OK to user a dimmer with ceiling light?

[Azam]

I have a big ceiling light, with 30 small 10W 12V G4 bulbs. I haven't had it installed yet, but wanted to ask if it would be safe to use a dimmer switch with it (30 bulbs might be too strong otherwise). I don't want to damage the transformer as the light was very expensive.

It has a very heavy transformer. It is round and has a diameter of about 20 cm. Is that likely to be a "wire-wound" transformer?

I bought a 400W dimmer, but it says not to use with a wire-wound transformer.

I have rang several qualified electricians and they all give me completely contradictory advice. Some say it is dangerous to use a dimmer with such a light while others say it is perfectly safe and won't damage the light as long as I use a dimmer with more than 300W.

Thanks a million

 

[ban-all-sheds]

Sounds like a wire-wound transformer, so you need a dimmer which can take that sort of load.

IMPORTANT - what do the instructions say about dimming? Are there contact details for getting technical advice from the manufacturer? Can the place you bought it put you in touch with an appropriate dept in the manufacturer?

 

[breezer]

you said

I bought a 400W dimmer, but it says not to use with a wire-wound transformer.

answers your question with regard to this dimmer really doesnt it.

if you are saying your transformer is round, if you mean ring do-nut shape and if its very heavy it sounds like a torodial transformer, theses are the best tranformers you can get, they do not mind being dimmed. the problem is back emf when you have a big coil and you disconnect it you get a large dose of back emf (plain english : a big spark) this spark can destroy most dimmers, i would there for suggest you get a bigger / differnt brand of dimmer

 

[felix]

Are those halogen bulbs you've got in there? Halogens do not really like being dimmed. The envelope has to be very hot so that the halide can remove the tungsten and return it to the filament. The filament is of course b****y hot and the tungsten halide breaks down redepositing the tungsten. If you run one too dim not only will the envelope go dark with tungsten but the halide may attack the cooler parts of the filament instead.