High Draw 12cm Fan (Smart Opinions Needed)

[ToddTheFrog]

FIRST POST! I think I've found a new home (HardForum convert here)

OkeeDokie I found a badass 12cm fan that i want to put on a heatercore but its specs say:

130 CFM @ 3500 RPM. 12 Vdc, 1.2 Amp. 49 Dba

Now thats way too loud but its good to have that much power if I need it. I have a two part question here. How hard would it be to design a Fan Controller that will lower from 0 to 12V and can a powersupply even handle two of these on top of the normal mid to top-of-the-line system? Now heres the really hard question. What I want to do and I will definately need help with is ...

If i power this thing at say 5 or 6 volts there is no way that it's going to start up when the system boots. What I am thinking about doing (if this is even possible) is make some type of circuit that will momentarily power the fan with 9 volts to start it up then drop down to whatever voltage the controller is set at after a very short time (maybe 3 or so seconds).

All help is greatly appreciated guys!

Todd Trowbridge

[bigben2k]

Welcome!

Google for Rheobus. Otherwise you'll need some knowledge of electronics to make that mod.

A PWM controller might serve you better here, but it'll be a bit more pricey.

[ToddTheFrog]

Originally Posted by bigben2k

Welcome!

Google for Rheobus. Otherwise you'll need some knowledge of electronics to make that mod.

A PWM controller might serve you better here, but it'll be a bit more pricey.

I've looked into rheobus's (not a noob here hehe) but none can handle this much amperage.

[Butcher]

1.2A isn't that much current really, You should be able to run two of those off an ATX psu without any issues.

[Cptn. Foo Foo]

Originally Posted by ToddTheFrog

How hard would it be to design a Fan Controller that will lower from 0 to 12V

You could make a simple LM317 based controller.

Like this one...http://casemods.pointofnoreturn.org/...rial-full.html


Here is a pic of the fan controller I made. It doesnt connect to the ATX power supply though. Rather it is connected to a 12.6v transformer rated for 3 amps. My controller has to deal with A/C power from the transformer whereas the one linked above doesn't.

Right now this controller is running three 120mm fans (sorry I cannot remember the exact power draw for each). I do know that the fans are rated around 100 CFM each @ 12v.

(this pic I somewhat old as I have changed the heatsink on the LM317 to something bigger)

[AntiBling]

On my PC, a delay timer fires a relay two secs after start up. Before the relay is fired, it sends 12v to my fans. When the relay engages it changes the fans supply line to one that is resistance adjusted by a pot as a speed control. This gives good starts and a low final speed. Just another way to do it...

Sounds crude but its worked that way for quite some time now. The trick is to select the right size pot for a good range of adjustment. Trial and error is fine for that since they are just a dollar each at surplus stores.

[Cyco-Dude]

have you actually tried powering the fan with 5 or 6 volts to see if it will start up? you wont know unless you try.

as far as the fan controller goes, you'll have to see what the max amperage per channel is. for mine, its 1.5 amps. i would think that most quality rheobuses would be able to handle those fans without any issues. Power (watts) = Voltage * Current. so with 12 volts going to your 1.2amp fan, you'll need a controller that can handle at least 14.4 watts per channel (and most can). when in doubt, email the manufacturer.

[Brians256]

Welcome to ProCooling!

Also, some PWM fan controllers have a hard time with larger draw fans. See if you can try before you buy, or get a mfg promise as Cyco-Dude suggested.

[ToddTheFrog]

Thank u guys a lot for the quick responses. You've helped a LOT

Todd Trowbridge

[TerraMex]

Here's a thought.

A PWN can be used with just about circuit. Right? Right.
On the PWM exit, use a power transistor . TIP32 for an example. Rated 3A.
Feed the base with the PWM signal, you'll get a shitf between active and cut zones within a certain frequency limits. The transistor must have a good response time. He'll reproduce the wave (with a slight deformation) , but the current will only depend on the power transistor itself and the power supply.

[Brians256]

Originally Posted by TerraMex

Here's a thought.

A PWN can be used with just about circuit. Right? Right.
On the PWM exit, use a power transistor . TIP32 for an example. Rated 3A.
Feed the base with the PWM signal, you'll get a shitf between active and cut zones within a certain frequency limits. The transistor must have a good response time. He'll reproduce the wave (with a slight deformation) , but the current will only depend on the power transistor itself and the power supply.

It should work. Watch the inductive spike though.

[Blackeagle]

Sunbeam's reobus, 20 watts per channel & it goes from 0=12v on all 4 channels.

Will handle 4 of those Deltas you have there.

[Butcher]

Originally Posted by Brians256

It should work. Watch the inductive spike though.

Easily fixed with a diode

[ToddTheFrog]

Originally Posted by Blackeagle

Sunbeam's reobus, 20 watts per channel & it goes from 0=12v on all 4 channels.

Will handle 4 of those Deltas you have there.

Is this solid information? If so thank you VERY much, I'm getting this one.

Todd Trowbridge

[Cyco-Dude]

Originally Posted by ToddTheFrog

Is this solid information? If so thank you VERY much, I'm getting this one.

Todd Trowbridge

yes. these are simply rebadged PCmods rheobuses. you can buy these with clear anodized knobs and red LEDs for $13.99 from http://www.pcmods.com/
you have to drill your own faceplate though (the sunbeam comes with one pre-drilled).

[Blackeagle]

Originally Posted by Cyco-Dude

yes. these are simply rebadged PCmods rheobuses. you can buy these with clear anodized knobs and red LEDs for $13.99 from http://www.pcmods.com/
you have to drill your own faceplate though (the sunbeam comes with one pre-drilled).

While the Sunbeam and pcmods reobuses share the same 20 watts per channel rate from the two makers, I disagree with your assertion that the Sunbeam is a remarked version of the pcmods unit.

Fact is Sunbeam makes a number of differant mods, and all are top quality.

Frankly just reading the info on the two reobuses I think the Sunbeam is the better quality unit, with some small, but added features. Note that on the Sunbeam each channel can be turned off, or up to 12v. The Sunbeam also comes with a nice brushed aluminum face plate & dual color LEDs. And at 14.99 at SUV the Sunbeam is the better value.

[Cyco-Dude]

Originally Posted by Blackeagle

While the Sunbeam and pcmods reobuses share the same 20 watts per channel rate from the two makers, I disagree with your assertion that the Sunbeam is a remarked version of the pcmods unit.

Fact is Sunbeam makes a number of differant mods, and all are top quality.

Frankly just reading the info on the two reobuses I think the Sunbeam is the better quality unit, with some small, but added features. Note that on the Sunbeam each channel can be turned off, or up to 12v. The Sunbeam also comes with a nice brushed aluminum face plate & dual color LEDs. And at 14.99 at SUV the Sunbeam is the better value.

i wonder if sumbeam manufactures them for pcmods? the boards are exactly the same.

yea, the sumbeam does have a few minor extras.