Noctua 24v to apparently 12v psu

[Sgt. Hippie Cat]

I was thinking of picking up the noctua industrialppc 2000rpm fan, i was searching around on forums and found that if i molex'd it into a power supply i could get the full 24v, just without any speed adjustments. however looking at my power supply spec sheet (seasonic prime titanium) it only supported a 12v rail. am i missing something here?

https://seasonic.com/prime-ultra-titanium#specification

https://www.hardwarebbq.com/industrialppc-nf-f12-and-nf-a14-24v-pwm-fans-review/all/1/

 

[Ben17]

4 minutes ago, Sgt. Hippie Cat said:

I was thinking of picking up the noctua industrialppc 2000rpm fan, i was searching around on forums and found that if i molex'd it into a power supply i could get the full 24v,

no that psu doesn't seem to be able to do 24 volts

[DoctorNick]

Haha they work from 6-30v, so yes they work at 12v at max 1600rpm- source https://noctua.at/en/nf-f12-industrialppc-24v-3000-ip67-pwm

 

Also 12v@2amps = 24v@1amps

[mariushm]

44 minutes ago, DoctorNick said:

Haha they work from 6-30v, so yes they work at 12v at max 1600rpm- source https://noctua.at/en/nf-f12-industrialppc-24v-3000-ip67-pwm

 

That fan is designed to function with a wide voltage range, so you can power it from 12v, but it will run at lower rpm.

Don't mess with the power supply.  While in theory you could replace the ground with the -12v of your power supply to get 24v between positive and negative, most power supplies can only do up to 0.5A ..1A on -12v, and if there's some problems with the fan like blades seizing or something, the power supply could be damaged.

 

If you want 24v, get a boost regulator, a dc-dc converter which takes 12v and raises it up to whatever voltage you want. eBay has plenty of these, here's an example: https://www.ebay.com/itm/DC-DC-Boost-Adjustable-Step-Up-Volt-Regulator-Converter-2v-24v-To-5v-12v-24v-2A/323236694668

If you do decide to use one, make sure the bottom of such board doesn't touch the case or any conductive surface (put it in a cardboard box, or use heatshrink on it leaving just the potentiometer knob out)

 

The fan says it consumes 4.32w (24v at 0.18A). A voltage regulator like the one above would be safe to up to let's say 0.75A..1A

 

44 minutes ago, DoctorNick said:

Also 12v@2amps = 24v@1amps

No, it doesn't work quite like that unless it's a purely resistive load. You can't generalize it.

If there's some conversion process, there's always gonna be some efficiency losses, the conversion will be 90-95% efficient at best.

This being a three phase motor with a control circuit that advertises 6v..24v operation, the mosfets that turn on and off inside the controller will probably be less efficient at 12v but the differences will be very small... and so on and so forth.

 

[DoctorNick]

18 hours ago, mariushm said:

That fan is designed to function with a wide voltage range, so you can power it from 12v, but it will run at lower rpm.

Don't mess with the power supply.  While in theory you could replace the ground with the -12v of your power supply to get 24v between positive and negative, most power supplies can only do up to 0.5A ..1A on -12v, and if there's some problems with the fan like blades seizing or something, the power supply could be damaged.

 

If you want 24v, get a boost regulator, a dc-dc converter which takes 12v and raises it up to whatever voltage you want. eBay has plenty of these, here's an example: https://www.ebay.com/itm/DC-DC-Boost-Adjustable-Step-Up-Volt-Regulator-Converter-2v-24v-To-5v-12v-24v-2A/323236694668

If you do decide to use one, make sure the bottom of such board doesn't touch the case or any conductive surface (put it in a cardboard box, or use heatshrink on it leaving just the potentiometer knob out)

 

The fan says it consumes 4.32w (24v at 0.18A). A voltage regulator like the one above would be safe to up to let's say 0.75A..1A

 

No, it doesn't work quite like that unless it's a purely resistive load. You can't generalize it.

If there's some conversion process, there's always gonna be some efficiency losses, the conversion will be 90-95% efficient at best.

This being a three phase motor with a control circuit that advertises 6v..24v operation, the mosfets that turn on and off inside the controller will probably be less efficient at 12v but the differences will be very small... and so on and so forth.

 

In this case you can use the fans on both 24v or 12v, becuase it's listed in the specs. They may be less efficient, but who cares. Also if it wasn't designed to run at 12v also, they would put a warning on the specs/product page? But if it matters, get the 12v version.