andy@rbdc.UUCP (Andy Pitts) (06/29/88)
I want to build a light hood for a marine aquarium. This requires intense light with a spectrum that closely matches the sun. The best results seem to be with metal halide arc lamps. Commercially available units sell for about $400.00 and use 2 175 watt lamps. I am a dialysis patient on a fixed income and am looking for a (much) less expensive way out. I have no problem making a unit but need some information on metal halide lights. I have had lots of experience in electronic design and construction, but my knowledge is badly lacking in this area. People in the local electric supply houses either don't know anything or don't want to talk to you unless you are a contractor and about to spend mega bucks. Therefore I very much need some kind soul on the net who can answer some question for me. 1) Mercury vapor street lights can be had at very reasonable prices. Can you use a 175 watt metal halide lamp with a 175 watt mercury vapor ballist? 2) If not, where can you get ballists and sockets without paying an arm and leg? 2a) Are high frequency ballists available at reasonable prices? If so where? 3) Can you mount these lamps in any position? 4) Is there any place where junk fixtures could be obtained cheap and the ballists salvaged. 5) What else do I need to know? Please direct follow ups to sci.electronics or respond to me directly. Any information would be much appreciated. Thanks in advance. -- Andy Pitts andy@rbdc.UUCP : "The giant Gorf was hit in one eye by a stone, mtune \ : and that eye turned inward so that it looked kd4nc !gladys!rbdc!andy : into his mind and he died of what he saw there." pacbell/ : --_The Forgotten Beast of Eld_, McKillip--
straka@ihlpf.ATT.COM (Straka) (06/30/88)
In article <523@rbdc.UUCP> andy@rbdc.UUCP (Andy Pitts) writes: > >I want to build a light hood for a marine aquarium. This requires intense >light with a spectrum that closely matches the sun. The best results seem >to be with metal halide arc lamps. Commercially available units sell for ... >1) Mercury vapor street lights can be had at very reasonable prices. Can As I recall, mercury vapor lamps have VERY strong spectral lines. This spectrum is VERY unrepresentative of sunlight. However, your typical fluorescent lamp (which uses a mercury vapor discharge, too) gives you a better shot at a wide spectrum because of the phoshor coating which fluoresces at some range of longer wavelengths. Try comparing standard cool white, warm white, and other specialty phosphor coatings. One of them or a combination of 2 of more different lamps may get you what you want. -- Rich Straka ihnp4!ihlpf!straka Avoid BrainDamage: MSDOS - just say no!
larry@kitty.UUCP (Larry Lippman) (07/01/88)
In article <523@rbdc.UUCP>, andy@rbdc.UUCP (Andy Pitts) writes: > I want to build a light hood for a marine aquarium. This requires intense > light with a spectrum that closely matches the sun. The best results seem > to be with metal halide arc lamps. Commercially available units sell for > about $400.00 and use 2 175 watt lamps. "Marine aquarium", indeed! Do you think that you can fool the Net with that story? Why, we all know that metal halide lamps are used indoors for only ONE purpose: to grow mary-wanna! For detailed technical information on the indoor application of metal halide lamps, just consult any issue of "High Times". :-) [serious technical questions and answers follow] > 1) Mercury vapor street lights can be had at very reasonable prices. Can > you use a 175 watt metal halide lamp with a 175 watt mercury vapor ballist? In general, no. Metal halide lamps, mercury vapor lamp and high pressure sodium vapor lamps are in a category known as High Intensity Discharge (HID) lamps HID lamps are in effect negative resistance devices and require current-limiting ballasts. In addition, HID lamps require starting voltages higher than line voltage (200 to 400 volts for metal halide and mercury vapor; 2,500 to 3,000 volts for high pressure sodium). Most ballasts are wound as autotransformers, and not only provide the necessary current-limiting, but provide a higher voltage for starting. In general, metal halide lamps require a HIGHER starting voltage than mercury vapor lamps; the voltage-current characteristics of metal halide lamps are also different than those of mercury vapor lamps. There is a very good possibility that an el-cheapo mercury vapor ballast will not ignite a metal halide lamp; even if it did, the ballast may overheat since it was never designed for metal halide use. > 2) If not, where can you get ballists and sockets without paying an arm and > leg? From a commercial electrical supply firm, such as Graybar Electric. Price is relative, however; I don't know of any source for "bargains" in this type of product. > 2a) Are high frequency ballists available at reasonable prices? If so where? As far as I know, no high frequency ballasts are available for HID lamps (I don't believe there is any reason to use high frequency in this type of application). > 3) Can you mount these lamps in any position? It depends upon the particular lamp; some lamps and fixtures ARE position-sensitive. > 4) Is there any place where junk fixtures could be obtained cheap and the > ballists salvaged. In the grand scheme of things, metal halide lamps are comparatively "new", as opposed to mercury vapor lamps; I would not expect to see much in the surplus area. > 5) What else do I need to know? You might wish to ask the people in alt.drugs. :-) <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|utzoo|uunet}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
piner@pur-phy (Richard Piner) (07/01/88)
