RE: Dichroic to Dimmable LED - Umm.....

["Darren Karp" <darren.karp@xxxxxxxxx>]

What?



From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of
Richard (lists account)
Sent: 14 January 2010 10:34
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Dichroic to Dimmable LED - Umm.....





After seeing inside several of the available GU10 replacements when they
have died, there is no way I would be considering them dimming or not.

Line voltage smoothed into 400v electrolytic caps, small smd resistors
across the resulting 375v nominal voltage, nothing preventing the board
moving too close to the alu heatsink which is not grounded since it has
none
in the terminal - potential shock hazard there IMO.

And thats before you even try to start dimming a constant current supply
that needs smoothing caps to eliminate flicker with a phase angle dimmer.

It's just not there yet. Even the G5.3 based 12v ones are a pain to try to
control, and IMO as long as they try to be drop in replacements for
incandescent lamps then they will suck for controlling them.

Really there needs to be a current controlled power supply for them, and
someone could make one that has a phase angle dimming input like there are
dimmable CFL lamps, but that would need a different base to prevent mixups
with low voltage AC or DC fittings.

Its great to want to save money and get a decent white light with LED, but
controlling it is something I have given up on for now. Even electronic
transformers make problems with LEDs because of the high frequency that
they
output messing with the rectifiers in some LED replacements.

> -----Original Message-----
> From: ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>
[mailto:ukha_d@xxxxxxx
<mailto:ukha_d%40yahoogroups.com>
] On Behalf
> Of Kenneth Watt
> Sent: Wednesday, 13 January 2010 11:33 p.m.
> To: ukha_d@xxxxxxx <mailto:ukha_d%40yahoogroups.com>
> Subject: Re: [ukha_d] Dichroic to Dimmable LED - Umm.....
>
> Hi Gareth,
>
> I've been going down the same route and, although I'm still waiting on
> a couple to test, thus far the "dimmable drop-in
replacement" doesn't
> work with the X10 modules.
>
> They will dim, they will ramp up and down within a certain range but
> they cut out at the upper and lower ends of the dimming range. Apart
> from which they produce horrendous line noise.
>
> So far I've tried both dimmable GU10 (2 versions, 1 the Cree LED) and
a
> liquid cooled LED SES fitting. I've also fitted a load of GU4 LED
> replacements and, despite being advertised as a "drop-in"
replacement
> for the standard bulbs, they do need pukka LED drivers fitted and not
> the halogen transformers or the LED bulbs have a nasty habit of
> overheating and blowing themselves to bits, literally.
>
> They do not produce the same sort of light (different temperature) or
> as much light IMO as a standard bulb will.
>
> My advice is that they are fine as lights that you want to run for
> extended periods to see where you're going or for security purposes
> but, to have them as replacements for normal lamps totally... I
> wouldn't advise it based on the current crop.



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