Could also ramp up the fan rpm at shutdown for faster cooling.

the max cfm is 100 and I found the volume acceptable at around 80 (assuming the knob has a linear relation to the speed) good call on the shutdown speed. I also didn't put my fan on shock mounts and I accidentally got a bit of paint on the fins which I noticed changed the sound. The way I put my box together I'd really rather not take the fan out again (it's glued in there) but the entire time I was building this one I was thinking about "what I'd do next time" so I think there's another pj in my future although I'm very happy with the image results from this one.

awhile back i saw a fan(blower) that looked like a fishtank Filter. It looked like the prop in a 6" fishtank pump. if anyonw knows the name or where to get them i would appreciate the help. I tried to google search but dont know the correct name.

Edited: looks just like this but bigger


P.S. LUMENLAB RULES!!!!!

Well that's the Evercool PCAC. It comes in black too, but I've not seen a bigger one.

There is one in Finding Nemo, called the aqua 2000 or something like that
DJ

lol I would suggest just getting the PCAC. VERY quiet.

Just curious,

Just read somewhere that there are different sides to a lexan panel and that if the wrong one is facing the lamp, it might turn milky white. Must not have read that on the lexan itself during my 4am box building haze. Is there a way to tell once the paper has been removed from a lexan sheet which side is which?

This is probably a really stupid question. Is "switch bridge" an actual component you can buy or is it just words to describe wires connecting the DPST and the thermo switch together? I'm refering to Brain's diagram on page 2 of the thread. My first post and apologies if the diagram didn't get attached properly.

It is the method of wiring the switch, not a component. The switch being a double pole is actually two switches together operated by a single lever. The side to the lamp is controlled solely by the switch, but the fan side has a bridge across it that is controlled by the thermostat as well as the switch. When the switch is initially turned on, the lamp and fan are powered. The bridge will not close until the thermostat has warmed up. Turning the switch off anytime after that will keep the fan(s) on untill the projector has cooled and the thermostat opens.

Speaking of "don't melt that plastic"...

If I use plastic channel to frame the sides of my Lexan/fresnel sandwich, is there a chance the heat from the lamp will melt the channel? I definitely don't want melty plastic goo all over my fresnel.

i wouldn't risk it on the lexan itself unless it was also made of lexan, other then that the rest of the components (after that heat shield) should be fine i would think with regular (thick) polycarbonate as rails, but that's just my opinion.

I don't know electronic schematics that well, but I have a friend that does. I was hoping someone could draw up the ckt in two configurations--if it matters: One with the thermostat operating a12vdc fan, and one with the thermostat operating a 120v fan (both in picture terms, not in schematic form especially the switch bridge.)

Also, I saw two different thermal switches, one small little thing and the other an attic fan thermostat. Are these basically the same thing?

I'm ready to start this thing and I'm being held up by this fan wiring scenario. Do I go thermostat, or Timer Delay? and the same issue keeps coming up: How do I wire two circuits to the same switch, with one staying on after the switch is thrown open for cooling after?

Hope my Q's make sense...:confused:
Steamer

After careful re-consideration of this thread, I think I understand my Q's about the switch bridge, and therein my single switch problem. If I wire my fan circuit directly to the switch--which must be DPST, the fans will operate as long as the switch is on. But, if I run the thermal switch getting its power not from the single switch, but directly from the source, I can have a "separate" circuit for cooling after, the thermostat working like a relay. Am I on the right track with these thoughts?

Steamer

P.S. all those other switches and crazy ideas I had schemed up are going right back to the electronics store!

Here's a schematic that I drew up (sorry my ms paint skills are horrible) anyways this is a marriage of rcl's schematic and brain's "attic thermostat" schematic. I did my best to join the two together. One dpst switch will replace the two spst switches. I also incorporated a terminal strip, not really required, but It sure keeps things cleen inside, not to mention a little safer than twisting wires together. In this schematic when the power is switched on, the lcd, fan, and bulb/ballast will all get power. This keeps the bulb from powering up without the fan on. When the switch is turned off, power will still be supplied to the thermostat which will pass power on to the fan until the temp drops to a preselected value and the thermostat opens the circuit. Brain, what do you think? I'm not an electrical engineer but I think this should work

Thanx a 'zillion'! That is exactly what I needed. Boy, you guys sre sll right, I don't care what they said...!

But I have 12v fans and a single 12v power supply for the lcd and fans. Is there a way to wire this up on one switch with a setup like this?

