Re: FW: FW: Fwd: Wall switch dimmers work with 12v halogen?

["Timothy Morris" <timmorris@xxxxxxx>]

Nigel, I've received a reply from X10. This seems to make sense, I think
the
thing to do is try it with the transformers, and if it doesn't work swap
them out for 240V bulbs, care to  comment?

Tim.

-----Original Message-----
From: X10PROTEC@xxxxxxx [mailto:X10PROTEC@xxxxxxx]
Sent: 17 March 1999 14:15
To: timmorris@xxxxxxx
Subject: Re: FW: [ukha_d] Re: Fwd: Wall switch dimmers work with 12v
halogen?


In a message dated 3/16/99 4:16:44 PM Pacific Standard Time,
timmorris@xxxxxxx writes:

Let me clarify what you read and what you think that you read...as I told
you
in my earlier message, I normally do not deal with international products,
as
I have no way of testing them here in the States. However, our VP of
Technical
has stated that this switch is a dimmer and I can tell you that if it is
merely called a dimmer that means that it is an Incandescent or Resistive
load
dimmer. What you have with a TRANSFORMER IS AN INDUCTIVE LOAD. Inductive
loads
do not use resistance to the AC wave form to cause heat which in turn
causes
light (as resistive loads do), they actually change the wave form through
the
transformer to a different wave form (stepping down). This stepped down
wave
is much less than the original, thus running your low voltage lights.

But the lights are not the problem, the inductive load transformer is. Our
switch is designed to use the wave form in it's original form. Any
variation
from that will cause the switch to act erratic. So you must use an
inductive
dimmer, please do not ask me to recommend one, I am not familiar with the
international products.

<< From:	timmorris@xxxxxxx (Timothy Morris)
To:	x10protec@xxxxxxx

I received a reply to my original question from another source. What he
appears to be saying is that provided the switch is installed on the 240V
side of the wiring AND the transformers are marked as "suitable for
dimming"
then ANY dimmer should work with low voltage lighting. P{lease could you
check for me again.

Tim.

-----Original Message-----
From: Nigel Orr [mailto:nigel.orr@xxxxxxx]
Sent: 15 March 1999 16:58
To: ukha_d@xxxxxxx
Subject: [ukha_d] Re: Fwd: Wall switch dimmers work with 12v halogen?


I'm not sure who wrote what, but anyway...

At 11:09 15/03/99 EST, you wrote:

> Trevor (at AHA) has been advised by Home Control plc (the UK
distributors
of
> X10Pro) that the wall switch dimmers will work with low voltage
halogens
up
> to a total load of 300W per switch. We are both slightly dubious about
this.

Why?  As long as the 'transformer' is marked as suitable for dimmers, it
should work, with only two problems... halogen lights are designed to run
at full power- at slightly reduced power,
1) Their life will be shortened, and
2) light output will fall off much faster than expected with applied power.

I may have some of the 'technicals' mixed up, but the basic reason for 1)
is that halogens need to run at full power to avoid the vapour from the
element being deposited on the glass envelope.  If they are run at lower
power, the temperature is so low that the vapour from the element condenses
on the glass.  Over time, if they are never run at full power, the element
will break prematurely.  This can be avoided by running them at full power
every so often.

I guess both these problems occur exactly the same with mains powered
halogens, but I've never used them so I couldn't be sure...

>I am not aware of the operational characteristics of the international
>devices. However I copied this to our Technical VP, and here is his
response.
>"The operative word here is Dimmer. The LW10U is a dimmer and as
such
cannot
>control low voltage lights."

Someone's Technical VP seems to have a bit of technical confusion... note
that the dimmer would have to go on the 240V side of the lighting, not the
12V side (maybe he meant LW10U is a _mains_ dimmer, with the operative word
being mains?), but it should work, with a dimmable transformer, for
suitable values of 'work' as explained above...

Nige >>


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