Zoopaman,Hoot, Anyone-Ever build an Electrobus?

[WillysNut]

I've been experimenting with rheostat controlled fan buses. In my search for additional info and projects out there I found a sweet setup at BitTech that uses a regulator instead of a rheostat to control the speed of the fans.... Electronic vs. Mechanical.

Anyone here ever build one? Just wondering want to get any input, issues, etc. Did you mount the regulator outside of a project box to be sure that heat is dissipated properly? The diagram at BitTech only shows a single fan connection. Could the regulator they shown here (29302-BT) from Micrel, support mutliple fans? Or, Could two regulators run off of a single molex power connection..basically doubling the diagram shown at BitTech.

Working on drawing out what I want to add to the BitTech drawing and will add any additional questions. This level of electronics is a little new to me so please go easy on any newbie statements found above!!

 

[WillysNut]

Here's a picture of the switched electrobus from BitTech.

 

[WillysNut]

This is the setup I would like to use. I believe it's feasible but I'm not sure if each regulator needs an individual power connection?

*EDIT* Thanks for the PM Hoot! Man this place is great!!! The lowdown from Hoot, for those of you interested in doing this:

"I have shied away from the classic 3-terminal regulators due to the fact that you could not get the entire supply voltage out of them. It looks like the regulator you have found overcomes that problem, for the most part. To answer your questions, you can use one of them to control quite a few fans. No need for multiple circuits unless you want to run different fans at different speeds. You can certainly run more than one of those regulators off of the same molex connector coming from the PSU, without any concerns. You definitely want to mount that regulator on a flat surface that can conduct the heat away from it, or even a small heatsink."

Thanks again Hoot!!

 

[Karsta]

Great idea!

I possibly rebuild my rheobus (4 pots and switch to 3 off, 1 on/ 4 on/ bypass for full power) to electrobus with switch and leds.

Did I understand right that with electronic linear control there is no problem with fans turning on with low voltage?

 

[mcrites]

Check this post out from Hoot about voltage regulators:
http://forum.oc-forums.com/vb/showthread.php?s=&threadid=11673&highlight=voltage+regulator

 

[Karsta]

Using only a rheostat also causes a drop in maximum voltage. This is a reason for using a bypass switch for situation when full voltage is wanted.

 

[WillysNut]

I tried this setup with a 3 pin voltage regulator instead of a 5 pin today. The bypass setting is perfect...nice voltage to the fans, but the variable setting did not turn out right...didn't have a 4300 Ohm transitor Tried 3900 and 4700 but neither worked. I could hear the fan motors trying to spin but no go.

Messy setup...just for trying it out...not project box material..

 

[WillysNut]

Well..need to order some resistors, regulators and rheostats....basically everything I got the above setup working by switching to a different mechanical rheostat but I'm not getting enough juice as Hoot mentioned from the regulator in the "variable" setting of the dipswitch....I hate it when multimeters (and mods) are right!!

Another note...The Green LED in "Variable" mode dims and brightens as the voltage to the fan is changed...very cool!!! Parts order in the making...keep everyone posted. Looks like this one is gonna work!!! Final working test schematic..plus a few resistance bugs...

 

[stool]

If you are looking for the Micrel MIC29302BT voltage regulator, you can find them at Newark Electronics , part # 83F5919. they run $4,43 a piece.

 

[zoopa_man]

Cool ! Very nice work. I had a few enermax case fans with regulators built in to them. I couldn't stand it.

The main problem with them was theat the full speed wouldn't kick in. I ended up choping them apart in a evil science experement and they all died. That's when I discovered Rheo's. Havn't had a chance to go back to the electronic switching yet. Too buisy with college...but maybe after my peliter projct that's going to consume most of my spring break i will be able to get back to my case cooling and do something similar to what you have where everything is electronic again.

 

[WillysNut]

Geeze...Stool and Zoopa...you both live in Upstate NY!?! I live in Saratoga Springs. Zoopa..where are you at?..western NY? We gotta all get together sometime...and get Pinky away from AOA long enough to hang!

Damn it's a small world. Stool...you ever hear of Grimmers Electronics in Schenectady? Ever go there? Just heard about it today from a coworker..he thinks they stock most of this equipment...no need for the mailorder wait (I'm so damn impatient)

If either of you guys are ever going to be in Saratoga, PM me and we'll hang! I go to Albany once or twice a week for business and many times on Friday night to hit the town. Let's get some beers and talk shop!!!

 

[stool]

Found Grimmers in the phone book, but hadn't had the urge to travel up there. I do want to check it out, though.

I saw this post and decided to try this out. Ordered about 5 of the regulators, and picked up some pots today. Seeing as I have tons of switches, LEDs, etc., this is actually going to be a cheapie for me.

Usually hit Saratoga frequently during the track, but coincidentally I'll be up there this weekend for a retirement party. I'll PM you this summer when I'm coming up. Be interesting to meet somebody from the forums.

 

[WillysNut]

Let me know how you make out...got some on the way as well! Found another sweet project here. The article is almost a year old. Cant remember anyone mentioning it but it looks really awesome. One more power cord to deal with, but being able to essentially overclock your fans is incredible!

 

[WyrmMaster]

I tried this setup with a 3 pin voltage regulator instead of a 5 pin today. The bypass setting is perfect...nice voltage to the fans, but the variable setting did not turn out right...didn't have a 4300 Ohm transitor Tried 3900 and 4700 but neither worked. I could hear the fan motors trying to spin but no go.

Messy setup...just for trying it out...not project box material..

LOL, you call that messy. Thats what my projects look like when im DONE with them. Any ideas on how to clean them up a bit?

 

[WillysNut]

LOL, you call that messy. Thats what my projects look like when im DONE with them. Any ideas on how to clean them up a bit?

Hehe...I'm really new to this stuff also. I usually do each of these projects twice before anything looks, or at times, works..right. You could always get a bunch of shrink tubing and shorten up some of your lines I suppose!

 

[stool]

Found another sweet project here. The article is almost a year old. Cant remember anyone mentioning it but it looks really awesome. One more power cord to deal with, but being able to essentially overclock your fans is incredible!

Excellent!! I have 2 24vdc blowers I want to use as exhaust from the top of my case, but didn't want to spend a fortune on a DC/DC converter. 22.4v is right up my alley. Power cord isn't a problem, as I have an external setup rigged w/ a relay to power my pump/radiator fan, which just happens to have an extra outlet.

 

[WillysNut]

I tried this setup after work tonight with similar results as above. This setup is supposed to clean and regulate the power a little better but ... The LM317 is very limited in what it can deliver from the Vout pin. The authors of these articles must not have been overclocking too much...they rant and rave about how great these setups are when in fact they appear to be quite weak. Looks as thought the Micrel 5 pin and the above article involving the LM317 are the way to go!

 

[stool]

Got the voltage regulators today, and the first attempt worked like a charm(unswitched version). 120mm GlobalWin slowed to a crawl, just about silent, and cranked up to max. Great control. Switched version will be next.

 

[Colin]

The way to get around the LM317T voltage limits is with a bypass switch for the full 12 volts. Here are a couple of pics of the one I built last year.

 

[Colin]

One more pic.