Dimmable LED lamps buzzing

[Beeg]

Hi all,

Hoping someone wouldn’t mind answering a quick question for me.

I have 2 dimmable touch lamps in the bedrooom. I have fitted them both with LEDs which are dimmable. The dimming function works fine and there is no flickering, however there is a buzzing noise from the lamp when not on max brightness.

Is this just an (unfortunate) characteristic of dimmer circuits, or could it be the LED lamps are not top quality?

Thanks in advance

Beeg

 

[Rpa07]

Led lamps not top quality is a good bet.
How much did they cost? ask yourself would double the amount be a wise investment considering how long they’ll last.

 

[Marvo]

As per RPA, probably minimal design on the internal dimmable drivers. If your dimmer is trailing edge you could try a leading edge type but it's probably easier to replace the lamps with a different make. Try an Enlite / Aurora if you can find something suitable in that make.

 

[Beeg]

Thanks RPA and Marvo. Replacing the dimmer isn’t really an option as it’s built into the lamp itself.

The LED lamps were about £4 from Wilko so probably not best quality.

Thanks for advice, will have a look at investing in some higher quality ones.

 

[Marvo]

Ahhh, apologies, I didn't realise the dimmer was integrated into the actual lamp itself. I have very little experience with these types of lamps, I don't use them because of reliability issues. If it's just one of them buzzing you try take it back and exchange it under warranty and hope the new one is better. If it's both buzzing I'd honestly just get a refund and put the money towards a reputable make dimmer.

 

[Shoei]

It's usually the dimmer in the lamp that buzzes, some LEDs buzz a bit but most likely cause is movement between components in the dimmer. It's not a problem unless the noise bothers you, in which case the best bet is probably to replace the lamp.

 

[Beeg]

Thanks everybody for all your help. The issue is present on both lamps, however I have tried a dimmable halogen and the buzzing noise disappears.

 

[suffolkspark]

The lamp will be designed for the halogen bulbs. Not LEDs. They will be below its design threshold of wattage so its just a bit upset. May fail prematurely so just leave halogens in

 

[Beeg]

The lamp will be designed for the halogen bulbs. Not LEDs. They will be below its design threshold of wattage so its just a bit upset. May fail prematurely so just leave halogens in

Thanks suffolkspark, I had thought of trying this but everywhere seems to be only selling LEDs now Guess I’ll just have to put up with the buzzing noise for now until the lamp fails

 

[suffolkspark]

Thanks suffolkspark, I had thought of trying this but everywhere seems to be only selling LEDs now Guess I’ll just have to put up with the buzzing noise for now until the lamp fails

The dimmer unit in the lamp may possibly fail too as its working outside the paramerers it was designed to.

 

[telectrix]

what you are doing is like running a petrol car on diesel. incompatibe.

 

[Shoei]

I wouldn't want to overstate the problem of a bit of buzzing from a mains dimmer. The dimmer in these lamps is a capacitive touch switch/triac driver doing phase-angle control of a triac, typically a BT136 or the like.

A resistive load like a filament limits the rise time of current when the triac switches on part way through the mains cycle. An LED load contains a mains filter which looks like a low impedance to the triac, so when it switches on there is a current spike which generates enough field to move the triac. Hence the 100Hz buzz, which is normally harmless, if a bit irritating.

It can be fixed by securing the triac better. I've used flame-retardant potting compound but other methods such as retardant heatshrink can be used. Sometimes just moving the triac a bit can stop the buzz.

The usual failure mode is the triac gets popped when its filament lamp load reaches end of life and zaps it with a big current spike. They can be repaired by replacing the triac, which is normally when some work on securing it is needed.

 

[Rpa07]

I wouldn't want to overstate the problem of a bit of buzzing from a mains dimmer. The dimmer in these lamps is a capacitive touch switch/triac driver doing phase-angle control of a triac, typically a BT136 or the like.

A resistive load like a filament limits the rise time of current when the triac switches on part way through the mains cycle. An LED load contains a mains filter which looks like a low impedance to the triac, so when it switches on there is a current spike which generates enough field to move the triac. Hence the 100Hz buzz, which is normally harmless, if a bit irritating.

It can be fixed by securing the triac better. I've used flame-retardant potting compound but other methods such as retardant heatshrink can be used. Sometimes just moving the triac a bit can stop the buzz.

The usual failure mode is the triac gets popped when its filament lamp load reaches end of life and zaps it with a big current spike. They can be repaired by replacing the triac, which is normally when some work on securing it is needed.

In 4 words - Go Back To Halogens

 

[dmxtothemax]

The dimer in the lamp base was probably designed for incandesant lamps, just because a LED lamp says dimer compatible doesn't mean ALL dimers, it means LED dimers, which are different to normal incandesant dimers. I would just go back to a incandesant lamp.
One small incandesant lamp is not the end of the world !

 

[telectrix]

is dimer the aussie spel of dimmer? .

 

[dmxtothemax]

it's awe-stray-un spelling,
We gave up on english long time ago.

 

[Beeg]

Thanks everyone for all your replies.... managed to but an incandescent and all is quiet again