 | ||
|
||
|
|||||||
| General Liquid/Water Cooling Discussion For discussion about Full Cooling System kits, or general cooling topics. Keep specific cooling items like pumps, radiators, etc... in their specific forums. |
 |
| Thread Tools |
07-14-2003, 09:13 PM
|
#1 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
Taming my Comair Rotron
I don’t know if this info has been posted before, but here goes.
Several months ago I purchased a Comair Rotron Major 12VDC axial fan, model number JQ12ROX, 235cfm, 171.5mm x 150.4mm x 50.8mm. The cost was right, 14.95USD, so I bought 2 of them from MPJA. Well I finally decided to see how to use all of its features. This is a discontinued model (mfg OCT 2000 I think). Comair does not have info on their web site for this model. It has 4 leads coming out to a nice 5 pin socket:: 1 red lead wire (obviously the +12vdc) 2 blank socket pin 3 yellow lead wire (?) 4 blue/white striped lead wire (?) 5 black lead wore (obviously the – return) My electronics knowledge is very limited. But I do not shy away from the simple things (soldering, measuring resistance, etc). At the Comair site I found some info in their engineering notes: Their fans have built in electronics for extra functions, but different models have different ways of implementing this. Speed control: http://www.comairrotron.com/Engineer...olFanSpeed.htm The yellow wire is for speed control I decided to see if the simple implementation was used. I shorted out the yellow lead to the black lead and sure enough the fan speed dropped significantly (low speed). This is great so I found a 10K pot in my collection and placed it between the yellow lead and the black lead. This allowed me to continuously vary the speed from full to half speed. I noticed that the sound no longer changed about half way in the rotation of the pot wiper. So I left it there and measured the resistance at that point. It was close to 5K. No 5K pots in my collection. So I’m off to the local Radio Shack. Where I purchased a 5K ohm 0.5watt linear pot (part number 271-1714). With this between the yellow and black leads I had full speed control over the full range of the pot. None of the fan controllers, that we see advertised everywhere, can be used even if they could handle the 2.26 amps (27watts) that this fan needs. Changing the voltage on the +12 volt lead (red wire) only gives you 2 speeds (internal electronics on the fan does this). From ~ +6 to +12 gives you the high speed. Below ` +6 volts gives you the low speed. But this cheap little pot on the speed control lead (yellow wire) does the trick. Performance monitoring. http://www.comairrotron.com/Engineer...torFanPerf.htm The blue/white wire is for fan performance monitoring (RPM) Now to see if the performance lead (blue/white) is the simple 2 pulse per revolution output used by some fans in our computers. I placed one end of a micro clip on the pulse sensor lead on one of the fan sockets of my DigitalDoc 5. The other end of the micro clip was placed on the blue/white lead from the fan. It worked. The DigiDoc showed 3520 RPM at full speed and 1344 RPM at low speed. Now all I need is a plug for the blue/white lead. That’s how I tamed my Comair Rotron. If yours has a different model number it may require other solutions. Next on my list, building a radiator shroud for this fan. At the rate I’m going it may be quite a while. I have made 2 that were complete disasters. Oh well live and learn.
__________________
Have fun, FuzzyFace |
|
|
|
07-14-2003, 09:55 PM
|
#2 |
|
Responsible for 2%
of all the posts here. 
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Excellent work.
|
|
|
|
|
07-14-2003, 10:02 PM
|
#3 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
Thanks BB2k.
A few people have talked about using these big Comair Rotrons but I dont remember anyone saying how to use them.
__________________
Have fun, FuzzyFace |
|
|
|
|
07-16-2003, 02:35 PM
|
#4 |
|
Cooling Neophyte
Join Date: Jul 2003
Location: nyc
Posts: 1
|
I have these fans and they work great on this fanbus that I found on SVC. it was also cheap. Each channel can handle 23 watts or so so its great. Fans are damn hazardous though.
|
|
|
|
|
07-16-2003, 03:18 PM
|
#5 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
I've got a related Q:
I've been looking for another blower, because the one I picked up was too large, with a motor protruding quite extensively. So I recently came across this: http://www.allelectronics.com/cgi-bi...171&type=store It's a Comair Rotron, with the same leads, but no stats. From the power draw, I can only assume that it's not rated as high as I want it. Also, it doesn't match any other blower, from the Comair Rotron website, except in dimensions: http://www.comairrotron.com/pdfs/DD4021Series.PDF (PDF 2 pages). I'm a little puzzled. 4" would be perfect, but if that blower draws .25 amps, then it's only 3 Watts. If it's a typo, then it would be 1.25 amps, which would make a lot more sense, and match almost perfectly the stats for the first blower on that spec sheet. Also, the pressure measurement is in "Ps", which I can't reconcile: is it Pascal, or psi, or something else? If it's a Pascal, then it's equivalent in centimeters of water, is 0.01, which is awfully low. If it's psi, then it's equivalent in centimeters of water, is 77, which is awfully high. :shrug: |
|
|
|
|
07-16-2003, 05:35 PM
|
#6 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
bigben2k:
I think the words motorized impeller are important here. Doesn’t that mean there is no cage around it to direct the input and output of air. I do not know if these motorized impellers are supposed suck air in the center hole or blow it out the center hole. Also the picture in the AllElectronics url only shows 4 leads. Red and black for the 12vdc. The other 2 are solid white and solid blue, which I could not find any reference to in the Comair engineering notes. The PQX in the model number leads me to believe that it is in the era of model numers as my ROX. It’s almost impossible to get info on old Comair Rotrons from searching on the net. I would venture a guess, just a wild guess, that the de18 means 18cfm (sort of fits in the rest of the data). So i would assume that it does not have the power you need.
