Buzzing low Voltage Light

[SBH]

I have just installed a 10*10w halogen low voltage ceiling light with integeral transformer.
Hooked up to a normal switch it works fine, but said it was compatable with a halogen dimmer. I have used a 1 Gang 2 Way iQ 400w Low Voltage Dimmer from TLC, but since I have it has an annoying buzz.

Other than scrap the dimmer and go for a normal toggle, what next?

 

[dingbat]

Define 'annoying'. It's possible you have a faulty dimmer, but more likely that it's just producing the normal amount of buzz... and it just annoys you! You may get used to it in time. Does it still buzz when turned fully up?

 

[SBH]

Thanks, sorry I think I was unclear - its the light that buzzes not the switch! If I change the switch to a toggle - the light is fine, if I use the dimmer the light buzzes!

 

[ban-all-sheds]

Definitely the light, not the transformer?

 

[breezer]

now its even less clear.

first you implied the dimmer buzzes, then you said it was the light, but you also said you have 10 lights, so what is buzzing?

if it is the TRANSFORMER try putting a piece of sheet music in front of it, it is actually humming because it doesnt know the words

seriously, if it is the transfromer (very likely) is the transfromer secured to anything? it should be

 

[SBH]

OK I mis-worded the original. Its a ceiling light with 10 halogen bulbs. It has a built in transformer, all packaged up. If I wire it to a normal switch, no buzzing from he light. I bought the dimmer from TLC as above, and it makes the light buzz, even though its a low voltage dimmer.

 

[securespark]

Joking apart, Breezer, maybe there is a vibration happening in the fitting due to the dimmer not allowing full flow?

PS The words the trannie doesn't know are "She's giving me good vibrations........."

 

[kendor]

when fed by a chopped waveform such as a triac output from a dimmer, windings will pick up the harmonics and vibrate the laminations they are mounted onto which is what the transformer for your lights is doing, normally the choke built into the dimmer will pick up the harmonics and it will buzz rather than the transformer or whatever connected buzzing.
I found this out some years back from a design engineer who gave me advice when i was building a thyristor bridge invertor drive control for a motorised camera crane and the motor itself was buzzing loudly which wasn't acceptable in a studio environment the solution was a rather large choke in a transformer chamber on wheels that sat away from the crane and that removed the buzzing from the motor totally, the choke buzzed instead. So it is normall to hear a buzz from a dimmer especially when it is dimming the lamp low as long as it isn't excessive noise. As for your transformer buzzing is the dimmer switch buzzing also? Perhaps the laminations inside the transformer for the lights are not compressed tight enough and are vibrating?

 

[ban-all-sheds]

Take the light back to the shop, and get another one.

If the second one is OK, then you just had a dodgy one.

If it isn't, then the maker is being economical with the truth when he says that it can be dimmed, at which point you'll have to decide how much you want that light, and how much you want the dimming.

You might be able to fix the problem by opening up the light and moving the transformer out - it could be that the buzzing is being amplified by how the transformer is mounted, e.g. loosely fixed to something acting as a sounding board. Or you might fix the problem by using a better transformer, again in an outboard position - I think it's pretty much guaranteed that the one built into the light will be a poor quality one.

 

[SBH]

Thanks Folks. I suppose its what I thought, take it back! Its actually the second unit as I took the first back as that was buzzing even louder. There does not seem to be much of a buzz from the dimmer switch, so I suppose the question is do I want it dimmed? In reality yes, but I wanted to confirm that it wasn't me being dim!
Looks like the transformers they are using are Cr**!
Thanks again