Hi,
You mean you want to see a pic, or you want me to send you one?
Peter
Search found 135 matches
- Fri Jan 05, 2007 8:32 am
- Forum: Fans and Control
- Topic: The 4-pin PWM fan specification document
- Replies: 26
- Views: 69776
- Fri Jan 05, 2007 7:34 am
- Forum: Fans and Control
- Topic: How Low Can You Go? (rpm-wise)
- Replies: 20
- Views: 8357
- Fri Jan 05, 2007 5:35 am
- Forum: Fans and Control
- Topic: How Low Can You Go? (rpm-wise)
- Replies: 20
- Views: 8357
- Thu Jan 04, 2007 12:22 pm
- Forum: Fans and Control
- Topic: The 4-pin PWM fan specification document
- Replies: 26
- Views: 69776
Hi, We have tested the prototypes, and we are using them on machines that I build, while we organize larger volume production. It is a PWM to DC converter. The input to the circuit is PWM (4 pin) and the output is ordinary 3pin with the power voltage between 3V and 12V depending the PWM input. There...
- Wed Jan 03, 2007 1:23 pm
- Forum: Fans and Control
- Topic: The 4-pin PWM fan specification document
- Replies: 26
- Views: 69776
- Wed Jan 03, 2007 1:19 pm
- Forum: Deals, Vendors and Classifieds
- Topic: FS: PWM->analog Voltage Controller Circuit for pumps/fans
- Replies: 17
- Views: 23406
- Tue Jan 02, 2007 6:57 am
- Forum: Fans and Control
- Topic: "250mm" fans vs 120mm: the physics, math, tables &
- Replies: 13
- Views: 5499
Hi, I completely agree that thre must be tip vortices and that the flow cannot ne entirely laminar. But by "laminar flow" I meant tht the flow over the baldes was largly laminar, with turbulence confined to the boundary layer and teh tip vortices. That's certaily what you get on the sail of a yacht,...
- Tue Jan 02, 2007 5:12 am
- Forum: Fans and Control
- Topic: "250mm" fans vs 120mm: the physics, math, tables &
- Replies: 13
- Views: 5499
Hi, Excellent, thanks. So that's energy proportional to specific gravity of air times velocity cubed. Seems intuitive now, and if experimental evidence confirm it as well... I'm still concernrd that the noise ~ power bit is only true within a limited envelope of conditions - something like subsonic ...
- Mon Jan 01, 2007 3:24 pm
- Forum: Fans and Control
- Topic: "250mm" fans vs 120mm: the physics, math, tables &
- Replies: 13
- Views: 5499
Hi, I'm simply trying to understand. There is no way that energy is proportional to mass times velocity cubed because energy it is in fact proportional to mass times velocity squared. The mass of the air colum may itself be proportional to the velocity, and I'm intirely happy with the idea that tota...
- Mon Jan 01, 2007 2:47 am
- Forum: Fans and Control
- Topic: "250mm" fans vs 120mm: the physics, math, tables &
- Replies: 13
- Views: 5499
Hi, 1. The energy of a moving column of air is equal to M*V^3, where M is the mass of air and V is its velocity. 2. Acoustic noise is proportional to the energy. 1. I'd be prepared to beleive that the energy was SxV*3 (where S is the specific graviity of air) as the mass of air passing through the f...
- Fri Dec 29, 2006 6:13 am
- Forum: Fans and Control
- Topic: Restriction?
- Replies: 20
- Views: 7924
- Fri Dec 29, 2006 2:41 am
- Forum: Fans and Control
- Topic: Restriction?
- Replies: 20
- Views: 7924
Hi, I'd have to say that that's a valid, but very insensitive test. The probelm is that the CPU temp is only reported to 1C. Let's look at the numbers: The CPU generates a constant amount of heat, so the total rise in the air temp flowing through the cooler multiplied by the air flow through the coo...
- Wed Dec 27, 2006 7:57 am
- Forum: Fans and Control
- Topic: blowers vs fans
- Replies: 7
- Views: 3951
- Wed Dec 27, 2006 4:58 am
- Forum: Fans and Control
- Topic: Calling All Good Fans!
- Replies: 143
- Views: 313775
Hi, I've just recieved a batch of GlobalWin 120mm fans with ceramic bearings. The bearings are suitable for high(er) temperature work - i.e CPU cooling fans. There is definately much less noise coming from the bearings compared to say the Asaka Amber; and also much less commutator vibration at low s...
- Wed Dec 27, 2006 4:24 am
- Forum: Fans and Control
- Topic: blowers vs fans
- Replies: 7
- Views: 3951
- Wed Dec 27, 2006 3:04 am
- Forum: Fans and Control
- Topic: blowers vs fans
- Replies: 7
- Views: 3951
Hi, Yes... I too am unclear about this distinction between a blower and a fan. However, the CPU fan is being used to push air through the CPU heatsink, which is in fact a pretty substantial obstacle to airflow. The actual airflow is way down on the free flow CFM the maufacturere would quote; and the...
