but I can't be 100% sure. Ours didn't have that hole.

 

[paul-c]

i hope to see a reduction on my leccy bill in the future ( hopefully ) as we have just relaced 43 x 20 watt gu 10's with led's dimmable 5 watt and non-dimmable 1.2 watt.
they are all cool white and certainly brighter then the 20 watt halogen they replaced.
still need to replace another 12 though.
all of ours are 240v and not run off transformers - we were advised to do this as its apparently safer due to no heat build up in transformer.
cheers paul

 

[RogerS]

.....we were advised to do this as its apparently safer due to no heat build up in transformer.
cheers paul

I'd take that advice under advisement TBH.

There is a small amount of energy lost as heat in a transformer and naturally if someone uses the wrong transformer and overloads it then, yes, possibility of fire etc. But TBH most houses have quite a few transformers lurking about the place in various bits of equipment and they've not burned down !

 

[paul-c]

I'd take that advice under advisement TBH.

There is a small amount of energy lost as heat in a transformer and naturally if someone uses the wrong transformer and overloads it then, yes, possibility of fire etc. But TBH most houses have quite a few transformers lurking about the place in various bits of equipment and they've not burned down !

hi roger
i think it was because in a ceiling/roof space with insulation the heat build up could be a consideration - however as you say plenty of people have them without a problem.
anyway they are fitted now and spent a small fortune replacing the halogens with led's - so hoping to get a return by way of reduced electric bill - fingers crossed.

 

[RogerS]

I believe that you're not supposed to put insulation over downlighters and transformers but could be wrong. I do know that you need fire-proof shrouds over halogen lights in there is a habitable room above. As I discovered, some Building Control Officer's have this as a 'pet' topic. Mine tried to get me to put them in an orangery even though it was single storey! Politely told him where he could put his shrouds !!