Fan Tray Mod Question

wildest_jjk · 11 Aug 2013 at 19:12

Hey guys,

I am planning on making a fan tray for the rack I have in the garage but I need some advice.

Basically fan trays that fit into the roof of the rack are pretty expensive so I would like to do my own version really. The plan is to use a piece of MDF and fit some PC fans to it. They would need to be quiet and I was thinking of maybe having about 6.

Can I run these off mains? How about using a fan controller as well? What about adding some sort of temperature sensor to adjust fan speeds?

I'm trying to keep costs down as much as possible but any help will be greatly appreciated

Thanks!

Unicorn · 11 Aug 2013 at 19:32

12v power supply to run something like a bitfenix recon to run the fans, The temperature sensors when using automatic mode on the recon will adjust the fans accordingly. Fans im not sure what would be the best

Tealc · 11 Aug 2013 at 20:44

You can pick up 12v power supplies pretty easily on eBay to power the fan controller. Recon is a good idea as it has 5 individually controlled channels that you could use. Still at £30 it's not going to be cheap.

What about building a fan control circuit based on a NTC thermistor, a few passives and a transistor or two. That would be cheaper.

Something I just sketched up that should give decent results. Might be able top work on 2 or 3 fans given a decent transistor.

paintguy · 11 Aug 2013 at 22:14

Temperature controlled?

I use the 80mm version of these (not in a PC though) and they do a great job. Virtually silent at tick over, even with 4 of them, and still very quiet when the temps increase and they ramp up in speed.

YOUR BASKET
1 x Arctic F12 Pro TC Case Fan - 120mm £4.99
Total : £7.97 (includes shipping : £2.48).

You'd need to find a 12V power supply if you want them running off mains power but they're available just about anywhere.

wildest_jjk · 12 Aug 2013 at 00:30

Thanks for all of the responses.

GrimsbyLAD said:
12v power supply to run something like a bitfenix recon to run the fans, The temperature sensors when using automatic mode on the recon will adjust the fans accordingly. Fans im not sure what would be the best

This sounds like something that would work and I would be interested in. The only problem is cost and I'm not sure how well reviewed that controller is. Does anyone know?

Tealc said:
You can pick up 12v power supplies pretty easily on eBay to power the fan controller. Recon is a good idea as it has 5 individually controlled channels that you could use. Still at £30 it's not going to be cheap.

What about building a fan control circuit based on a NTC thermistor, a few passives and a transistor or two. That would be cheaper.

Something I just sketched up that should give decent results. Might be able top work on 2 or 3 fans given a decent transistor.

Wow thanks for this. I'm really not that experienced with electronics etc though! Would this be worthwhile compared to a controller? Is it difficult to setup?

paintguy said:
Temperature controlled?

I use the 80mm version of these (not in a PC though) and they do a great job. Virtually silent at tick over, even with 4 of them, and still very quiet when the temps increase and they ramp up in speed.

YOUR BASKET
1 x Arctic F12 Pro TC Case Fan - 120mm £4.99
Total : £7.97 (includes shipping : £2.48).

You'd need to find a 12V power supply if you want them running off mains power but they're available just about anywhere.

Something like that does also look very good, there would be no need for a controller or anything. These seem to be the only TC fans available though which is a bit weird. Is there a sensor on a piece of wire or something? Or is it built in?

Thanks everyone!

paintguy · 12 Aug 2013 at 00:43

As well as the main power feed there's a second wire with a temp sensor on it.

They can only be fitted to push air due to the vibration free frame design, and in my application they draw hot air out of the amp rack in the boot of my car. When the system is running at low volume the fans hardly spin and are nigh on silent. When I crank it up and the amps start producing lots of heat the fans sense this and speed up accordingly.

EDIT: I said they could pull air only, I meant push!

Tealc · 12 Aug 2013 at 07:01

wildest_jjk said:
Wow thanks for this. I'm really not that experienced with electronics etc though! Would this be worthwhile compared to a controller? Is it difficult to setup?

That particular circuit gives you the option to trim the low speed (with the 22k trimmer pot in the middle) to your own needs. Not difficult to set up really if you have the available parts and can follow a schematic near enough.

I did quickly test the circuit in Multisim and it works fine there but really would want building on breadboard to analyse the ranges it provides with a proper load (I just used a resistor in aprallel with an inductor to simulate a DC motor. With a suitable output PNP it may well run all 6 fans, if not then you may need two identical circuits with 3 fans each, if you need that many fans. I should also point out that this is just a sketch and it could be improved massively. I would probably not use this method if it were something I was doing. I'd go more into PWM control with a 555 timer based circuit as I have lots of 555 timers and I like the little chip. Also PWM is far more efficient and gives less waste heat.

The Arctic fan with its own temperature thing built in may be easier, although you'll just have to accept its defined fan curve.

wildest_jjk · 13 Aug 2013 at 13:59

Hey guys,

Thanks again for the respones these are some great ideas. I have however found one alternative which I would like to get your advice on.

Basically I stumbled across some digital thermostats. They look something like below:

http://ebayimg.cndirect.com/newcdn/TK/0/TK0128-3-FV88.jpg
http://ebayimg.cndirect.com/newcdn/TK/0/TK0128-5-FV88.jpg
Please don't hotlink pictures

They come in all sorts of different types and cost around £10. There are 220V and 12V. I am guessing the 12V is what I require as I would be connecting fans into them.

