What happens when...

[mspiredm3]

You connect a fan that draws slightly more watts than you fan controller is rated at?

Looking to use this fan on a 30 watt fan controller, what would happen?

http://www.frozencpu.com/products/9...21038_CFM_QFR1212GHE-PWM.html?tl=g36c435s1109

 

[EarthDog]

It will get hot and possibly burn out earlier than if it wasin spec. Who knows how long it will last.

BUT thats sasying you are running this thing at full tilt too.

 

[mspiredm3]

It will get hot and possibly burn out earlier than if it wasin spec. Who knows how long it will last.

BUT thats sasying you are running this thing at full tilt too.

So I can run it, and just keep it like 5% from full load and that should be fine? I mean, I will probably run that fan at full speed maybe 1% of the time. Looks like I will give it a shot

 

[EarthDog]

That thing is goig to be so loud...LOL

 

[mspiredm3]

That thing is goig to be so loud...LOL

Even ran really low? like at 7v?

 

[EarthDog]

It wont be terrible, but will be louder than most fans for sure. You sure you need such a monster? I mean you breaking air cooling records or something?

 

[mikeyw]

Can you use a voltage regulator for a PWM fan?

 

[mspiredm3]

It wont be terrible, but will be louder than most fans for sure. You sure you need such a monster? I mean you breaking air cooling records or something?

On lower voltages, it couldn't be louder than the Antec fans that came with the Kuhler. Hmmm, you got me thinking, maybe I should go with the 5400rpm Gentle Typhoons. I want a San Ace fan, but they are so hard to find.

Not looking to break any records. You see, I have this disease... I have to have the best of things, and its fun and relatively cheap to play with some high power fans

 

[mspiredm3]

Can you use a voltage regulator for a PWM fan?

I was under the assumption that you could, but could very well be wrong. Anyone?

 

[Jaydu]

you will blow out the pot on the fan controller.

 

[JigPu]

So I can run it, and just keep it like 5% from full load and that should be fine? I mean, I will probably run that fan at full speed maybe 1% of the time. Looks like I will give it a shot

Perhaps I'm just being stupid (it certianly wouldn't be the first time), but I'd think running the fan at full tilt would be easiest on the fan controller. At full speed the fan should be dropping almost the entire 12V. The fan controller isn't perfect so it will drop some voltage on its own, but even if it dropped one volt (leaving the fan at 11V) you're still only talking 1V * 2.7A = 2.7W of dissipated power.

Really, I'd be more worried about stall conditions than anything else. When stalled, the fan draws much more current than when running since it is producing no back EMF. Though stall conditions should only persist for a fraction of a second, its anyone's guess as to whether the controller could handle it. Unfortunately, there really isn't any good way of putting on number on that "much more" without getting the fan, feeding it 12V, stalling it by hand, and measuring the current draw...

JigPu

 

[Bobnova]

Perhaps I'm just being stupid (it certianly wouldn't be the first time), but I'd think running the fan at full tilt would be easiest on the fan controller. At full speed the fan should be dropping almost the entire 12V. The fan controller isn't perfect so it will drop some voltage on its own, but even if it dropped one volt (leaving the fan at 11V) you're still only talking 1V * 2.7A = 2.7W of dissipated power.

Really, I'd be more worried about stall conditions than anything else. When stalled, the fan draws much more current than when running since it is producing no back EMF. Though stall conditions should only persist for a fraction of a second, its anyone's guess as to whether the controller could handle it. Unfortunately, there really isn't any good way of putting on number on that "much more" without getting the fan, feeding it 12V, stalling it by hand, and measuring the current draw...

JigPu

This is what I was going to post.
Stall conditions and almost-but-not-quite full speed are likely to be the worst.

Don't do it.

 

[muddocktor]

The startup current of that beast will kill your fan controller, as startup surge will pull 1.5-2 times running current. And believe me, you really don't want the GT AP-31 fans either for 24/7 use. They are way too noisy at full speed to ever keep them there for more than an hour or 2. I know, since I have a couple I use for heatsink testing.