- Wed Dec 27, 2006 3:00 am
- Forum: Fans and Control
- Topic: Do you really need an exhaust fan
- Replies: 7
- Views: 2978
Hi, As Bluefront suggests, it all depends on the case layout and airflow design. The important thing is that hot air is coming off the CPU cooler; and you have to have some means to make sure that a good proportion of that hot air goes out of the case. Otherwise the inside of the case wil just get h...
- Wed Dec 27, 2006 1:58 am
- Forum: Fans and Control
- Topic: Restriction?
- Replies: 20
- Views: 7924
Hi, Could we possibly extend this to measuring the resistance or actual airflow through a CPU heatsink. I'm not certain that I beleive the manufacturers quoted figures fro CFM: but even if I did they are CFM in free air; and the Heatsink represents a massive resistance to airflow. The actual aiflow ...
- Tue Dec 26, 2006 11:55 am
- Forum: Fans and Control
- Topic: Are 2 fans noisier than 1 blowing the same CFM?
- Replies: 64
- Views: 230355
- Tue Dec 26, 2006 4:22 am
- Forum: Fans and Control
- Topic: Are 2 fans noisier than 1 blowing the same CFM?
- Replies: 64
- Views: 230355
Hi, I think you need to know the total noise output of the fans to be certain. You will certainly end up with more CFM using 2 @ 5V rather than 1 @7V: just over 40% more in fact. In dBA terms you have both a reduction and an increase, so the net effect is hard to calculate. Each fan at 5V will produ...
- Tue Dec 26, 2006 3:09 am
- Forum: Fans and Control
- Topic: 140mm fan experience and where to buy?
- Replies: 18
- Views: 12183
Hi, I'm also using the AeroCool Sreamliner, but my experience is different. It moves slightly less air than many 120mm fans - true: but it runs at 1000 rpm max, and produces much less niose. Mine start at below 4V and will run smoothly down to about 470 rpm. I get the impression that they are less s...
- Tue Aug 01, 2006 12:11 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi Isaac, Have you tried running the machine cooled by the Zalman VGA cooler at 100% CPU for a few days. Nope. I'm never going to run it at 100% CPU for any significant length of time. If I want computing power, I'm not going to use a mere 564mhz Pentium III when I've got a 2.4Ghz Pentium IV around....
- Mon Jul 31, 2006 1:10 pm
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi Isaac, Yes just one minimum speed 80mm fan. But none of my systems are anywhere near as powerful as yours! I only do shoestring budget computers. I recently got my hands on some cheap Sempron 3100 combos--those were massive upgrades for me. I just had a look at the stuff you posted in the general...
- Mon Jul 31, 2006 11:12 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi Isacc, Yes... that limit was implicit im my argument. It remains true that if anybody made larger fans that would start up at all under suitable voltages you wouold still get less noise from the bigger/slower route. There is probably some other limit here as well.... I'm surprised/impressed at wh...
- Mon Jul 31, 2006 9:54 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi, Surely the reason for isolating the components is that they all have different cooling requirements that vary independently of one another. For example, a hard disk must be kept at a much lower temperature than for example a CPU, but conversely needs much less airflow to keep it at that temperat...
- Mon Jul 31, 2006 9:40 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi Bluefront, "Typically this will reduce noise levels by 10 times"........just where do you get that figure? But you miss the point......with proper design/airflow, you can get the same cooling, at the same noise level, with fewer fans, the minimum being one. dB is roughly proportional to CFM for a...
- Mon Jul 31, 2006 3:48 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi, matter of opinion....more fans equal more cost, more trouble to mount, more chances for bearing noise, more difficulty to filter, more chances for failure, and so on. We have yet to see the perfect airflow in a case which results in the quietest/coolest computer. But IMHO, that perfect airflow w...
- Sun Jul 30, 2006 3:09 am
- Forum: The Silent Front
- Topic: Isolating hot components from each other - is there a point?
- Replies: 28
- Views: 15652
Hi, This question has no answer. There is no single right way. Seriouly.... because the devil is in the detail. The best arrangement depends entirely on exactly how much haet each component happens to create, and how hot it can run. Just consider the following simple question. If you have a separate...
- Thu Jul 27, 2006 8:01 am
- Forum: The Silent Front
- Topic: Less airflow equals cooler temps.....
- Replies: 21
- Views: 11404
But I think that you're right that the BTX design exauasts the hot air from the output side of the CPU cooler straight out of the case. It's pretty obvious that you don't want to allow the hottest air to re-circualte... That's pretty obvious to everybody except the people making 120W CPUs. BTX feed...
- Thu Jul 27, 2006 5:04 am
- Forum: The Silent Front
- Topic: Less airflow equals cooler temps.....
- Replies: 21
- Views: 11404
Hi, The case is 7" by 18" by 22". That's about as small as I can make it and still get the three internal 120mm case fans in. We've worked on the mufflers since those details were posted. The best I've had has been an X2 4800 plus 2 300GB HD and a fanless nVidia7300 running flat out (2 copies of Pri...