Stephen Dawson wrote:
"Philip" wrote in message
...

Anyone know of such a thing please.
I am at a loss as I have minimal knowledge of this subject.
I am looking for discharge luminaires with a rough equivalence to 1000w
tungsten/halogen. These will be controlled by either time switches or
dusk/dawn sensors.
Must give a white, not amber/yellow, light.
I've googled for hours and find myself more confused than ever. No doubt I
am not putting the right search in but I don't really know what I'm
looking
for.
Tungsten/halogen I vaguely understand as that is what I use now. Several
luminaires are well past the use-by date. So I would like to replace them
with more modern and efficient units.
Son, Sox, HQI, metal halide ! The choices seem bewildering but, as yet, I
am unable to find a simple explanation or comparison of different types.

Any help would be much appreciated.

Thanks

Philip.




How far are you trying to light ??
You should be looking at either HQI or Metal Halide fittings, may be 400W,
and you can buy these with a prewired photocell.

Regards

Steve Dawson



I believe metal halide has about the same efficiency as fluorescent
(i.e. about 4 times better than tungsten/halogen) so you'd be looking at
about 250W. For a cool white go for a colour temperature of around
4000K. A lower temperature (around 3000K) will give what is confusingly
referred to as a warmer white (more like tungsten/halogen). Any higher
than 5000K will start to look too blue.