As for San Ace fans, you can find them if you know where to look. Newark.com stocks them. I would suggest some 9G1212H101 fans, which move around 100 cfm and aren't unbearably noisy. If you are running off a fan controller, you don't need a PWM fan anyways.

If you do want a truly outrageous fan, you might want a San Ace 9CR1212P0G03 instead of that wimpy Delta you linked.

 

[mjw21a]

Why not go with a Delta fan which draws power straight from the PSU and uses a separate connector to control fan speed? That negates any issues you may have. I'm running these:

http://www.ebay.com.au/itm/140567023940

I don't understand why people keep wanting to run uber powerful fans off mainboard headers. Seriously, you'll kill the headers. Do the smart thing and run the fan straight from your power supply.

I may be going deaf, though I really don't think these things are overly loud. They're not loud enough to trigger my microphone in Teamspeak while gaming and thats the main thing. Of course, choice of headset is important with this. Plantronics headsets rock for not picking up every little bit of background noise.

Lol, that 300CFM Sanyo Denki looks nuts. I would though it looks like they won't fit in my case, and I'd probably end up deafer than I am now..... I'd also be concerned about killing my PSU, that thing is a monster!

 

[JigPu]

This is what I was going to post.
Stall conditions and almost-but-not-quite full speed are likely to be the worst.

Don't do it.

Somewhere around 6V should be a worst case since the voltage drop is high and the current is non-negligible. That said, I don't think it would really pose much of a problem. Even if the fan drew the same amount of current at 6V as 12V, we're still only talking about 6V * 2.7A = 16W. Since current will actually decrease with decreasing voltage, any "running" speed should be easily handled by the controller.

...unless I misunderstand fan controller ratings... I haven't used one before (yay resistors and 7V mods!), but the pictures I see online (e.g. this) don't really look like they have enough heatsinking to handle 30W of dissipation per channel.

JigPu

 

[Bobnova]

I spent some time testing a fan controller, as the voltage to the fan drops the currant drawn by the fan drops as well. That, of course, assumes that a high power delta acts the same way as a 0.25a 120x25mm fan, which is what I tested.

 

[ehume]

PWM fans can be controlled by reducing their Voltages.

You must always consider the startup current draw for each fan. The startup Amps can be twice as much or more than the running Amps.

Even if you intend to start it at a low speed, if just once you forget, or someone turns a knob, or a cat paws it . . .

Better safe than sorry.

 

[muddocktor]

Thank you for repeating what I stated above about starting current, ehume. Looks like nobody else thought it meant anything besides you.

I have actually checked this on my Sanyo Denki Beast. Running at full speed, it draws 6.3-6.4 amps. When starting though, my cheap dmm showed surge currents of around 8-9 amps and my cheap meter isn't very responsive, so I know actual startup surge was well past that point.

 

[mspiredm3]

I just went with two of these

http://www.newark.com/jsp/search/productdetail.jsp?SKU=96M7077

We'll see what happens at startup.

 

[ehume]

Thank you for repeating what I stated above about starting current, ehume. Looks like nobody else thought it meant anything besides you.

I have actually checked this on my Sanyo Denki Beast. Running at full speed, it draws 6.3-6.4 amps. When starting though, my cheap dmm showed surge currents of around 8-9 amps and my cheap meter isn't very responsive, so I know actual startup surge was well past that point.

I was skimming. Missed your post. Sorry about that.

Examples abound. With a Gentle Typhoon AP-15, the running draw is 83mA. You could power 12 with a 1A header. But the startup draw is 360mA. Oops.

I just went with two of these

http://www.newark.com/jsp/search/productdetail.jsp?SKU=96M7077

We'll see what happens at startup.

Holey moley! Under $20 for an aluminum frame San Ace. The low price makes up for having no rpm-reporting line (that's what the -02 means at the end of the product number). 4800 rpm and only 57 dB. 180 cfm. A real brute of a fan. 1.9A.

Do let us know what you draw on startup. I wish Sanyo Denki listed that parameter.