Is DC current fan better than AC current fan (for odor control)?

lazaah said:

Infinity are EC fans that use a DC motor and use a PWM signal to speed control (like controlling a servo with arduino)

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Hi Lazaah, based on the comment by Jesusgrowsmygrass it uses "PWM from 0-10V", I think that means it's not a PWM signal you put into it but rather it generates it's own PWM signal based on your input of a voltage between 0 and 10 volts, in which case maybe it's continuous speed change proportional to your voltage input. So if I understand correctly they don't let you put your own PWM signal straight in like you would with a servo. Correct?

raggyb said:

Hi Lazaah, based on the comment by Jesusgrowsmygrass it uses "PWM from 0-10V", I think that means it's not a PWM signal you put into it but rather it generates it's own PWM signal based on your input of a voltage between 0 and 10 volts, in which case maybe it's continuous speed change proportional to your voltage input. So if I understand correctly they don't let you put your own PWM signal straight in like you would with a servo. Correct?

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You are correct that you don't put in your own PWM signal straight into the fan, but modify the fans own pwm signal. How that is done is dependent it is dependent on the fan manufacturer. My oversimplified point was that, in speed controlling EC fans, we're indirectly modifying the DC voltage of the DC fan motor itself rather than the input ac voltage or voltage across an AC motor (as you would using a variac).

We've had a couple relevant threads going here:

lazaah said:

You are correct that you don't put in your own PWM signal straight into the fan, but modify the fans own pwm signal. How that is done is dependent it is dependent on the fan manufacturer. My oversimplified point was that, in speed controlling EC fans, we're indirectly modifying the DC voltage of the DC fan motor itself rather than the input ac voltage or voltage across an AC motor (as you would using a variac).

We've had a couple relevant threads going here:

DIY EC Fan controller?

Can anyone confirm whether 0-10v pwm is the standard for EC fan speed control? I'm in the market for an EC fan. Probably go with a Mountain Air 8in, as that's what's best available locally. It comes with a basic speed controller, but I'd like to craft up something with more flexibility. I...

www.rollitup.org

Dimmable HLG driver Optocoupler or Transistor, does it matter? (and other questions)

Oops, wrong thread. That's ok, both threads really deal with the same principle. The AC infinity seems to be the same as the meanwell except that I do not have a ground to connect to HVG on the meanwell. With the info you provided I think I should be able to get this going without frying...

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thanks for pointing these threads out. I was reading the second one already but was not understanding though maybe i was too high at the time.

Yes you use the devices own electricity for the PWM signal, for example with the ACInfinity fan, turn up the controller to the highest setting and "intercept" the full power signal then ontrol it with a transistor and the output of the Raspberry Pi/arduino to control to your desired pulse width. Yes it is a bit complex but if you can dim an LED with the Raspberry Pi or Arduino you can do PWM. This will also control Meanwell type B drivers. I got the idea from LEDGardener on the tube of you @@@@5:04 in to the video.

Jesusgrowsmygrass said:

Yes you use the devices own electricity for the PWM signal, for example with the ACInfinity fan, turn up the controller to the highest setting and "intercept" the full power signal then ontrol it with a transistor and the output of the Raspberry Pi/arduino to control to your desired pulse width. Yes it is a bit complex but if you can dim an LED with the Raspberry Pi or Arduino you can do PWM. This will also control Meanwell type B drivers. I got the idea from LEDGardener on the tube of you

@@@@5:04 in to the video.

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thanks JesusGrowsmygrass. nice vid. He grows peppers, lol.
I got the PWM signal making down so I'm ok there. I see he has the temp/h controller version of the cloudline, not the knob controller. That version might make a difference. The temp/h controller is where he says he intercepts the pwm signal, so i think at least that version fan must take a pwm signal from that control into the fan somewhere but I guess it's not the so called 'PWM interface' which in truth sounds like it is simple 0-10v in and not PWM in. Furthermore I'm not sure if that infinity controller uses wifi to the fan or a wire connection. So I still wonder do all the cloudlines have a connection wire you could use for true PWM in? Maybe you have to open the fan and cut a wire to get at the pwm signal? If my guess is right then the cut in point would be after the 0-10v interface and after some PWM generator that connects to. Do you know offhand? And maybe you still need to add 10V to amp the PWM's amplitude to 10V. Apologies ahead of time for all the questions.

raggyb said:

thanks JesusGrowsmygrass. nice vid. He grows peppers, lol.
I got the PWM signal making down so I'm ok there. I see he has the temp/h controller version of the cloudline, not the knob controller. That version might make a difference. The temp/h controller is where he says he intercepts the pwm signal, so i think at least that version fan must take a pwm signal from that control into the fan somewhere but I guess it's not the so called 'PWM interface' which in truth sounds like it is simple 0-10v in and not PWM in. Furthermore I'm not sure if that infinity controller uses wifi to the fan or a wire connection. So I still wonder do all the cloudlines have a connection wire you could use for true PWM in? Maybe you have to open the fan and cut a wire to get at the pwm signal? If my guess is right then the cut in point would be after the 0-10v interface and after some PWM generator that connects to. Do you know offhand? And maybe you still need to add 10V to amp the PWM's amplitude to 10V. Apologies ahead of time for all the questions.

