I have a asrock x670e pro rs motherboard and was wondering if i could separate the fans and use one for the cpu and one as an exhaust fan for my case, controlled via pwm on the motherboard and wiring the power via molex so it can all be controlled via BIOS software and kept under say 5000rpm??
They are counter-rotating. All axial fans twist the air, which is wasted energy when linear flow is desired, and also increases the resistance when flowing through a radiator. Some fans use static vanes (stator vanes) to straighten the airflow a bit more gradually so that there is less energy loss (like having a curved corner in a duct vs a sharp corner). But some other fans straighten the airflow with a counter-rotating rotor, especially when the application demands high performance. It also has advantages with reliability, because there is redundancy. If one fan fails, the other one can continue working until the unit can be replaced.
I have a kinda improvised solution for this. I basically split an extension cable so that it can be connected directly to the PSU for power (via Molex connector), but the PWM and Tach leads still go to a controller (NA-FC1 in my case). This is also useful for controlling the speed of 3-pin fans. Instead of connecting to the PSU, I just connect that to some DC fan speed controller I bought off Aliexpress, while the Tach still goes through the NA-FC1 and back into my motherboard. I wish there was a more off-the-shelf solution for this, but it works for me.
@@ydihtty damn, a bit too difficult for me i think. I dont know how i would go about doing this. Yeah ive seen that noctua controller. Webshop claims it can do max 3 amps. Is that true?
@@branchprediction9923 That is true, it seems to have a current limiter too, I've noticed some more powerful fans will have a lower max speed and gentler startup. But there are plenty powerful fans below 3 amps.
@@ydihtty my friend, i have a question. If i connect a 3 pin dc fan to that nactua fan controller (which is a 4 pin) will the fan run at max rpm regardless of the knob/speed?
@@branchprediction9923 If it pulls 3A or below, and the controller is powered via SATA, it will run at max speed, regardless of the knob. I think you can power the controller via the motherboard, and if you reduce the voltage from the motherboard, that will reduce the fan speed. I haven't tried this though.
It significantly increases static pressure, and creates a very focused airflow. With a single rotor, the air is pushed axially, but also twisted, so there is wasted energy, and there is more resistance when trying to push air through a heatsink. Stator vanes help straighten the airflow, but they cause some loss. A counter-rotating fan basically "un-twists" the airflow, converting all the wasted twisting motion into straight airflow. This video illustrates it pretty well: th-cam.com/video/fsHXWFrJfD4/w-d-xo.html
@@ydihtty This is really interesting, thanks! But now another question arises for as to why they are designed to rotate at different RPM over at same RPM. I suppose it's due inefficiencies or diminishing returns?
I'm not exactly sure, but I think the inlet creates all of the airflow, and the outlet fan is only responsible for un-twisting the air. So the speeds are probably tuned (I'm guessing) such that the outlet un-twists the airflow enough, but not too much, otherwise it would start twisting the airflow in the opposite direction.
Frekking hell, sure sounded like it was going to blow in the end!
Thanks for the video
Yeah I'm not sure if I got it up to full speed, I was getting scared too tbh lol. I should get some protective goggles
sounded like regular car engine running past 8000 rpm when 7000rpm is start of redline
Crazy fan speed haha
Ultraflow fans are usually quite good as far as noise level. I wonder why this one is so loud.
12980 RPM
I have a asrock x670e pro rs motherboard and was wondering if i could separate the fans and use one for the cpu and one as an exhaust fan for my case, controlled via pwm on the motherboard and wiring the power via molex so it can all be controlled via BIOS software and kept under say 5000rpm??
At 6,500 RPM, it sounded like a aca allertor.
is there a way to make it silent with that speed? i mean the voice come from friction
What would be the purpose of putting 2 fans one behind the other like this with nothing in between, doesnt seem to make a lot of sense
They are counter-rotating. All axial fans twist the air, which is wasted energy when linear flow is desired, and also increases the resistance when flowing through a radiator. Some fans use static vanes (stator vanes) to straighten the airflow a bit more gradually so that there is less energy loss (like having a curved corner in a duct vs a sharp corner). But some other fans straighten the airflow with a counter-rotating rotor, especially when the application demands high performance.
It also has advantages with reliability, because there is redundancy. If one fan fails, the other one can continue working until the unit can be replaced.
@@ydihtty Very interesting indeed.
crazy...
how do you power that thing? id love to buy a fan controller or something to power such a beast.
I have a kinda improvised solution for this.
I basically split an extension cable so that it can be connected directly to the PSU for power (via Molex connector), but the PWM and Tach leads still go to a controller (NA-FC1 in my case).
This is also useful for controlling the speed of 3-pin fans. Instead of connecting to the PSU, I just connect that to some DC fan speed controller I bought off Aliexpress, while the Tach still goes through the NA-FC1 and back into my motherboard.
I wish there was a more off-the-shelf solution for this, but it works for me.
@@ydihtty damn, a bit too difficult for me i think. I dont know how i would go about doing this.
Yeah ive seen that noctua controller. Webshop claims it can do max 3 amps. Is that true?
@@branchprediction9923 That is true, it seems to have a current limiter too, I've noticed some more powerful fans will have a lower max speed and gentler startup. But there are plenty powerful fans below 3 amps.
@@ydihtty my friend, i have a question. If i connect a 3 pin dc fan to that nactua fan controller (which is a 4 pin) will the fan run at max rpm regardless of the knob/speed?
@@branchprediction9923 If it pulls 3A or below, and the controller is powered via SATA, it will run at max speed, regardless of the knob.
I think you can power the controller via the motherboard, and if you reduce the voltage from the motherboard, that will reduce the fan speed. I haven't tried this though.
What's the use of such inlet and outlet stuck together design?
It significantly increases static pressure, and creates a very focused airflow. With a single rotor, the air is pushed axially, but also twisted, so there is wasted energy, and there is more resistance when trying to push air through a heatsink. Stator vanes help straighten the airflow, but they cause some loss. A counter-rotating fan basically "un-twists" the airflow, converting all the wasted twisting motion into straight airflow. This video illustrates it pretty well: th-cam.com/video/fsHXWFrJfD4/w-d-xo.html
@@ydihtty
This is really interesting, thanks!
But now another question arises for as to why they are designed to rotate at different RPM over at same RPM.
I suppose it's due inefficiencies or diminishing returns?
I'm not exactly sure, but I think the inlet creates all of the airflow, and the outlet fan is only responsible for un-twisting the air. So the speeds are probably tuned (I'm guessing) such that the outlet un-twists the airflow enough, but not too much, otherwise it would start twisting the airflow in the opposite direction.
It is used to cool the sun
We finally know what fans do Sony use in ps4
Im scared..
So was I lol
Now , install on cpu
sounds like a 2.4 v8