Was wondering if its possible to fit a dimmer to low voltage lights with a
transformer. Was looking for a remote control one, but keep reading that its
not possible to use one but have read a few post about them being used
what's the correct procedure.
AFAIK, Halogens with an electronic transformer (much lighter than iron cored
one) can be used with a dimmer designed for use with such things.
Those with ordinary iron cored heavy transformers cannot be used with dimmers
due to their inductance upseting the triac control and possibly overheating the
transformer arising from a DC component fed to the transformer.
My experience with these was that, although they dim ok, the use of a dimmer
makes the transformer buzz unacceptably - even when the dimmer control is
set to full power.
It may depend on how much you pay - and these were relatively cheap ones
from Screwfix - but they were claimed to be dimmable and compatible with the
In the end, I did away with the dimmers and resorted to switching the lamps
in banks. [I have 12 lamps in 3 groups of 4, with each each group having its
own switch and transformer].
My experience has been the reverse of Bobs - I have been using low voltage
Halogen lamps via standard transformers and a dimmer for the last ten years
without any problems. I started with electronic transformers but they did
not like dimming lights less than 50% before they cut out. They also didn't
last long and I replaced them with standard transformers. Because the
switch on current is higher with inductive loads, I took the precaution of
halving the power rating of the dimmer. Read the manufactures spec
carefully before you buy.
So OK, how am I meant to know if I have a electronic transformer, or an iron
corded one. The light set came with 3 halogens with a transformer, will it
say on the transformer if it is electronic or not, and where do u recommend
I buy a inductance dimmer?
An electronic transformer weighs a few ounces and is generally an
oblong shape, about 4cm by 4cm by 15cm.
An iron cored one will weigh a few pounds and be a lot larger, e.g
150W toroidal approx 18cm diameter and 10cm high or laminated iron
10cm by 10cm by 15cm.
This is a 50VA toroidal weight 750g (approx 2lb)
And a list of bare transformers:
Hope this helps.
On Thu, 4 Sep 2003 08:18:20 +0100, "The Question Asker"
A dimmer suitable for a transformer will work ok with a resistive load -
although it's more expensive. Any electrical wholesaler should have them -
as do some of the sheds.
The lighting set should say what dimmer is needed and whether it is
suitable for dimming.
LV transformers are usually round and heavy. Electronic, or SMPS types,
are usually rectangular and light.
*The sooner you fall behind, the more time you'll have to catch up *
Dave Plowman email@example.com London SW 12
Yews its possible, and I have done it.
I used stansdard dimmers and electrionic transformers that were sold as
'dimmer capable' and indeed they are.
I believe its also possible to get dinmers that will handle the load f a
toroidla transformer as well. But no one seemd to give me a definite YES
when I asked, so I didn't use toroids - which I prefer cos they buzz
less, and are probably more simple and roubust creatures.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.