Steamer

EDIT- I think I found my answer n the thread regarding Lamp Wiring ,Timers, and Other Control Circuits. However, if anyone cares to clarify, please feel free to do so.

hey steamer, here's the solution to your problem i think. basically what I'd do is splice into the 12v output from the lcd power supply. connect the negative to the fan directly and the positive to the terminal post. Now you have wiring for a 12v fan!!

Is that really a good idea?

I don't know how the LCD works but fan creats lots of noise on the line... I would think the LCD power supply does a lot of filtering to make sure nothing weird gets on the 12VDC line.

If your going to do that I would suggest throwing in some capaciters to keep the Fan away from the actual lines of the LCD.

Wait... that diagram wont work.

The thermostat won't get any power once the power is turned off. Which means no power to fan even if the thermostat is working

That all electronics site that someone has linked here has a tons of neat little itmes, one of which i picked up was a nice rectangular (slim PC probably) 120 to 12 converter, $3.50 (minimum $6shipping, so buy the other electronics you might need from there at the same time), its enclosed and very neat in design (about 1.2"x1"x7"). it only puts out .6A at 12V (couple amps at 5), but that's more then enough to juice for fans and the like, not to mention it has built in protections.

My .02 on the temp switch. I had been planning on that as well for the past few months of research. Mainly because I was going to do a cooling slot at the bottom and this would cause a trap at the top where hot air could congregate.

I changed to a top vent as called for in the standard plans. Any hot air will release naturally with the top vent.

With regards to cooling the light chamber for five minutes or so after use - - I tell you what, after a movie it will take me more than 5 or 10 minutes just to clean up the popcorn and juice boxes off of the floor from my three son's.

I'll have two power switched, one for the fan and the other for the LCD and light, wired so that the LCD and lamp switch remains dead until the fan switch is on. In other words, the lcd and lamp power is slaved to the fan.

PIC showing just hot

John

the thermostat gets power through the terminal bar when the switch is turned off. the paralell lines on the bar are to show wich posts are linked together by a metal strip.

great idea jersey, now it's impossible to the light on without the fan, just make sure that someone doesnt turn off the fan prematurely

I thought I could try something like this. I figure if I could hardwire the 12V PSU to the mains on a terminal block (for neatness) and then to the secondary pole of the DPST I could isolate the LCD from the fan. (Or something to that effect.) If anybody can see my aim but sees any areas that need to be corrected, feel free to edit to make it work.

Steamer

Schematic edited to show Icecap Ballast - not M59

Having inductive circuits on your regulated LCD DC power supply is not a good idea. Leave the regulated supply for your panel alone. Add another 12v supply for your fans.

Also, what lamp are you using that has FC2 bases and a M59 ballast?

Sorry,

It's an Icecap ballast. I just forgot to delete M59 from the copied schematic. I'm using an HQI 250W on a 7" Lilliput design.

So if I use the original wall wart for the Lilliput and this new 12V supply for My fans I could do this thermal setup?
BTW, How is it inductive, and why is this bad?

Steamer

The Fan makes it inductive.

Its possible to use the same power, but I think its easer to just get a AC adapter and hook the fan up... Its hard to tell what the fan can do to the 12VDC supply for your LCD.



--- Edit forgot to comment on your design...

I think you have a extra line connecting the thermostat power to the LCD. Your design will keep the LCD on with the fan. Besides this and what Brain said, I think it looks good

Isn't there a way to inhibit the fan's inductance? I took a couple of basic electronics classes several years ago, and currently I don't do much with electronics so I could be a little off base on this.




I wasn't sure how to show the terminal blocks and their correct orientation. Basically, each top lug is connected via a metallic band to each corresponding bottom lug. I drew that line from the thermo between the strips because I was running out of space and I didn't have anywhere else to put it. It is only connected at the lug though. In other words, it doesn't make contact with the wiring from LCD. I'll try to edit it to show what I mean.

Steamer

Something like this:

I've modified your image to show what I was talking about

Yes, there is a way to reduce the fan's inductance. You would use a capacitor to absorbe any inductance the fan creates.

Capacitor would do the job, but the problem is the fan might not run at 100%.

I think this will work for most 12VDC Computer fans.

I'm not sure what C should be at the moment. I sorta remember seeing this circuit built into the evercool, but I might be wrong. I'll check when I get home.