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Could you email infinity and ask? While mentioning you know it will void your warranty

The ACInfinity uses a standard computer 4 prong molex connector. If you buy something like this, https://www.amazon.com/Coolerguys-4-Pin-Molex-Sleeved-Extension/dp/B005CM8AHQ?th=1 and intercept the pwm wire you can hook up the fan properly without any permanent evidence it was done.

I take your word for it that it's PWM out of the remote control. I might like to put a scope on to measure the duty cycle but I don't want to buy one. Maybe it's the transistor you're doing something with I dont get. Full power PWM -> Transistor -> Arduino PWM => modified PWM signal??? That's foreign to me. What's the transistor's function here?

Jesusgrowsmygrass said:

turn up the controller to the highest setting and "intercept" the full power signal then ontrol it with a transistor and the output of the Raspberry Pi/arduino to control to your desired pulse width.

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Hi guys, I've been searching for how to do this as I'm considering buying both a S4 and a S6 and want to fully control them. Looking at the specs on Amazon the fan has a standard molex connector. I'm a programmer by trade and have a Raspberry Pi, Relays and some fun LED stuff on order. Tutorials look pretty easy.

I like the idea of being able to make a connector and not modify any of the internals of the fan as Jesusgrowsmygrass wrote. https://www.amazon.com/Coolerguys-4-Pin-Molex-Sleeved-Extension/dp/B005CM8AHQ?th=1

Has anybody actually done this? Anyone have a parts list of stuff needed etc? Reason I have chosen AC Infinity is because they have a good reputation and also run on 220V (as well as 110V). I have to import all from USA. I see many fans specced for 110V only, which are not suitable.

The S4/6 fans make 10V that you can turn into a pwm signal to control the fan.
See here

shimbob said:

The S4/6 fans make 10V that you can turn into a pwm signal to control the fan.
See here

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Thanks Shimbob, yeah I gathered that my 10V would come from the Cloudline thanks to your earlier excellent work. Looking at the photos in your thread I see 2 optoisolators which I presume are for safety and not absolutely necessary. What is the actual device that drives the PWM on the Cloudline, using the 10V ?

I would write some sort of psuedo-code like this on the Pi. Other than a Pi and perhaps a pair of optoisolators for circuit safety, a molex connector to wire up (keep connector that comes with Cloudline intact) I am not sure what else I need.

1) Wait for certain event
2) Turn on relay (220V AC) to Cloudline.
3) Send PWM signal for n% of power.
4) Wait for certain event
5) Turn off relay (AC) to Cloudline.
6) Goto 1

I have already ordered a computer PSU breakout box to get a nice DC supply for some other stuff in the tents, some relays to power lights etc... but am not sure what specific things I need to get this Cloudline PWM working fine. Also my LEDs have dimmers (which means more cool PWM ideas), but that would be for another day. Most important is regulating these fans and not being limited by (or having to buy) Cloudline controllers.

Would appreciate some info or perhaps even links to stuff on Amazon etc... I am a bit of an electrical noob but have no problems following instructions, and doing a bit of soldering etc... Cheers!

UPDATE:

Heh told you I was a n00b.... now starting to understand. The optoisolator is essential. What you are doing is using the Pi's native PWM to generate the PWM waveform (or whatever it is called) at 3.3V on some of the GPIO pins. This is going into the optoisolator as PWM input, and is being "applied" to the original 10V output from the molex from the AC Infinity, which then connects to the input molex pins to control the speed.

I see the particular model you used not available on Amazon, but available here: https://www.sparkfun.com/products/9118

I presume these models are pretty much the same (they use the same ILD213T IC, and even look the same):-


Also I think soon I would soon be limited by the PWM channels on the Pi, so would a device such as this be more useful to generate the PWM signals, as it would allow me to control up to 16 devices? https://www.amazon.com/MakerFocus-Resolution-Interface-Compatible-Raspberry/dp/B07H9ZTWNC/ Is this the type of device I need to allow more PWM outputs or is there something better?

Thanks

The optoisolator also PWModulates the 10V. The isolation happens to be an added safety bonus

The Pi has one hardware pwm channel but can also do pwm on nearly any pin thru software. Works great