As Rishi advised, I chose a metal-halide (Hg-I) high intensity gas discharge bulb, OSRAM PowerBall HCI-T (see the specs), 150W, NDL (neutral day light), with good, even, white spectrum. The luminous intensity of this class of bulbs is about 10 times greater than that of the conventional halogen bulbs, not to mention the old incandescent bulbs. So, my 150W bulb shines like a 1500W halogen and it really makes my room look like a bright sunny day. Also, because this lamp is very energy-efficient and does not heat, I can leave it turned on all day long, so that my eyes are more relaxed at average.
I bought the bulb bundled with the LIVAL Hawk projector (see the specs), wide-flood (44 degrees) beam, and installed in on a ceiling track. I can move the projector and direct it where I like. The control gear is conventional, although it also ships with the full electronic control gear, I didn't want to wait for the next supply.
These are quite expensive toys. The projector is US $240, including the bulb which itself is about $40, and the 2m track and all its parts about another $40.
The following are my general impressions:
1. This projector, and all other projectors for such bulbs, look quite BIG. Mine is over 12 inches long and 11 inches wide. It was certainly not intended for home installation and I had pretty hard time convincing the salespeople that I knew what I was doing :).
2. The salesman also claimed that it's going to be too bright for a home room, but it appears to be absolutely OK for my purpose. The brilliant light casts contrasting shadows and the Snellen card looks like perfect black letters on a perfect white background.
Moreover, the light beam (44 degrees) is somewhat too narrow. If you want to flood the entire room with bright light, you may need two or three projectors. There have been also double-ended rectangular projectors with "very wide flood" beam, which I could consider as more appropriate, but I decided for the narrower spot light, because it fits better for sun treatment.
Compare with other home lights3. The color of the light is pure white, meaning that the rest of home lights look like dingy yellowish candles. I wouldn't like to use other lights in the room while the projector is on.
4. The lamp does NOT utter any humming noise, as older gas discharge lamps I heard did, even though the control gear isn't electronic. What I do notice sometimes is that the light is slightly flickering. Not like fluorescent lamps with their nauseating 50 Hz vibration, you know, but there is a hardly noticeable shivering. I wonder if this is because the control gear is not electronic, or if it's a nature of the gas discharge .
5. The lamp does not ignite instantly and it takes about 2-3 min for the lamp to reach its working level of brightness and color. Also after turning off, it cannot be immediately turned back on. This inertia is due to the process of metal evaporation inside the inner capsule of the bulb. The lamp also lives longer if it's not turned on and off too frequently. By the way, the lifespan of this lamp is about 6 times longer that halogens.
Compare with a 500Wt halogen (on the left)
4 comments:
Hi. Did you install this lamp yourself? Also, how long were the tracks you got with it? And doe the projector swivel? Cheers, Joe.
Yes, I installed the lamp myself.
There are two types of mounting available for the lamp: "plate" and "rail". The plate can be installed on both walls and ceiling, and the rail can only be installed on the ceiling AFAIU. The lamp itself swivels 360 degrees around its axis and almost 90 degrees perpendicular to the surface. The plate fixes the lamp in a single point whereas the rail additionally allows to slide the lamp across the room. So I've chosen the rail mounting.
I made a few holes in the ceiling with a drill and fixed the rail using dowels. Then I made the necessary electrical connections to the rail. Then I hung the lamp onto the rail.
Note that the entire construction looks pretty industrial, not home-like, so most visitors of my home get shocked and awed both by the brightness of the lamp and its look, but I don't care if they think I'm a freak :).
My installation of the lamp is though not perfect for all purposes. For example, to look closely to the lamp, I have to stand up on a chair and throw back my head, so my neck quickly begins aching. I could have installed the lamp on the wall using the plate and be able to look at it with more convenience and for longer time.
Thanks for your last reply. I may be able of get hold of one of those. Would you mind answering some more questions though?
Does the lamp plug into the mains? That is, does it come with a plug, or did you have to wire it yourself?
Also, I understand there is a plate to mount to a wall with... Could you also mount on a surface? You see, I also have a small platform in my room that may be a good surface for the lamp.
When it is mounted on the plate can it still swivel like it can when on the tracks?
Lastly, what are the approximate dimensions of the lamp?
Sorry for all the questions, it has proved quite difficult for me to get hold of a suitable lamp, it seems metal-halide lamps aren't meant for consumers....
Cheers,Joe
Here are the answers to your questions
> Does the lamp plug into the mains? That is, does it come with a plug, or did you have to wire it yourself?
No, there is no mains plug. More exactly, the projector has a special plastic connector on its bracket (see the photo in the post) that you plug into the rail, or the plate mounting. You can connect several projectors to the same rail (and they do, like in showcases). Then you connect the rail or the plate to the mains. In case of the rail, there is a special rail terminal plug that you should also purchase. The wires that you connect to this plug with one end, you should also fit to connect somehow to the mains with the other end, be it a standard mains plug or directly to naked wires using contact bridges. In my case, I connected the wire in parallel to my existing ceiling lamp, and also wired an additional switch to use them both alternatively.
Connecting the plate mounting to the mains I believe is much similar.
> Also, I understand there is a plate to mount to a wall with... Could you also mount on a surface? You see, I also have a small platform in my room that may be a good surface for the lamp.
Do you mean on top of a horizontal surface? I don't know if it's possible. The spec says that with the plate mounting the projector can be installed on a vertical wall, but even this makes me actually doubt. The projector is pretty long and heavy, and the connector on its bracket does not seem very solid to stand its own weight momentum when mounted on the wall. I can only find this out if I get to try the plate mounting. :)
> When it is mounted on the plate can it still swivel like it can when on the tracks?
Yes, it can swivel the same, because it swivels relative to its bracket and the bracket swivels relative to the connector. But you can't slide it if you don't have the rail, of course.
> Lastly, what are the approximate dimensions of the lamp?
I wrote it in the blog post. It is over 12 inches long and 11 inches wide. Note that you can also find these and other spec data on the website of the manufacturer (the link also given in the post).
P.S. I am finding recently that over time the lamp begins to produce an increasing amount of humming noise, which is noticeable in night time, when it's quiet. Next time I would consider getting the automatic gear, hopefully it doesn't have this drawback.
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