Just that guys!. No disrepect to Scott35 or anyone else, but this area of the trade is only recognised when someone has a problem with it. In particular, either Mercury Vapour or Metal-Halide. Having said that, I realise that Scott has (by all of his own work, thanks mate!) posted circuit diagrams of most of the systems of lighting, with respect to Fluorescent and Sodium fittings. There does seem to be however a bit of confusion amongst EC's, as to the difference between Non-Ballasted and Self-Ballasted Lamps. To tidy this all up, could we get a thread going here where we could talk about all of the the lamps in use at the moment?. I'll throw a link up in the General Area, if Paul or Roger can lock it out and make this the one thread. There are a LOT of questions to be asked and answered. I'd like to see a dialouge start. Surely we can all learn from a thread like this?
A very timely topic, as far as I am concerned. I have to admit, I haven't looked through all the past threads on this subject, but I agree that there is always something to address concerning HID lighting.
My business partner and I have been addressing problems in HID lighting for parking areas and indoor plant lighting, off and on for years.
In particular, for outdoor area lighting;
Weather rated 277V / 400W metal halide post mounted parking lot lights, both, large envelope lamps and small envelope, have all the advantages of HID lighting, but we have been running into a problem with the enclosure glass becoming hot, then during rain storms with high winds, driving the rain onto the glass, causing it to shatter.
In high bay applications, large plants in particular, the on site service personel have a tendency to allow a high percentage of lamps to fail before calling an outside contractor to re-lamp. By this time, many ballasts, or starters, have failed due to trying to continuously "start" bad lamps. Rather than spending very costly time in trouble-shooting individual components of the ballast set, we have found it to be more cost effective to replace questionable ballasts with "ballast kits", available at most supply houses now. The problem is, this can get very expensive as well. We try to explain to the site service personel that they can save themselves a lot of money by recognizing when an HID lamp is telling you to replace it, rather than waiting for it to fail, but they rarely follow through.
Discharge lamps certainly are quite interesting devices. They have some unusual electrical characteristics which require delving into quantum physics to explain, and with the staggering variety of different lamps now available even choosing the correct control gear can be a challenge. I can claim a fair knowledge of this area, but there are always new questions that arise. One such question that I have concerns the advisability of running metal halide lamps (and sodium vapour?) 24/7. I have read that it is essential that the MH lamp get a rest for an hour or so each week, minimum, to avoid lamp rupture. Contrariwise, I have seen many lamps run continuously for months at a time without being switched off, but I have yet to see one rupture. If anything, continuous operation seemed to prolong the life of the lamps. Any thoughts anyone?
From the comments above, we should get into a bit of a discussion about this particular part of the Electrical field. To a certain extent, it's filled with a certain amount of mis-information. Not so much from Manufacturers, but people trying to apply a "one size-fits all" attitude, to all groups of lamps and starting gear. Believe me, it isn't like that!.
[This message has been edited by Trumpy (edited 08-16-2005).]
One such question that I have concerns the advisability of running metal halide lamps (and sodium vapour?) 24/7. I have read that it is essential that the MH lamp get a rest for an hour or so each week, minimum, to avoid lamp rupture
I can agree with what you are saying with respect to Metal-Halide, but I would say leaving the lamps off for a longer period would be better for the construction of the lamps (assuming linear type). Let them cool right down. One thing we have had a problem with is Voltage Surges, it will just bust the lamp casing. Best to protect the circuit with Surge Diverters.
This is another thread of major interest! Haven't seen a Self-Ballasted Mercury Vapor Lamp for >15 years!
As stated in another thread today, let me take care of some "Domestic Tasks" (i.e. clothes need washing, bed needs to be made, rooms need cleaning, etc...), along with a few replies, then I'll jump back here with some type of discussion.
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!