These are links to the Metal Halide Lamp Q&A section at the National Lighting Products Information Program.

Click a link below:

How do metal halide lamps work?

What is the difference between probe-start and pulse-start lamps?

Why do metal halide lamps require a ballast?

What types of ballasts are available to use with metal halide lamps?

What effect does burning position have on metal halide lamps?

What are warm-up and restrike times for metal halide lamps?

What safety issues should specifiers consider?

FlyBoy,
Thanks for the informative posting.
John

Nice Job

Hello! Justo bought my luumenlab guide:D really nice, and the protected forums are way better than normal ones.

On the "What safety issues should specifiers consider? " link said this:

MH lamps carry ratings such as “E” (Enclosed), “S” (Suitable), and “O” (Open/closed) that identify under what conditions they should be used. According to American National Standards Institute (ANSI), the “E” rating refers to lamps that must be used in enclosed luminaires that meet the safety requirements of UL1598. The “S” rating refers to lamps that are considered suitable for open luminaire operation only if operated in the vertical position ±15° and turned off at least 15 minutes per week. Group relamping is required before reaching rated life (see Figure 3). The “O” rating refers to lamps that can be operated in both open and enclosed luminaires. The manufacturer's product information indicates the ratings and specifies how each type of MH lamp can be safely used.

Like fluorescent lamps, MH lamps contain small amounts of mercury. One should always wear gloves when handling broken lamp fragments, and always dispose of spent lamps according to waste disposal guidelines established by the U.S. Environmental Protection Agency (EPA) or other appropriate state or local authorities.

Didnt know about the mercury thing

So.. what type are lumenlab´s lamps: E, S or O? and are they for " Universal " Positioning or only horizontal to a certain degree?


Thanks.

Alejandro..

http://www.ushio.com/files/Ultra-ArcSpcSht0604.pdf points out that USHIO-S400DD is the type S - "Enclosed Fixture Required"

I looked into these safety ratings a while ago and this is what they refer to: if for any reason the outer envelope of the bulb would break or explode something has to be around to contain it and the glass pieces would not danger people. If you look at the brochures the bulbs with the open enclosure rating have an extra glass tubing around them. This is very similar to the procedure done with the 50W halogen lights.
With the projector enclosure around the bulbs they are perfectly safe to use; the only thing has to be controlled is the surrounding temperature.
By the way, these type of bulbs are very tough. I have seen one overheated so much that the outer envelope was half molten but the inner spark chamber was still intact.

Forkev, I think you meant to say that the S400DD is the type E - "Enclosed Fixture Required."

I went to the link you posted and this is what I saw on page 2:

"Burn Cycle: 11 hours ON and 1 hour OFF(Recommended shut down 15 minutes per week)"

Which is it? 11 on and 1 off, or shut down 15 minutes a week? I am very confused. Anyone know?

I just received by S400DD bulb, and I see a metal ball rolling around the arc chamber. Does anyone know if that is normal? It seems odd to me that it's in there in the first place.

Yeah that's normal... it's mercury.

Ok, thanks for the reply. At first I was worried that the ball would make the bulb explode. lol. But now I realize that it probably melts from the heat...

Is it me, or is mercury supposed to be a liquid at room temperature?

You are not supposed to be liquid at room temperature! But then your'e not in a vacuum which is my guess as to why it appears solid but is in fact a liquid ball.

Metal Halide bulbs are not vaccums. They have high pressure, remember?

OK my bad. It may be the high pressure causing the ball then.

It's such a small ball that the surface tension will pull it into a sperical shape rather than a glob. Never broken a thermometer?

Mercury thermometers in this country are not that common, they normally use some kind of red dye instead.

Thanks for the correction, DeathRay64, I didnt think about surface tension!

Can anyone tell me what is the best ratings for the metal halide lamps are suppose to be. Like the output lumens, color temp, and CRI. I gather you would want the best CRI you can get like 65 to 100, the highest output lumens, and the the color temp close to 4000k, but what is the min and max and or best rating for the project.

Thanx

I think people are using lamps from anywhere between 4000k (a bit yellow) to 5200k (a bit blue), and it depends largely on personal preference. 4200k is a good compromise.

Lumens should be above 30,000, no maximum as long as you dont go above 400w.

CRI I believe doesnt vary much but 65 should be fine.

thanks for the information. I will try to put it to good use.

No problem dosvolden. What you have to be more careful of is the overall size of the lamp, so it fits properly in your enclosure! You dont want a beast like the original lamp the guide recommended!

New to the forum.
First post...
I built a projector in 2 weeks and I am really happy with the results.
Version 2 will have many upgrade.
The first on I built was more or less proof of concept to the other half so I could get the buy in for more funding.

I found this item online and thought I would post some info on it.
Looks like it may work.
Self contained 400W Metal Halide bulb, ballast, wire, enclosure, and glass shield.