I don't know if its a big deal but the Capacitor will drop the voltage so it will not run the fan at 100% (12V to 11.5V or so). Also watch how much Amp the fan uses and the lcd wants if you use this.

Removed image since its wrong...

Could you explain to me the symbols? I don't read actual schematics right. (I think I said this once, but I think it was in the timer thread)

Steamer

M = motor (Fan)
C = capacitor
Q = Transistor (NPN)
R = Resistor

Thanx.

And all this goes where that little slash is that you added in my wiring diagram? Oh, and let me know about the evercool. I might have to get one of these. Don't worry about the amps. I have a 12v supply that puts out about 5 amps that should cover the Lilliput and a couple of fans.

Oops, I just noticed that I stuck a NPN transistor in there instead of a PNP... I'll fix it and upload with more detailed information later... just letting you know that its wrong

I'll test the circuit to make sure it works before i post next time.

Steamer,

I'm going to post in
"Lamp Wiring, Timers and Other Control Circuits"
http://www.lumenlab.com/forums/index.php?s...pic=1007&st=200
Since it seems like a better place to post this stuff.

Well I've read through lot of the post on the message board now and there is a lot of argument about pushing air in and pulling air out.

Here are my findings from various sources

Pushing air in system is called a high pressure system and a method used in very tight box (eg. web server). This method works by creating a higher pressure on the inside of the case, forcing air out. This also prevents dust from getting in from the small holes you have in the projector, so it is dust free

Pulling air out of system is called a low pressure system. This system will pull air into the system for cooling. This is the lumen lab system. According to many sources, this is the best way to cool. The only problem is that it is hard to design a good venting for this to work properly. In our case Brain figured out the best venting for us

In both case, for max. cooling you are supposed to have a opening that are equal to the fan vent.

Lot of webpage also talk about the combination of the 2 system. Pushing air in and out at the same time can cause unstability and the result is very hard to perdict. They suggest using a software to calculate the air flow. I guess trial and error is the only way to really find a good combination.

I did lots of research on fan types so I'll post it here as well.

From what I read I found 3 major types of fan. Axial Fans (PC fan), Centrifugical Blower (Hair drier), and the Cross Flow Blowers (air curtain, evercool).

Axial Fans - good for everything. High pressure or Low pressure. Mid range for air flow and air pressure.
Centrifugical Blower - Good for spot cooling... Not good for pushing or pulling air into the system. You would use this fan inside the case to spot cool a area that gets too hot. Small amount of air flow but high pressure. Some high end graphic card uses this fan to push air through the heat sink.
Cross Flow Blowers - Only good for low pressure setup. Large amount of air flow but low pressure.

High pressure = More Noise

Wow, this is a long post and hope this was the right place to post this
Thanks

Does anyone know the temperature of say a piece metal about 2-4 “ from the ark of a lamp? The reason I need to know is I would like to use RTV silicon on an aluminium enclosure around the lamp, with no metal to metal contact. Normal silicon emits toxic fumes above about 116° C, the RTV silicon is rated about 316° C but I’m unsure if it emits toxic fumes. If the aluminium goes beyond this temp I think I’ll have to use something else, any ideas?

DJ

Allthumbs posted some temp tests on this thread.

http://www.lumenlab.com/forums/index.php?showtopic=1515&hl=

I think that RTV will be OK. I plan to use it if necessary in the lamp area.

Thankyou DeathRay64, I did a search but somehow missed that one.

DJ

If anyone is interested, I've done some tests today with RTV and it appears to be able to stand the heat from a 500W QI lamp with a small amount of fan cooling. The test set up I used was a work light with the front glass removed and half of the font covered with aluminium and another sheet of aluminium on top of it separated by about 5mm of RTV in a couple of spots. After an hour with the fan blowing across it, I can place my hand on it. I also tried it with small metal nuts separating it but the heat simply conducts straight though, RTV is much better.
This might be useful to those who are worried about their ballasts getting to hot in the LL projector.

DJ

The turbine/centrifigal blower sounds like a neat idea. If their specs are to be believed then they're real quiet.

I may use this particular evercool blower right here. (Use coupon code PRICEWATCH for free shipping). It hits 100cfm @ 23db and its speed is manually adjustable.



I'll cut a notch in the middle of my box's back panel, just over where my ballast may be placed. I may just leave the ballast out of the box but i may still incorporate the above cooler. It seems to be a good combo of high cfm's and low decibals.

the PCAC, its quite popular here, i have 2, although i accidentally ordered the see through ones, thought when it said blue that it would be solid blue... oh well, nothing a little paint won't fix.