__________________
Have fun, FuzzyFace |
|
|
|
|
07-16-2003, 06:07 PM
|
#7 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
The DD4021 series comes standard with tach output, so I have to assume that that's what they are. I'll have to see how it would run at different voltages. The "yellow" cable, which would normally control the fan, is not an option, but there's a reference to an optional "thermal speed control" and "programmable speed control".
These "motorized impellers" suck air from the center: the rotation throws the air around, by centripedal force. Typically, the blades are straight, but the more advanced designs have "backward" blades, like this one, which I believe provides even more pressure, at the cost of a bit of flow. I'll have to confirm the typo. I can't believe that the same size wheel would only draw ".25 amps". The RPM would have to be substantially lower, possibly under 500 rpm, and I just can't imagine that as being realistic. So if it's good, I could pick up two of these, since they're only 4" in diameter, and ~2" thick. The trick would be to duct an air inlet to both... More thought required... Any idea about the unit used in the pressure chart?  I really need to figure that one out!
|
|
|
|
|
07-16-2003, 06:36 PM
|
#8 |
|
Cooling Savant
Join Date: Sep 2002
Location: Omaha, NE USA
Posts: 216
|
After looking at a couple of other motorized impellers from other manuf's, what you are looking at is inches of water. The Ps that is on their PDF is for 'pressure static'.
You need to clear up the .25A current draw. If it was a custom fan for someone it might be a slow, quiet blower. Taking the specs for their current 4021 and lowering the curve for only .25A would give you a fan that gives about 25 cfm @ .3 inches of water. Not exactly what I think you were looking for. Hope this helps. |
|
|
|
|
07-16-2003, 06:44 PM
|
#9 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Thanks Murray13, somehow, I knew you'd chime in here!
I e-mailed AllElectronics. I guess it'll have to wait until tmo at least, for an answer. I just hope that they don't bump up the price, when they find out the real specs. That makes sense about the inch: the axial fans are all rated that way. If the amp draw is 1.25, then it's the right unit for my project. Now to draw up the duct... 
|
|
|
|
|
07-16-2003, 07:04 PM
|
#10 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
Bigben2k:
All I had was the engineering notes for their current fans. My guess’ on the function of the leads worked out great. It turns out that not all the info there is valid for my fan as wizard115 pointed out. He found that a reho bus would continuously vary the speed by varying the voltage from 7 to 12 on my old model number fan. But the engineering notes say it does not work way. What does that mean? You just have to experiment around to find out what works. I do not have a reho bus that will handle that many watts. But my 2$US pot on the controller lead sure beat the price of a reho bus. The only way to find out is to buy one. cost for your blower is only 6$US plus shipping, not bad at all. Using the tach output may give the info you need (lower amps, lower rpm = lower cfm?). Have fun experimenting with it. Ops I see murray13 came in with some better info. Good luck
__________________
Have fun, FuzzyFace |
|
|
|
|
07-16-2003, 07:16 PM
|
#11 | |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Got a reply!
Quote:
 Let's see if a second round will help... |
|
|
|
|
|
07-16-2003, 08:41 PM
|
#12 | |
|
Cooling Savant
Join Date: May 2002
Location: Ohio-State! <--Money Hussle! SUCKS
Posts: 292
|
Quote:
__________________
XP 1600+ AGOIA-Y (GreenLabel, UNLOCKED!@/ NF7-S 2.0/ PC 2700 DDR 10.5*172FSB(1806/ 1991 high), Vcore 1.792...@84.95Watts --86' Chevette Heater Core --1/2" Vinyl tubes --Via1300-Stealth Mod(QUIET!)  ---Home made copper-tube block ---PVC small internal res |
|
|
|
|
|
07-16-2003, 09:50 PM
|
#13 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
V12|V12:
The speed controller lead is yellow. I placed a pot between it and the ground lead (black lead). It does not need to be large watt unit. My electronics knowledge is very limited but let me explain in the terms of one who knows not. The Comair fan has a lot of electronics inside the fan that we can’t see. This electronics performs all of the extra functions for the fan. The fan speed controller circuitry (like a reho bus) for the most part is low power. Look at the resistors in a reho bus they are low watt, ¼ or ½ watt units, the same goes for the pot that we rotate to select the speed we want. Now these low power parts do their thing and talk to the high power voltage regulator that is connected to it and tell it to change its output voltage to what we wanted. So, the pot on the speed controller lead can be a low watt value, and that’s why I selected a 5K ohm ½ watt unit. If you placed a pot on the 12VDC lead I think it would have to be a high watt unit like the one you were talking to the RS guy about. Now an electronics expert may come along and punch all kinds of holes in my explanation, and give a better description.