What do you think?
Cost is $198.00



http://www.elights.com/rabf2flood40.html

Might be to large, but could work well in a folded design...

And another flood.
Smaller, but more expensive...
This is almost a perfect size...
I wonder what the weight is and what type of ballast is used...
400W Metal Halide Flood

The reflector isn't right and the bulb and ballast can be gotten elsewhere for $100-$150 so these prepackages lights don't make much sense.

Yep, for the ballast and lamp in that rig you're looking at $70 combined max. The 'reflector' is useless to us..

Would it be possible for someone to put in one post the different bulbs we have seen; the big one, the eye bulb, the t-15, with the ballasts available, benifits of each (strike and restrike time, brightness, etc..) and type of base?

I have an old MH400 with a coil and core and mogul base and am thinking of upgrading but what can I keep for which bulb and so on.

jim

Okay, I just bought a Metal Halide Ballast (I believe to be probe start) and the bulb illuminates with a slight yellowish color. What bulb should I buy to get a pure, or close to, white light for my projector?

can you please provide some more information about what ballast you bought and what lamp you are currently using ? links to places where you bought these items ?

generally you look for bulbs in the 5200-6500K range for "white light" bulbs...

cheers,
gs

I bought my kit here --> http://www.lightingcloseout.com/product_de...55&CategoryID=3

400W High Pressure Sodium Bulb Mogul (ED18) Base ANSI Ballast Type S51.
As for the bulb, it just says HPS-400W, on the box, the company is Proline Lighting.
Ive found this bulb online that might get the job done, what do you think? http://www.atlantalightbulbs.com/ecart/pg0827/23573.htm

Great ! Yes, what you purchased is a HPS (High Pressure Sodium) ballast and bulb. As you can tell, the temperature color from a sodium bulb is not well suited for projection. Yes, the link to the S400DD bulb is an excellent choice... it has a good color temperture (5200k), it can be run on the ballast you purchased (S51) and you will also be able to use it with the pro refelctor sold in the LL store. I'm afraid that the sodium bulb you bought was probably a waste, but live and learn is what I always say.

gs

Thanks a ton GS. If anyone else wants to buy my balast, heres a link to for the ballast alone, not including the yellow bulb or socket for just $69.95: http://www.lightingcloseout.com/product_de...56&CategoryID=3

quick question... I have a MH 400w bulb and wanted to know if it is safe to mount it horizontally.

Can you give more information on the bulb ? Make Model, etc.

cheers,
gs

Should I dont go above 400w. I thought to use a 600w, that is not good? Even if I want a brighter projection?

I have a 250w MH lamp in my box. When I first ran it, I noticed it kicked on to high power (brightness) after about 10 minutes. I'm using an icecap ballast. Now the lamp will be on low when I start it up, then it will jump to a 'high' that is really a 'medium' compared to what it was able to do when I first installed it (there are only a few hours of use on this bulb, btw).

Occasionally it will flash very bright - saturating the lcd panel and making the colors show up with beautiful vibrance, but it won't ever 'catch' at this level like it used to - it simply goes right back to the mid-level brightness. I'm wondering if I've installed the bulb incorrectly, because the wiring hasn't changed from the beginning. Does anyone have any experience with a problem like this? I'd really appreciate some guidance! thanks.

thanks!

I've been trying to figure out what make and model the LumenLab's 65k T15 is... specifically to figure out if it is compatible with the HPS S51 Ballast Kenshin has uncovered. $70 is a very nice price.

Any thoughts?

-space

The LL 65K T15 runs on an M59 ballast, which you should be able to find for less than $70 shipped. Hidirect.com is one place that seems to have decent prices on magnetic ballasts. There is always the LL electronic ballast too... nice thing about it is that it runs just about all 400W lamps... M59, M135/155, HQI & S51 HPS lamps...

cheers,
gs

I believe that there is also a fire hazard issue with an exploding metal halide bulb. If the do explode they will send very high temperature particals all over the inside of the box they are mounted in. Since most of the PJ enclosures are made of plywood or MDF this could be an issue. Some bulb manufacturers mention that the only safe enclosure is one made entirely of tempered glass.

Does anyone have any good recommendations for the bulb section of the enclosure? I was thinking of just covering the entire bulb section with sheet metal and putting a front piece of tempered glass and Lexan (not just Lexan which will ignite at temperatures above 800F). I'd also need some baffling between the fan and the light section to prevent the fan from sucking exploded bulb particles out of the box.

thanks,
jhc22

If I understand correct, the ARC tube is the pressure holder, and the outer jacket, usualy made of borosilicate glass, provides a stable thermal envirmoment for the arc tube.

But how much pressure does the outer jacket have to resist? I ask this since I scratched my outer jacket a bit and I wonder if there would be any breaking risk.

Why?

Why not above 400w? i want 600w since my antiglare and stuff are staying on, not risking another monitor