There are also different terminals etc on the back of the stat. To be honest I'm not really sure what I need. I'm aware this wouldn't control fan speed but would it at least work based on my needs?

One thing that might be useful is this:

Relay Contact Current: AC 5A / 220V

Again this varies but is this important because it is the power to the fans?

Thanks for all the help

Tealc · 13 Aug 2013 at 15:03

I reckon that is just an on/off solution. So basically your fans will either be on 100% or 0%. You set a threshold temperature. When the device reads above that temperature it engages the relay. Your fans spin. The unit cools to below threshold and fans switch off.

I'd say that's a step back from using a PC fan controller. It's probably mostly for mains powered loads like heaters, motors and the like.

wildest_jjk · 13 Aug 2013 at 15:28

Tealc said:
I reckon that is just an on/off solution. So basically your fans will either be on 100% or 0%. You set a threshold temperature. When the device reads above that temperature it engages the relay. Your fans spin. The unit cools to below threshold and fans switch off.

I'd say that's a step back from using a PC fan controller. It's probably mostly for mains powered loads like heaters, motors and the like.

Thanks again for the response. I do realise this but it's a lot cheaper and would at least turn them off (providing the temperatures are set right).

Would it work at least for on and off?

Thanks!

Tealc · 13 Aug 2013 at 15:55

It should do. The device has a hysteresis setting too so can be adjusted not to just turn on when the temperature is creeping back and forth across the threshold. If you can get them cheap cheap then it might be a decent solution.

The amazing coincidence is that I have 2 very similar (but the mains voltage type made by xxxxx and with two relay output) devices on my desk that have been hidden under a desk for 3 years.

wildest_jjk · 13 Aug 2013 at 16:45

Tealc said:
It should do. The device has a hysteresis setting too so can be adjusted not to just turn on when the temperature is creeping back and forth across the threshold. If you can get them cheap cheap then it might be a decent solution.

The amazing coincidence is that I have 2 very similar (but the mains voltage type made by Elreha and with two relay output) devices on my desk that have been hidden under a desk for 3 years.

That is quite a nice little feature. To be honest as long as they are quiet and aren't on all the time I think it's pretty much what I need. For £8-£10 I guess you can't really go wrong.

Does that mean you have the 220V if it's mains? Would I be able to wire 2 fans into it? Or would I need one with two relay outputs as well?

I am thinking of getting 1 or 2 200mm fans seeing as they are quieter.

Thanks again.

Tealc · 13 Aug 2013 at 17:36

I believe that the mains voltage is just for the device itself. The model I have here at home (now that I brought it home) is a. Inside it has a bridge rectifier and a transformer along with some regulators and a big 10A and 16A relay. Relays are just like switches and should remain separate from the rest of the circuit. So if this is true then just breaking the power wire to the fan and wiring it through the relay points should allow the device to make or break the power based on the temperature.

I may have one of the temperature probes in my garage drawer so might have a play with this thing tomorrow, rather than just harvest it for spare parts.

wildest_jjk · 13 Aug 2013 at 19:45

Thanks again.

So I could get a 12V or 220V thermostat? Just depends whether I want to power it off of mains or an adapter?

If the relay contact has higher amperage than what the fans will be using does that matter?

Thanks

Tealc · 13 Aug 2013 at 21:18

The amperage rating is just a maximum. If you'd like I will send you one of mine if they work and if I can find the thermistor. Would need the postage covered that's all.

wildest_jjk · 13 Aug 2013 at 22:00

That's a really kind offer. Does it function the same as the one I was talking about? In terms of features.

Thanks!

Tealc · 13 Aug 2013 at 23:09

Will find out tomorrow when I hook it up to the mains and some fans.

wildest_jjk · 13 Aug 2013 at 23:13

Thanks very much

One other thing is surely it needs to be DC 12V or else it won't power the fans?

I am probably wrong though.

Tealc · 14 Aug 2013 at 06:56

You will still need to power your fans by some means, possibly a plug in 12v power supply from ebay or something. This thing is just a fancy temperature based on off switch which can handle large switching loads. It is total overkill for your needs of course but it'll look tidy once installed.

I'm thinking of using one as a temperature reading for a DIY fan controller.

Edit: Hmm I do have a probe in the garage but I've no idea if it is the correct 2k PTC that the device requires. Will have to check it out. A lot of the temperature sensors used are NTC but these devices are used in refrigeration and heating so need to cover lower temperatures. These things are next to useless without the correct probes and all I have is the devices at the moment.

wildest_jjk · 14 Aug 2013 at 11:22

Tealc said:
You will still need to power your fans by some means, possibly a plug in 12v power supply from ebay or something. This thing is just a fancy temperature based on off switch which can handle large switching loads. It is total overkill for your needs of course but it'll look tidy once installed.

I'm thinking of using one as a temperature reading for a DIY fan controller.

Edit: Hmm I do have a probe in the garage but I've no idea if it is the correct 2k PTC that the device requires. Will have to check it out. A lot of the temperature sensors used are NTC but these devices are used in refrigeration and heating so need to cover lower temperatures. These things are next to useless without the correct probes and all I have is the devices at the moment.

So the power that is going to the thermostat will not power the fans? It will need an external power source?

Sounds pretty cool, would you be using something like the circuit you posted above?

Not to worry if you cannot find the probe, don't want to cause you any extra hassle

Thanks for all the help.