RE: Dimming Low Voltage lights

["Hawes,Timothy Edward (GEG)" <haweste@xxxxxxx>]

Rob,

I've found your transformers on the 'net, here: http://www.domusline.com/home.htm
scroll down to transformers & Set70 - do yours look like this ?
The blurb does say "electronic" but doesn't say
"dimmable". I've been sorting through some old Selfbuild messages
and they seemed to indicate that the transformer should be both
"electronic" *and* "dimmable". Sorry if I mislead you
with my earlier post.

As for "suck it & see"  - I'd be inclined to at least email
the manufacturer regarding dimming before trying (mailto:sales@xxxxxxx). I had assumed you'd
bought the lights and transformers separately - rather than in a set. It is
more hassle to change them then. You can buy just the Varilight
transformers without lamps from B&Q, TLC etc.

The old advice was to use one transformer per light. This can work out to
be supremely expensive. The driver was, IIRC, that if 1 t/f feeds many
lamps, and 1 lamp blows, the remainder are subjected to a higher voltage
and wear out more quickly. It's mitigated somewhat by better regulation in
the electronic transformers, and by keeping spare bulbs and replacing
immediately when one blows. I'd use both transformers if it were me (since
you already have them anyway) - what's the combined load of the lights ?

Not a definitive answer, but hopefully a bit more to go on.

Cheers,

Tim H.


-----Original Message-----
From: Robert Chasmer

Hawes,Timothy Edward (GEG) [mailto:haweste@xxxxxxx] wrote:
> Those switches are only suitable for dimming "dimmable"
> transformers - quoting: "Designed to control dimmable low
> voltage lighting transformers"  :-)
>
> The transformer will say something like "electronic" or
> "dimmable" on it.

Ok I've just had a look at the transformer that came in the box and it does
indeed say "electronic".  I've got two of these transformers,
each one is
like a long box of cooks matches, and four halegon lights.

The full description (incase it means something to someone):-

DOMUS Line srl                 SET-70F (20-70VA)
ELECTRONIC TRANSFORMER FOR LV-HALOGEN LAMPS
PRI.:230V~50HZ 0.30A Cos = 0.99
SEC.:11.6V~eff Max. 5.8A 20-70W
Ta:max. 50'C Tc:max. 75'C at 70W
SELV EQUIVALENT etc..


> The safest way maybe to just replace the transformer with one you
> *know* to be dimmable e.g. the Varilight transformers from B&Q,
> TLC etc. B&Q have them in-store, but not on the website yet.
> They're available in 6.5 A & 9.5 A ratings (on the LV side) and
> two transformers side by side are about as big as a box of Cook's
> matches.

Well I'm happy to have a look in B+Q but I'd take back the trasnformers and
lights  I got from MFI, theres no point in me paying for the lights twice.

Would you try these transformers out on a dimmer switch?
Also on the end of the transformer is a socket which looks like it will
take
6 lights, should I use both transformers or is it ok to use just the one.

Thanks in advance


Rob

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> HTH,
>
> Tim H.
>
> -----Original Message-----
> From: Robert Chasmer
>
> Paul [mailto:groups@xxxxxxx]
wrote:
> > You'll need to get a special kind of dimmer that can cope
> > with this kind of load - don't use a standard dimmer!
>
> http://www.diy.com/bq/product/product.jhtml?PRODID=15508
> http://www.diy.com/bq/product/product.jhtml?PRODID=15509
>
> So is this the sort of thing you meant.  How will I know if
> the transformer
> is happy for its mains input to be dimmed, do I just suck it an see?
>
>
> Rob

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