Hlias Posted April 3, 2014 Share Posted April 3, 2014 Good morning guys, I need your experience, your advices! I am upgrading an old scanner lately. I will install an MSD/2 250 Watt bulb and since I have some ballasts in my storage place, I am thinking of using them in an unusual way. My questions are: - Generally, can I use a metal halide lamp with a ballast that has characteristics above the lamp's requirements? In my case, I have a ballast that used in an Osram HTI 400 W/24, so I wonder if this will work with the MSD. I am sceptic about that, because the HTI's rated voltage is 55Volt and the MSD's is 95V. But, what do you think? Unfortunately, I don't know more details about this ballast, there are no information on it. - Can I use two ballasts in parallel mode? I have two Eaglerise ballasts for 150Watt lamp and I believe that using them with parallel connection, I will make the circuit work. This year, I saw for the first time a fixture which used two 250W ballasts in parallel connection. The fixture used an MSR 400 lamp. I was actually very surprised seeing this! You can see the installation of these ballasts inside the fixture. Here's a picture of it : http://i135.photobucket.com/albums/q124/ILIAS_02/eurocolour.jpg?t=1396505752 So, what do you think guys? Is it safe to use ballast with these ways?? Cheers! :) Link to comment Share on other sites More sharing options...
DrV Posted April 3, 2014 Share Posted April 3, 2014 No no no! <tounge-in-cheek>Mods - please can you move this thread to the pyrotechnics forum where it belongs!</tounge-in-cheek> Dave Link to comment Share on other sites More sharing options...
csg Posted April 3, 2014 Share Posted April 3, 2014 Is this a late april fool windup? I mean, come on, surely you can work out your own answers from the statements you have given... personally, if it were me, I'd leave this to someone who knows what they are doing. And thats not you. Link to comment Share on other sites More sharing options...
Hlias Posted April 3, 2014 Author Share Posted April 3, 2014 The ironic attitude and criticism wasn't necessary guys... I got the point. Thank's for replying anyway Link to comment Share on other sites More sharing options...
Brian Posted April 3, 2014 Share Posted April 3, 2014 ...can I use a metal halide lamp with a ballast that has characteristics above the lamp's requirements? No. Ballasts should always be matched to the lamp they are running. To do otherwise risks running the lamps outside their voltage/current/power rating and 'Bad Things Happen' © ...Can I use two ballasts in parallel mode? Yes. BUT. Two parallel inductors of equal inductance, situated so that their magnetic fields don't interact, will have half the inductance of a single inductor. So you can calculate the effect the parallel connection will have. HOWEVER, as I said above, Ballasts need to be matched to the lamp type and rating so it's not as simple as picking random Ballasts off the shelf. What you have to do is go back to basics and calculate the value of Ballast you need to suit your lamp. This calculation has normally been done for you by the Ballast manufacturer which is why they are usually marked with the lamp type they suit as opposed to any electrical values. Link to comment Share on other sites More sharing options...
Jivemaster Posted April 3, 2014 Share Posted April 3, 2014 The lamp, the starter and the ballast need to be suited to each other. Bad things happen when something doesn't work with the others. ALSO please remember that the failure mode of an ill treated discharge lamp is to explode, sending out fragments of glass shrapnel. This is part of the reason why lanterns intended for discharge lamps have robust cases. Link to comment Share on other sites More sharing options...
Hlias Posted April 3, 2014 Author Share Posted April 3, 2014 Thanks guys for your replies! I have unfortunately experienced a lamp explosion and damages in one of my fixtures. It was an Osram which failed after only 700 working hours. Since I saw this old colour changer with the two ballasts, I got these ideas and the curiosity to see if the parallel connection is actually working in some ways. --Also the fixture with the 2x250W ballast and MSR400 was actually working and it was an officially made fixture, not a custom one--. But I wanted to hear the advices from experienced professionals before trying anything. Thanks for making that clear to me :) Friendly regards, Elias Link to comment Share on other sites More sharing options...
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