Dimmer with Halogens - flickering and noise

[baleineau]

I have a ceiling light (chandelier) that has 12 lamps. It is recommended that each is 10w. Thus 120w.
However, my recently-purchased and electrican-fitted dimmer is causing problems. The lights hum/flicker when dimmed to the extent that i have to have them on full power. Which defeats the intention of having a dimmer. The dimmer supports 250w and is thus more than double the capacity.
I have tried using 12 lots of 5w bulbs but the problem of noise/flicker is WORSE.
I don't understand what is wrong. The dimmer's two other gangs power up 2 other lights in the house perfectly well (they are 4 x 40w halogens), thus more consumptive. They dim perfectly without noise.
What else can I try? THANKS.

Martin

 

[Diyisfun]

Are these 10w bulbs..low energy?
or
standard icandescent

 

[baleineau]

they are normal halogen bulbs (G4 Type), 5W and 10W, not energy saving bulbs.

This is the light fitting:

http://www.diy.com/diy/jsp/bq/nav.j...refview=search&ts=1257172691779&isSearch=true

i have tried 10w (which came with the light), and also bought 5w. The outcome was worse with the 5w bulbs.

 

[Aragorn84]

I think G4 is 12v, meaning they're run from a 12v transformer, and these things often dont agree with dimmer switches.

 

[ban-all-sheds]

my recently-purchased and electrican-fitted dimmer is causing problems.

Did you buy it and ask the electrician to fit it, or did you ask him to supply & fit?

 

[johnnykc]

first question is whether or not it is a dimmable fitting? ....

you'll have to check that with B&Q as the chinese sweat shop that supplied it probably have no contact details on the box...

 

[baleineau]

i bought it from B and Q first and the got the electrician to fit the dimmer. the two other light fittings dim perfectly, but am surprised with this other one because the dimmer (250w) should accommodate the light fitting.

would it help to remove some of the bulbs? i'm just concerned that it performs worse with 5w bulbs than 10w bulbs, therefore if i just put in 8 10w bulbs it will work worse than 12 10w bulbs.

Is there a risk of electric shock or the bulbs blowing completely, or is it just noice/flickering that's the risk??

 

[Aragorn84]

The problem isnt the dimmer, its the fact that the fitting isnt designed to be dimmed.

Chances are if the transformer is making a racket then its at risk of premature failure, and the bulbs probably wont like the flickering too much.

 

[johnnykc]

If its not a dimmable fitting .....it doesn't matter what you do with the lamps....

 

[tim west]

If I was diagnosing the problem first thing i'd do would be remove the fitting and replace with a pendant and 100w tungsten lamp to check the dimmer works properly.

are the lamps in the fitting 12v?

if so then the dimmer might not be seeing enough load due to the transforrmer inductance (presuming a wire wound)

you say the others work ok, are they both on one dimmer?

 

[ban-all-sheds]

am surprised with this other one because the dimmer (250w) should accommodate the light fitting.

would it help to remove some of the bulbs?

Did you not read Aragorn's post made at 14:41?

 

[baleineau]

obviously i read it, but that doesn't mean i understood it.

 

[baleineau]

are the lamps in the fitting 12v?

if so then the dimmer might not be seeing enough load due to the transforrmer inductance (presuming a wire wound)

you say the others work ok, are they both on one dimmer?

the lamps in the fitting are 12v.
the dimmer is a three gang type supporting three separate lights. the other two work properly. they each take halogen 40w bulbs (4 in each lamp).

having paid an electrician already to fit the dimmer I'm loathe to start taking apart the dimmer and swapping anything around.

i've contacted B&Q (they sold both the dimmer and the light-fitting) to check about compatibility. I only bought these items a few weeks ago and have the receipts, but no packaging. I will take it all back if the light I bought cannot be dimmed. What is the use of such a light???

 

[ban-all-sheds]

I think G4 is 12v, meaning they're run from a 12v transformer, and these things often dont agree with dimmer switches.

 

[baleineau]

I think G4 is 12v, meaning they're run from a 12v transformer, and these things often dont agree with dimmer switches.

and your point? it means they often DO agree with dimmers as well, so it didn't really take me much further with my query.

but thanks anyway