PWM Stir Plate Plans

[HenryVance3]

I am throwing the larger stir bars does this have to do with my magnet placement?
Do you use stir bars with the ring in the middle or not?

 

[xjncoguyx]

Wow, you guys went way fancier than me on the stir plate. I went simple, and it works awesome.

Make your own Stir Plate « « Love Brewing CompanyLove Brewing Company

 

[ianw58]

I realize this an older thread, but, in the hopes that one of you guys are still tracking this...

I just got a PWM controller off ebay...

http://www.ebay.com/itm/251356345922?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

I hooked up a fan directly with my 12v wall wart DC power plug to make sure the fan was working. The fan ran just fine.

I hooked the power to the controller and then wired to the fan to make sure the controller would work before I put it all on a nice box.

As soon as I applied power, I smelled buring electronics and saw a puff of smoke from my fan. WTF?

It's been a long time since I putted around with electronic circuits, but I'm not understanding what happened.

Before I buy a brand new fan, could someone help me understand what I did wrong, please?

Thanks for your help!

 

[MikeYoung]

The fan, not the controller, fried? Pretty neat trick... Sorry, I have no ideas to help you.

 

[raouliii]

Either something is wrong with the controller, or the components were mis-wired. A photo maybe? Photos of the data plate of the fan and power supply? Instructions for the controller? The photo of the controller bottom indicates simple wiring.

 

[day_trippr]

I built a pair of stir plates using that same PWM module and they work great.
I use 1/2 liter, 2 liter and 5 liter flasks with 1" and 2" stir bars and can dial from "dimple" to "tornado" on any of them.

Either a miswire (seems unlikely) or you were unlucky and received a defective module...

Cheers!

 

[jsguitar]

Those are some seriously nice DIY stir plates daytripper! Nice work.

 

[TimelessCynic]

I found a nintendo enclosure to be perfect when building my stir plate. I don't have any special components inside. No potentiometer or anything. I just use a 16 volt computer power supply and it spins my 12 volt computer fan sufficiently fast. I like the nintendo cause it has internal parts like a power button and power receptacle that can be soldered to. It looks bad ass as well.

 

[ianw58]

I tossed the fan after it smoked. It was a rescue from some electronics. It was a 3" Chinese model.

Here are some photos...

 

[ianw58]

Next photo...having trouble uploading multiple photos...

 

[ianw58]

Next photo...

 

[Wynne-R]

If you smoked the fan, you have way more than 12 volts. Bad power supply.

A voltmeter would be helpful.

 

[ianw58]

Having trouble with photos on the iPad. Will jump to the laptop shortly.

Checked the voltage out on the PWM board. 12.3v with pot thrown to right. 11.9v with pot thrown to left.

Although it's only 0.4v difference, I thought the voltage out of the PWB should be stable but the pulses of power out change with the throw of the pot.

Is it possible to wire the fan backwards? ie - + to - and vice versa.

 

[ianw58]

Here's the meter readings...