On Tue, Nov 15, 2011 at 1:08 PM, Doug Braun <doug@dougbraun.com> wrote:
> I was under the impression that mercury vapor lights are pretty
> efficient- as good as any other type of fluorescent light. B But those
> things (sometimes called "yardblasters") tend to send too much light
> all over the place, including upwards. B You might be better off with
> some type of lighting fixture that has less total brightness, but has
> a better type of reflector that sends the night to where it is
> actually useful (e.g. not the neighbor's bedroom windows).
>
Mercury vapor lights are not as efficent as high pressure sodium
lights, nor newer technology such as ceramic metal halide, induction
lamp, and leds. The production of new fixtures and ballasts ended in
the US in 2008 (I think, might be off a year or so), though new lamps
continue to be available. (They'll be banned outright in the EU in a
couple years.)
One of the mis-features of MV lamps is that their output declines with
age, because the bulb darkens, while still consuming their full
electrical draw.
Since I don't know what sort of fixture Eric's got, I can't comment
about aim and cut off, except to say that MV fixtures ranged from
basically bare bulbs to pretty good zero-light-above-horizon models.
Eric: you might do well to ask your utility about their street
lighting programs. Some utilities have programs where they will
install a lamp, provide the electricity, and do the maintance on it,
for a fixed fee. That can be less than you'd pay for just the
electricity, depending on the location.
--
David Scheidt
dmscheidt@gmail.com
_______________________________________________
Shop-talk@autox.team.net
Donate: http://www.team.net/donate.html
Suggested annual donation $12.96
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|