In article <5164@ihlpf.ATT.COM> straka@ihlpf.UUCP (55223-Straka,R.J.) writes: >In article <523@rbdc.UUCP> andy@rbdc.UUCP (Andy Pitts) writes: >> >>I want to build a light hood for a marine aquarium. This requires intense >>light with a spectrum that closely matches the sun. The best results seem >>to be with metal halide arc lamps. Commercially available units sell for >... >>1) Mercury vapor street lights can be had at very reasonable prices. Can > >As I recall, mercury vapor lamps have VERY strong spectral lines. This >spectrum is VERY unrepresentative of sunlight. However, your typical >fluorescent lamp (which uses a mercury vapor discharge, too) gives you a >better shot at a wide spectrum because of the phoshor coating which >fluoresces at some range of longer wavelengths. Try comparing standard cool >white, warm white, and other specialty phosphor coatings. One of them or a >combination of 2 of more different lamps may get you what you want. >-- For what it's worth, I seem to recall a few years ago, seeing an ad for a flourescent lamp which worked in a standard fixure. But it was a "new and improved" model which put out a simulated solar spectrum. It was supposed to be used in offices which needed good lighting, such as a drafting room. It was made by GE or one of the other such companies. An good lighting store should be able to look through their catalogs and find the part number. They may even stock it. It didn't catch on here at Purdue because it wasn't cheap. Richard Piner
andy@rbdc.UUCP (Andy Pitts) (07/03/88)
In article <5164@ihlpf.ATT.COM>, straka@ihlpf.ATT.COM (Straka) writes: > In article <523@rbdc.UUCP> andy@rbdc.UUCP (Andy Pitts) writes: > > > >I want to build a light hood for a marine aquarium. This requires intense > >light with a spectrum that closely matches the sun. The best results seem > >to be with metal halide arc lamps. Commercially available units sell for > ... > >1) Mercury vapor street lights can be had at very reasonable prices. Can > > As I recall, mercury vapor lamps have VERY strong spectral lines. This > spectrum is VERY unrepresentative of sunlight. I know that mercury vapor lamps have a bad spectra for my purpose. However the question was, will 175 Watt metal halides (which have a very nice spectra) operate with a 175 watt mercury vapor ballast (which can be bought cheep). I have had one person tell me that the lamps are interchangable in some ballasts which are labeled for use with either type of lamp. A lot of old street lamps have ballasts with little or no labeling and I still would like to know if metal halides will work with these ballasts. I have had several people kindly offer suggestions about using flourescent lamps (and I may do that) and others wanting to know if I found out any thing. One person has even given me the numbers for the lamps and ballasts (Thanks, that will help), but so far no one has answered my questions. There must be someone on the net who knows something about metal halide lighting. Please direct follow ups to sci.electronics of reply to me directly. Thanks in advance. -- Andy Pitts andy@rbdc.UUCP : "The giant Gorf was hit in one eye by a stone, att \ : and that eye turned inward so that it looked kd4nc !gladys!rbdc!andy : into his mind and he died of what he saw there." pacbell/ : --_The Forgotten Beast of Eld_, McKillip--
andy@rbdc.UUCP (Andy Pitts) (07/04/88)
In article <2589@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes: >In article <523@rbdc.UUCP>, andy@rbdc.UUCP (Andy Pitts) writes: >> I want to build a light hood for a marine aquarium. This requires intense >> light with a spectrum that closely matches the sun. The best results seem >> to be with metal halide arc lamps. Commercially available units sell for >> about $400.00 and use 2 175 watt lamps. > > "Marine aquarium", indeed! Do you think that you can fool the Net >with that story? Why, we all know that metal halide lamps are used indoors >for only ONE purpose: to grow mary-wanna! Believe it or not, I really am using this for a marine aquarium (David Dalton will verify that). I have a 55 gal tank and am building a trickle filter. I have had a marine system running for about 5 years and am doing improvements. Several people have suggested "High Times". It is strange, I was not aware of the publication (which is really weird because I worked at a drug clinic for about 2 years in the late 60's) I may have to check it out (1/2 :-) ). Thanks for the information. It was just what I needed. -- Andy Pitts andy@rbdc.UUCP : "The giant Gorf was hit in one eye by a stone, att \ : and that eye turned inward so that it looked kd4nc !gladys!rbdc!andy : into his mind and he died of what he saw there." pacbell/ : --_The Forgotten Beast of Eld_, McKillip--
learn@igloo.UUCP (william vajk) (07/05/88)
In article <525@rbdc.UUCP> Andy Pitts writes: > have had one person tell me that the lamps are interchangable in some ballasts > which are labeled for use with either type of lamp. A lot of old street lamps > have ballasts with little or no labeling and I still would like to know > if metal halides will work with these ballasts. The metal halide ballasts cost a lot more than the mercury vapor variety because of design considerations. The price of those ballasts usually has a lot to do with this sort of question which arises from time to time in my business, electrical contracting. To be brief, any ballast which might handle both sorts of lamps always does so at the additional cost of shortened bulb life unless you have paid a higher price for a ballast with multiple windings especially designed for multiple purposes. I've heard of such ballasts, but have not found any in my collection of catalogs, and have never had occasion to need one. If you're technically proficient at design, you might attempt to create a solid state ballast, otherwise you'll have to bite the bullet and pay for the standard unit designed for use with metal halide lamps. I further recommend that you acquire a complete unit with appropriate shielding for RF considerations. These bulbs are of the arc variety. Bill Vajk learn@igloo
rsd@sei.cmu.edu (Richard S D'Ippolito) (07/07/88)
In article <529@rbdc.UUCP> andy@rbdc.UUCP (Andy Pitts) writes: >Believe it or not, I really am using this for a marine aquarium (David Dalton >will verify that). I have a 55 gal tank and am building a trickle filter. I >have had a marine system running for about 5 years and am doing >improvements. What intensity (in footcandles) do you need? It might be much cheaper and produce less heat near the aquarium to use several fluorescents ( "daylight" and/or "grow lamps" ). You will also have a problem with the concentration of light -- the fluorescents will have a larger radiation surface so that their intensity will be less for a given total flux. The other lamps may produce damaging amounts of UV at close range, which might deteriorate rubber and plastic ( and 'burn' the fish!). In other words, are you paying as much attention to the quality of the light source? Rich