__________________
Have fun, FuzzyFace |
|
|
|
|
07-17-2003, 09:54 AM
|
#14 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
I e-mailed comair-Rotron in Europe (only available e-mail addy), to see if they could spec out the fan.
No reply from AllElectronics. |
|
|
|
|
07-17-2003, 12:30 PM
|
#15 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Hum... I came across this article about blowers (sorry for the hijack), from one of our favorite websites:
http://www.electronics-cooling.com/R...6/may96_01.htm So I e-mailed the guy, to see if he's got specs (He's in the California office). |
|
|
|
|
07-17-2003, 03:39 PM
|
#16 | |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Round 2 results:
Quote:
I e-mailed Comair-Rotron's sales dept. Maybe they can dig up the specs.:shrug: |
|
|
|
|
|
07-17-2003, 07:59 PM
|
#17 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Woohoo!
I got a reply from Comair. Mr Nilo, the application engineer is going to let me know tomorrow, what the specs are! |
|
|
|
|
07-17-2003, 08:47 PM
|
#18 | |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
Quote:
__________________
Have fun, FuzzyFace |
|
|
|
|
|
07-18-2003, 12:53 PM
|
#19 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Still no answer, so I'm taking a peak at alternatives:
http://www.allelectronics.com/cgi-bi...149&type=store Pulling the specs for a similar unit, from the Delta website: max flow: 32.49 cfm max pressure: 1.06" H2O http://www.delta.com.tw/products/dcf...FB12012032.pdf (PDF, 1 page) Maybe by "stacking" a few of these, it would work. I could probably fit 4 of them, while allowing for an intake. What I'm really after, is that 0.25" H2O, like Bill tested. |
|
|
|
|
07-18-2003, 03:59 PM
|
#20 | |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
 Quote:
So I sent a reply, asking if I could have at least a comparable RPM range, to the curent DD4021 series, and pointing them with the link to the unit, now publicly sold. On to round 3...
|
|
|
|
|
|
07-18-2003, 04:23 PM
|
#21 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Round 3.5
Here's the motorized impeller unit, from APW: http://www.apw.com/productsServices/.../raptor567.jsp So I e-mailed their sales dept, and CC'd the Comair rep. Realistically though, from the specs and model numbers listed, I'm looking at a 23 CFM unit
|
|
|
|
|
07-18-2003, 05:33 PM
|
#22 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
An alternative, but this one is AC
http://www.ctrsurplusonline.com/prod...235&1=236&3=72 Another alternative, DC, but low powered: http://www.surpluscenter.com/item.as...tname=electric Last edited by bigben2k; 07-18-2003 at 05:50 PM. |
|
|
|
|
07-18-2003, 07:26 PM
|
#23 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
bigben2k:
I have no problems using 120vac fans in my case. At one time I had 3 ac fans in my case all on fan controllers that I purchased from Edmund Scientifics. Those little (on a 1 ½” x 1 7/16” pcb) controllers worked great. http://www.scientificsonline.com/ec/...egoryID=323774 They did not include any literature with the controllers. So I don’t know what the wattage limit is. For several months now I have not been using a case (it is easier to change things around when everything is out on the desk). So my case fans are not needed. By now you will have guessed that I like to control the speed (sound) of my fans.
__________________
Have fun, FuzzyFace |
|
|
|
|
07-18-2003, 07:36 PM
|
#24 |
|
Responsible for 2%
of all the posts here.
Join Date: May 2002
Location: Texas, U.S.A.
Posts: 8,302
|
Not bad!
The AC blower linked above is 94 Watts, which would be less than 1 amp. Do you have any numbers about the fans that you controlled? |
|
|
|
|
07-18-2003, 07:51 PM
|
#25 |
|
Cooling Neophyte
Join Date: Dec 2001
Location: California high desert
Posts: 52
|
Bigben2K:
I will see if I can find those fans. Then do a little experiment with all three hooked up to one controller. It will take a little while to find the fans. I am notorious for losing things in the computer room here in my apartment.
__________________
Have fun, FuzzyFace |
|
|
|
|
«
Previous Thread
|
Next Thread
»
| Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|
All times are GMT -5. The time now is 04:01 AM.