Re: Part P

[Simon Haslam <simon_haslam@xxxxxxxxxxx>]

When 12V halogens first came out they were often connected with up to
10 or so on one transformer. I think the problem then was that when a bulb
blew (which they invariably do relatively often) there could be a surge
which would cause other bulbs to fail too.

These days the transformers are electronically regulated (decent ones like
Osram anyway) to provide a soft start (which improves bulb life) and so may
not be so susceptible to surges. The convention still seems to be to have
multiple transformers, though depending on what size bulbs you use (and new
higher efficiency 12V bulbs use less power for the same light output) you
can quite happily share two or more fittings per transformer (I have 2 per
transformer in my kitchen ceiling, or 4 for cupboard 10W accent lights).

Finally you also want a transformer that you can get at, especially if the
floor above is occupied, typically through the fitting. Therefore that
limits the size (and so power output) it can be.

Note: I'm not a spark so much of the above is speculation ;-)


Simon

--- On Mon, 3/5/10, Mal Lansell <mal@xxxxxxx> wrote:


Oh, and now my rant is nearly done, can anyone explain why each 12V bulb

should have its own transformer?  It seems so wasteful.



Mal




















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