This little baby only lasts 50 hours, however it puts out 14,500 Lumens. Just out of curiousity, how would you drive this lamp? It is halogen, it runs at 36volts and it consumes 400W. Would you just need a transformer to step down 120v into 36volts?

PS. It's colour temp is 3400K, too low, but none the less I am curious

And then there is this one, 16,000Lumens, 3400k 50 hours.



Is it just a step down transformer that is required?

Yep just a transformer but it would need to be able to supply about 11amps.

DJ

Or a variac capable of supplying 11 amps.

These sort of lamps are used in OHPs and produce lots of heat

I was just curious about them. They are cheap, like $6 a lamp however they do only last 50hours.

I have these in my 3M 9550 overhead projector. They pop out after about 20 hours. Real annoying, but super small, and they generate a lot less heat than metal halide. They also look really red.

I have 250W 120V ENH lamps for $5 a piece. 175 hours doesn't sound to bad either. They also have the reflector built into each bulb.

I believe ENH and FXL lamps are essentially the same - only difference being 250W versus 410W.

So far I can't get very uniform illumination with the FXL - extremely hot spot in center - and I'm seeing bright "spokes" of light emanating outward from the center of the screen - without LCD, using just unsplit fresnels to test.

This is with a 317mm rear fresnel. It would appear that I'd need to back away the lamp even further to spread out the light more - although I did think about using a precondenser to pull in more light from outside the fresnels. Either way I need a longer FL fresnel, I believe.

And I don't feel I can eliminate the bright "spokes" of light - apparently coming from the "seams" inside the reflector between all the small facets. These seams might be creating dark "spokes" or there is an overlap of light taking place.

I'm going to give up on these little lamps, unless someone has any ideas???....

I wonder if anyone has gotten them to work well with a larger LCD (15"), versus a smaller one.

I think you *might* have been the only person to try.

Elkin has seen this problem too. It happends from having too small of an arc for the fresnel ring spacing. Dazzzla had a vary nice answer too. Making the spacing between the two fresnels can help and using .03mm pich fresnels will help.

Thanks AV. I think you may be right - because I hadn't seen those streaks until I tried projecting through the fresnels and triplet lens. I'll try spacing them out into a split configuration.

Are you suggesting using the finer pitch fresnels such as from 3DLens or elsewhere?

And it still likely won't solve the severe vignetting problem. The reality is these little lamps were designed for illuminating an OHP stage glass which is a smaller "square" than a 15" LCD.

Edit: Yep, moving the fresnels apart made the streaks go away.

Edit2: Vignetting is still an issue, but I decided I can live with it. Seems no worse than using a standard MH lamp and reflector without a precondenser.

Based on preliminary measurements I'm estimating I'll get about 200 lumens through the LCD. Not bad for a little $30 light engine (lamp/socket/diode). Yes, the life is short and replacement cost high...over time.

I believe I was getting about the same output from the 3M 9550 light engine in my first PJ - but I'll try to re-measure that the next time I get the chance.

im useing the 36v 400w got it out of an ohp it was in a reflector with a thick glass that magnifies the light
without it it wasnt very bright it does get hot but it does put out a great pic and color.

you can rewire an old microwave trans. to get the volts you need.
I did that for cnc machine.

http://www.lumenlab.com/forums/index.php?s...st&p=100555

Joe