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Control powerfull pwm fans with Pi

Posted: Sat Mar 16, 2019 7:33 pm
by lexkiev
Hello guys, I'm pretty new to Pi so i need you help to build small project.
I need to use my Pi as fans controller. I got 4 powerfull 12v 2.7A 4pin PWM fans and need to control it from Pi.
I want to use external power supply to give them propper power and pi as a rpm monitor/controller.

Anyone can give me instruction how to wire this up and connect everything together?

Thanks in advance!

P.S. Software is not a problem, need help only with hardware connection.

Re: Control powerfull pwm fans with Pi

Posted: Sun Mar 17, 2019 2:36 pm
by pcmanbob
If you want help you need to provide detailed information about the fans you wish to connect, It would help help if you post a link to the fans in question or a data sheet giving connection / rating / control information.

Re: Control powerfull pwm fans with Pi

Posted: Sun Mar 17, 2019 10:39 pm
by lexkiev
pcmanbob wrote:
Sun Mar 17, 2019 2:36 pm
If you want help you need to provide detailed information about the fans you wish to connect, It would help help if you post a link to the fans in question or a data sheet giving connection / rating / control information.
need to connect and controll 4 of this fans
https://ru.aliexpress.com/item/Emacro-S ... 51385.html

Model Number: SG121238BS

Voltage : DC 12V

Current : 2.7A

Speed: 6000RPM


Power range: plus or minus 15% of rated power
Withstand voltage: sink current 0.5mA 500V / 1 minute

Re: Control powerfull pwm fans with Pi

Posted: Mon Mar 18, 2019 8:17 am
by pcmanbob
I don't have a spare 4 wire fan to test this so its based on reading the data sheet for a typical 4 wire fan.

https://www.glkinst.com/cables/cable_pi ... M_Spec.pdf

Image

I suggest you read the linked data sheet for yourself.

Re: Control powerfull pwm fans with Pi

Posted: Wed Apr 17, 2019 5:59 pm
by JonnyQuest
I am interested in the same topic. Since my background is not in electrical engineering, I need a little more explanation than a diagram. In my instance, I want to control 2 fans synchronously (http://www.delta-fan.com/Download/Spec/ ... DE-F00.pdf). These are 4pin PWM fans from a server. For testing, I am using a Pi3B+ attached to a breadboard with an external power source (PC power supply) for the fans. In the final configuration, I will be using a PiZeroW for a controller and the same external power supply. It would be nice to power the Pi from the external source as well since there is a 3.3v rail but that is a different topic.

Re: Control powerfull pwm fans with Pi

Posted: Wed Apr 17, 2019 10:13 pm
by mikronauts
Use a cheap L298 driver module, using a 12V power adapter for the fan (one module could handle two independent fans)

If you google Raspberry Pi L298 you will find plenty of articles on driving motors like this.
JonnyQuest wrote:
Wed Apr 17, 2019 5:59 pm
I am interested in the same topic. Since my background is not in electrical engineering, I need a little more explanation than a diagram. In my instance, I want to control 2 fans synchronously (http://www.delta-fan.com/Download/Spec/ ... DE-F00.pdf). These are 4pin PWM fans from a server. For testing, I am using a Pi3B+ attached to a breadboard with an external power source (PC power supply) for the fans. In the final configuration, I will be using a PiZeroW for a controller and the same external power supply. It would be nice to power the Pi from the external source as well since there is a 3.3v rail but that is a different topic.

Re: Control powerfull pwm fans with Pi

Posted: Thu Apr 18, 2019 7:00 am
by Brandon92
mikronauts wrote:
Wed Apr 17, 2019 10:13 pm
Use a cheap L298 driver module, using a 12V power adapter for the fan (one module could handle two independent fans)

If you google Raspberry Pi L298 you will find plenty of articles on driving motors like this.
That will not work in this case. The fan is more than 40W and that is to much for that driver. He need to use the previous schematic that is also showed in the fan datasheet.

Re: Control powerfull pwm fans with Pi

Posted: Thu Apr 18, 2019 10:15 am
by joan
Don't the fans require a rather odd PWM sequence to start up? I have a memory of proper 4-pin fans not being easily controllable from the Pi.

Re: Control powerfull pwm fans with Pi

Posted: Thu Apr 18, 2019 9:39 pm
by mikronauts
Good point, max current is only 2A on the L298.
Brandon92 wrote:
Thu Apr 18, 2019 7:00 am
mikronauts wrote:
Wed Apr 17, 2019 10:13 pm
Use a cheap L298 driver module, using a 12V power adapter for the fan (one module could handle two independent fans)

If you google Raspberry Pi L298 you will find plenty of articles on driving motors like this.
That will not work in this case. The fan is more than 40W and that is to much for that driver. He need to use the previous schematic that is also showed in the fan datasheet.

Re: Control powerfull pwm fans with Pi

Posted: Thu Apr 18, 2019 9:51 pm
by mikronauts
No idea, but as this is interesting, I googled a bit:

https://www.ekwb.com/blog/what-is-pwm-a ... s-it-work/

Shows a four pin pwm fan with the following signals

GND, 12v, Tach, PWM

Apparently ome fans have a controller that shape the PWM with ramping rising/falling edges.

http://forum.arduino.cc/index.php?topic=18742.0

Suggests fans need a 25khz PWM signal.
joan wrote:
Thu Apr 18, 2019 10:15 am
Don't the fans require a rather odd PWM sequence to start up? I have a memory of proper 4-pin fans not being easily controllable from the Pi.

Re: Control powerfull pwm fans with Pi

Posted: Thu Apr 18, 2019 10:25 pm
by Imperf3kt
mikronauts wrote:
Thu Apr 18, 2019 9:39 pm
Good point, max current is only 2A on the L298.
Well, you can parallel up the inputs and outputs on this chip to make a 4A continuous drive bridge but that's still far short of 40W

Re: Control powerfull pwm fans with Pi

Posted: Fri Apr 19, 2019 2:07 am
by mikronauts
Actually that would be enough as 12v * 2a * 2 is 48W
Imperf3kt wrote:
Thu Apr 18, 2019 10:25 pm
mikronauts wrote:
Thu Apr 18, 2019 9:39 pm
Good point, max current is only 2A on the L298.
Well, you can parallel up the inputs and outputs on this chip to make a 4A continuous drive bridge but that's still far short of 40W