Hello, this is my first projector and i am having two problems. 1:i am using a 500 watt halogen lamp and it is very very hot. 2:it is also really dark even in the middle.
Please suggest other lamps or how to solve this. I am using tempered glass and i am not using a fan because i am sure that the fan won't make a difference because it VERY hot i really can't describe how hot it is.
Thank you in advance.
Full Version: 1st PJ
Your problem is (mostly) the halogen lamp.
For all practical intents and purposes, wattage=heat.
While there is some dissipation of light in that wattage as well, no matter what the light engine, a large portion of that light gets dissipated as pure heat.
However, even if it were not so, the amount of generated light that manages to get out of the front of the projector is pretty low, with the rest of it ending up as... You guessed it. Heat. So, for all intents and purposes, wattage=heat.
Now for light, your 500W halogen produces maybe 20 lumens/watt, so you're getting about 10,000 raw lumens. If your lamp filament is more than about an inch long, then you can only use a portion of those raw lumens, too.
A MH lamp, on the other hand, produces about 80 lumens/watt (With some going as high as 110 lumens/watt, but we'll take the low end, for comparison.) So a 250W MH lamp will produce 20,000 lumens. Right off the crack of the bat, we've got twice the raw lumens, for 1/2 the heat. Make that a 400W lamp and you've got 32,000 lumens. The MH lamp will also have a smaller lamp arc than the average halogen, which makes it mor useable for projection.
As for cooling... Use a fan!!!
I can't stress enough how important this is. It's not to cool the lamp. We really don't much care how hot the lamp gets, it'll deal. We do, however need to cool the LCD. The LCD has a max operating temperature of about 45 deg C. If you let it get much hotter than that, it will fail.
For all practical intents and purposes, wattage=heat.
While there is some dissipation of light in that wattage as well, no matter what the light engine, a large portion of that light gets dissipated as pure heat.
However, even if it were not so, the amount of generated light that manages to get out of the front of the projector is pretty low, with the rest of it ending up as... You guessed it. Heat. So, for all intents and purposes, wattage=heat.
Now for light, your 500W halogen produces maybe 20 lumens/watt, so you're getting about 10,000 raw lumens. If your lamp filament is more than about an inch long, then you can only use a portion of those raw lumens, too.
A MH lamp, on the other hand, produces about 80 lumens/watt (With some going as high as 110 lumens/watt, but we'll take the low end, for comparison.) So a 250W MH lamp will produce 20,000 lumens. Right off the crack of the bat, we've got twice the raw lumens, for 1/2 the heat. Make that a 400W lamp and you've got 32,000 lumens. The MH lamp will also have a smaller lamp arc than the average halogen, which makes it mor useable for projection.
As for cooling... Use a fan!!!
I can't stress enough how important this is. It's not to cool the lamp. We really don't much care how hot the lamp gets, it'll deal. We do, however need to cool the LCD. The LCD has a max operating temperature of about 45 deg C. If you let it get much hotter than that, it will fail.
QUOTE (SupraGuy @ Sep 4 2009, 03:43 AM) 
Your problem is (mostly) the halogen lamp.
For all practical intents and purposes, wattage=heat.
While there is some dissipation of light in that wattage as well, no matter what the light engine, a large portion of that light gets dissipated as pure heat.
However, even if it were not so, the amount of generated light that manages to get out of the front of the projector is pretty low, with the rest of it ending up as... You guessed it. Heat. So, for all intents and purposes, wattage=heat.
Now for light, your 500W halogen produces maybe 20 lumens/watt, so you're getting about 10,000 raw lumens. If your lamp filament is more than about an inch long, then you can only use a portion of those raw lumens, too.
A MH lamp, on the other hand, produces about 80 lumens/watt (With some going as high as 110 lumens/watt, but we'll take the low end, for comparison.) So a 250W MH lamp will produce 20,000 lumens. Right off the crack of the bat, we've got twice the raw lumens, for 1/2 the heat. Make that a 400W lamp and you've got 32,000 lumens. The MH lamp will also have a smaller lamp arc than the average halogen, which makes it mor useable for projection.
As for cooling... Use a fan!!!
I can't stress enough how important this is. It's not to cool the lamp. We really don't much care how hot the lamp gets, it'll deal. We do, however need to cool the LCD. The LCD has a max operating temperature of about 45 deg C. If you let it get much hotter than that, it will fail.
For all practical intents and purposes, wattage=heat.
While there is some dissipation of light in that wattage as well, no matter what the light engine, a large portion of that light gets dissipated as pure heat.
However, even if it were not so, the amount of generated light that manages to get out of the front of the projector is pretty low, with the rest of it ending up as... You guessed it. Heat. So, for all intents and purposes, wattage=heat.
Now for light, your 500W halogen produces maybe 20 lumens/watt, so you're getting about 10,000 raw lumens. If your lamp filament is more than about an inch long, then you can only use a portion of those raw lumens, too.
A MH lamp, on the other hand, produces about 80 lumens/watt (With some going as high as 110 lumens/watt, but we'll take the low end, for comparison.) So a 250W MH lamp will produce 20,000 lumens. Right off the crack of the bat, we've got twice the raw lumens, for 1/2 the heat. Make that a 400W lamp and you've got 32,000 lumens. The MH lamp will also have a smaller lamp arc than the average halogen, which makes it mor useable for projection.
As for cooling... Use a fan!!!
I can't stress enough how important this is. It's not to cool the lamp. We really don't much care how hot the lamp gets, it'll deal. We do, however need to cool the LCD. The LCD has a max operating temperature of about 45 deg C. If you let it get much hotter than that, it will fail.
Thank you very much supraguy this was very helpful. And i would also like to ask about the tempered glass. Is it enough to protect the LCD from UV rays?.
thank you again.
Tempered glass does not stop UV. You will need either a UV film, or else something like Lexan XL10, which has UF protection built in.
The AG layer on the LCD (Which is facing the lamp in a straight-through build) will also have UV protection in it, but you will find that the UV will damage the fresnel lenses over time.
The AG layer on the LCD (Which is facing the lamp in a straight-through build) will also have UV protection in it, but you will find that the UV will damage the fresnel lenses over time.
QUOTE (SupraGuy @ Sep 4 2009, 10:40 AM)
Tempered glass does not stop UV. You will need either a UV film, or else something like Lexan XL10, which has UF protection built in.
The AG layer on the LCD (Which is facing the lamp in a straight-through build) will also have UV protection in it, but you will find that the UV will damage the fresnel lenses over time.
The AG layer on the LCD (Which is facing the lamp in a straight-through build) will also have UV protection in it, but you will find that the UV will damage the fresnel lenses over time.
hello, thank you for your fast reply. I am going out today to buy a metal halide lamp and ballsat,ignitor etc...
and i am also going to buy either lexan or a UV film.
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