Question about fans.

[Crazed_climber]

I have 2 fans in the back of my box behind the reflector, in oposite corners. The top left and bottom right. They are 80mm but they dont seem to be moving enough air. The box becomes over 100F after about an hour. Do you think changing them to 120mm would do the trick?
PS: I am using a big 400 watt MH.

 

[TravisBarker]

could u post a picture of your box?
in which direction does the air flow?
from bottom right to top left ?
2x 80mm fans should actually be enough

 

[Crazed_climber]

Heres the pictures
First one shows the 2 fans top one out bottom one in.

 

[Crazed_climber]

Heres the second one from the back (dont mind the tape)

 

[Crazed_climber]

Third shows the hole I cut for ventalation. (box is on feet so air can come in through bottom.)

 

[Crazed_climber]

Last shows a glass panel (to try and create a barrier between hot compartment and cool one.) and another vent on the bottom.

 

[noewjook]

I think the ventilation of the lamp will improve a lot by putting
the fans on the left and right side of the lampbox instead of the back .The reflector does not only concentrate the light to a surtain
direction but also the heath.The temperature on the back of your
projector might be much lower then the temperature on the first fresnel or glass because of the reflector which is very effective keeping the light AND the heath away from it.
So my advice is:
A fan on the left side of the bulb,cold air in,position low
A fan on the right side of the bulb,hot air out,position high

 

[Diragono]

I have 2 fans in the back of my box behind the reflector, in oposite corners. The top left and bottom right. They are 80mm but they dont seem to be moving enough air. The box becomes over 100F after about an hour. Do you think changing them to 120mm would do the trick?
PS: I am using a big 400 watt MH.

??? 2 80mm fans should be more than enough. I dunno if adding bigger ones will help so much. Is it possible to maybe just ADD a 120mm fan in there? If so, thats what I would do. But I would guess that something is wrong with your box.

 

[wylie-c]

120's should help cool it better, they tend to put out around twice as much as 80's if not more. Most 80's are around 30 cfm and most 120's are 70-80 cfm. I'm using 92mm in mine, just because Princess Auto had them on sale for 5 bucks each.

 

[ace3000_1]

120's should help cool it better, they tend to put out around twice as much as 80's if not more. Most 80's are around 30 cfm and most 120's are 70-80 cfm. I'm using 92mm in mine, just because Princess Auto had them on sale for 5 bucks each.

I agree on that note, they are also quieter, but with a properly designed projector for a 400w bulb 2x 80mm fans should be more then enough.

2 things to look out for, 1 is metalic areas, metal conducts heat, the more metal you have in there the more heat will get absorbed by the metal and in return the more heat will radiate from the metal Thats why yours gets hotter after time.

The second thing is where the light goes the heat will go, anything in its path will get hot and radiate the heat, it will also hold the heat as mentioned above. The more of a material or an object thats in the light path, the more heat you will get radiated/absorbed. Also the bigger somthing is the more heat it will hold/radiate and thats another reason why small bulbs are better then the big as we can not only controll the light to a confined area but also the heat, and thats why my light box works wonders.

At the end of the day, having a small volume of heat holding material, well directed light, compact enclosure to serve the heat source (arc), and a good clear airflow and you wont have any problems with heat, isolation, guidence and materials is the key.

Trev

 

[ace3000_1]

I have 2 fans in the back of my box behind the reflector, in oposite corners. The top left and bottom right.

In that design the 2 fans should be at the top of the enclosure as heat rises, they also should be sucking the air out and having 2 other fans on the bottom blowing air in would help considerably.

Trev

 

[Crazed_climber]

So ace you think I should add 2 more fans, a second one pulling air in at the bottom and a second one pushing air out of the top?

 

[Dazzzla]

Try making the glass that separates your pj smaller so there is a gap on top. Also make both fans extract. The way that you have it set this up is not quite correct. One or two things could be happening, for a push pull fan set up to work, it can only have two openings, yours has three. So if the rear chamber is not completely sealed, the airflow can't be controlled, you could actually be forcing hot air into the lcd compartment. If you have sealed the compartments then you only have one opening ventilating the lcd, it should have at least two. One at the top and one at the bottom and have air forced over it.

DJ