Here is a link on why fans are loud and some ways to bring down the dba's. It for computers but good info. especially for those who have cool stamped grills.

http://www.7volts.com/quiet.htm

I've got one Evercool on my projector, and I wouldn't call it quiet... the little things hums along at max speed, and it's noticeable during any quiet sections of movies... but I still have a lot of work to do with remounting it and isolating it from the box and such... the box definitely acts as a resonator. I've also recently changed the way my tempered glass is mounted in there, and I think I could get away with runnign the fan at partial speed... tests will tell.

I'm particularly sensitive to this type of fan noise... it's one of the reasons I really like my Mac G5 over most PC's and even the older G4 and G3 Macs... the G5 towers are much quieter. I'm guessing this is because the G5's use nine fans running at slow speeds instead of one or two fans running at high speeds... there is a lesson to be learned here... I think I might invest in a couple more Evercools and just run them all at lower RPM's.

My question, though is this... has anyone tried to cool the box using convection only? Anyone remember the old Mac SE/30's from the 80's? There was one company out there that sold a tall "chimney" that fit over the top of your machine and causes an "updraft" because of convection. Supposedly, it pulled cool air in the bottom of the machine, and helped cool the box. Obviously, we're dealing with a lot more heat with our 400W MH bulbs, but I'm curious if anyone has tried or succeeded in cooling the box without fans?

Thanks,
-N.

StorminN,

I'm using 2 of the Evercools in my PJ and have found the same thing: they are LOUD!

They work beautifully and are almost silent until you put the lid on the box and then all hell beaks loose! They sound like a jet engine. I've tried everything: added support screws, silicone around the edges, cardboard pieces under the edges to relieve some of the mechanical noise.

They're still bothersome to me.

The problem likely is that you have too much FAN and not enough inlet area. If the volume gets louder with the lid on its likely they are starved for air. This will give you that stalled turbine sound. all the fans in the world won't pull more air through a small inlet slot. I think your just stalling the blades and then they whine.

Kirk

I've opened up my air inlet slot as big as I'd feel comfortable - it's at 15mm right now. That's after opening up by a few mm's a couple days ago.

If I turn the fans down to the point where they aren't whining, the box doesn't stay cool enough.

I noticed the same sort of thing with my Evercool... it definitely changes pitch depending upon how much air it can pull... or push! Have you noticed that when the fan's running and you put a hand near the exhaust (blocking it a bit), the sound changes?

My inlet slot is probably close to 25mm, and I cleaned up some of the airway path and it got quieter... you might make sure your air path is not too restricted, or you might open your slot or cut an additional slot somewhere else?

I plan on making an angled cover for my slot, to deflect the light that spills from it... for the time being, I'm using some opaque metal tape to serve that purpose...

-N.

Here's a current pic of my projector...

The partition closest to the bulb has tempered glass mounted on the rear side... the tempered glass is still in the metal frame it came in from the floodlight fixture I scavenged the bulb, ballast, and mogul socket from. I've mounted the Lumenlab plastic UV filter on the front side of this partition. This partition has a gap at the bottom that's maybe 50mm tall and 300mm wide.

The next partition to the right has the rear fresnel mounted to its front side, and at the bottom it has a gap that's about 50mm tall and 300mm wide.

The partition to the right of the rear fresnel has the LCD mounted to it. It has no gap at the bottom. The foam at the top of this partition and at the top of the rear fresnel partition seal them against the lid when it's closed, and bridge the gap in the lid. The white wire is for the temperature probe of a digital thermometer...



When I first saw the diagrams of these projectors, I didn't understand why people would mount the tempered glass close to LCD and far from the bulb... to me it seemed like this would just invite more heat to reach the LCD. That, combined with the size of glass that I had to work with, caused me to mount the glass close to the bulb and further from the LCD.

Watching two movies last night, with one Evercool fan on max RPM's, the temperature between the rear fresnel and the LCD never got above 74F.

My next step is to install two more Evercools so I can run all three at lower RPM's, which will hopefully be quieter than one at max RPM.

-N.

Has anybody seen or have any experience with this:

http://www.sundialmicro.com/cgi-bin/sundial/stfb01.html

Seems like an alternative to running multiple Evercool PCACs.

I was going to pick a few of these up 115 volt Tangential blowers to see how they worked out. They are only $9 each