Re: X10 dimming

[Raymond <Reb.barnett@xxxxxxx>]

I checked my halogen uplighter last night, and on it's dimmest setting
the filament still glows slightly. This leaves me in a bit of a quandry:
either the dimmer is really clever and implements the 'pre-heat'
facility Keith describes, thus prolonging the filament life (at the
expense of my electricity bill!); OR, the filaments are running hot
enough for the tungsten to gradually evaporate but cool enough to
condense on the glass (as described by Nigel previously), thus reducing
the life of the filaments if I run the lamp like this for any serious
amount of time...

I suppose I'll just have to suck it and see... Halogens aren't all that
expensive for a one off experiment???

On a similar note, Tim Morris recently posted about Homation 2000 and
said
It does allow soft start with controllers
that have to go "full on" before dimming
How does it do that? Is it just doing it the simple way, keeping the
light barely on, or is them some much cleverer process...

Ray Barnett.

> -----Original Message-----
> From:	keith.doxey@xxxxxxx [SMTP:keith.doxey@xxxxxxx]
> Sent:	29 March 1999 23:47
> To:	REB.Barnett@xxxxxxx
> Subject:	[ukha_d] Re: X10 dimming
>
> Adding to Nigels comments about the dimmer passing little or no
> current at
> its lowest setting.
>
> Most good commercial dimmer packs used in the entertainment industry
> have a
> feature called "Pre-Heat" which basically does what you are
> describing. The
> dimmer passes just enough current to keep the filaments warm to
> eliminate
> the surge when the lamp is turned on. There is no detremental effect
> to the
> dimmer as long as it has an adequate heatsink to disipate any heat
> produced.
> There is a positive effect on the lamps in that they last much longer
> due to
> being pre warmed.
>
> You may notice a slight increase in power consumption as the circuit
> would
> be consuming a few watts at all times.
>
> A way around the constant consumption would be to actually turn the
> lamp off
> at times when it was not going to be used. For example, if you have a
> home
> theatre but only ever use the room between 7pm and 1 am then control
> the
> module like this
> 6:45pm Lamp On, dim down to zero
> 7 pm to 1 am use the module as you want with the simulated soft start
> 1:15am Lamp Off until 6:45 the following night when you set it up for
> soft
> start again.
>
> Hope that helps
>
> Keith
>
> Keith Doxey
> http://www.btinternet.com/~krazy.keith
> Krazy Keith's World of DIY HomeAutomation
>
>
> > -----Original Message-----
> > From: Nigel Orr [mailto:nigel.orr@xxxxxxx]
> > Sent: 29 March 1999 09:42
> > To: ukha_d@xxxxxxx
> > Subject: [ukha_d] Re: X10 dimming
> >
> >
> > At 11:00 26/03/99 -0000, you wrote:
> >
> <SNIP>
> > >I'm concerned because I don't properly know how the
> > >dimmer works, and I do know that the cold resistance of
lights is
> very
> > >low, and hence am I pumping loads of current through the bulb
when
> I
> > >think it is off? If current is flowing, is it likely to
reduce the
> life
> > >of the bulb and will it kill the dimmer?
> >
> > The dimmer works by switching on the mains at a variable time
after
> each
> > half-cycle starts, and switching it off at the end of the
> half-cycle.  0%
> > means the dimmer switches on at the end of the half-cycle, and
100%
> means
> > it switches on at the beginning of the half-cycle.  50% means it
> switches
> > on at the peak of the supplied voltage, the sudden switching
> > action is what
> > makes dimmers electrically and acoustically noisiest at 50%.
> >
> > As for the dimmer, it depends how well it is designed... there
are 3
> > scenarios:
> > 1) It is fully dimmed down, so it will not supply current to the
> light.
> > If that is the case, the dimmer will still be dissipating a small
> > amount of
> > heat, so its lifetime may be reduced slightly, but if it doesn't
> feel warm
> > after 24 hours, it's probably not going to have much effect.
> > 2) It is supplying about 10% of power
> > If that is the case, it probably will get 'tired' more quickly
> > 3) It is 'intelligent' and goes into some sort of standby mode
when
> dimmed
> > to minimum.
> > If that is the case, it's 'designed' to run at minimum power, and
> > so should
> > have no problems...
> >
> >
> > Which _is_ a good thing for tungsten and tungsten/halogen lights.
> >
> > Nigel
> >
> >
>
>
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