My Stirplate... Cheap and Easy Build...

Just built one! so far so good!

I tried to make it with a mosfet from a drill ESC but I couldn't figure out how to wire it. It was working more like an on off switch.

One trip to radioshack and we are stirring!

The only issue is I have little control for low RPM. I think I need a giant resistor.

 

She's a mother beautiful stir plate baby!

 

So last night I hooked up a 9V battery to the fan leads, and the same thing happened. The fan blades spun about 5-degrees, then locked up. I couldn't turn the fan with my finger. Then I disconnected the battery, and could spin it just fine. Can I conclude that this fan is friend internally?

 

It sounds like the magnets for your stir bar are overcoming the magnets in the motor. Did you use some sort of spacer plate to isolate and space out the drive magnets from the motor magnets/windings?

 

I haven't installed any magnets on the fan yet - literally just the fan by itself, bare leads, hooked up directly to a 9V battery.

 

Have you tried to power it with anything stronger than a 9v battery? Could be that it is just way underpowered.

 

Did you try the wires both ways on the 9v battery?

 

yeah - both ways - no dice. I returned it tr Radio Shack tonight and the guy hooked it up to a 12V supply in the shop and confirmed it was ruined. Swapped it for another one so we'll see what happens.

 

So after all my work building my PWM board I hook it up and o got 3+ volts. Arggg! I can't figure why my 555 chip is shedding 2volts?

 

I think this has been posted but I can not find it... How would the 8 amp work with a fan as a modulator?

http://www.amazon.com/gp/product/B003L4KKF2/?tag=skimlinks_replacement-20

Or how about this bad boy?

http://www.amazon.com/gp/product/B002PNFEM4/?tag=skimlinks_replacement-20

I am tired of bread boarding and want to get spinning!

 

Well after some trial and error I finally got my stir plate to work. I was able to stack three washers and four hdd magnets on top of each other centered in the middle of the fan. I use a old Dynex case fan and was able stir a 5000ml flask with a 2 inch stir bar with a medium size vortex. I'll post some pictures when I get time. Thanks for everyone's help.

Z

 

I'm going to attempt to build one of these in an old pelican case. Does anyone see a problem with the plastic being about 1/8" thick on the top. Will my rare earth magnets be strong enough through that?

 

To loosely quote other members, build it and show us what you made! Only trial will tell how it works

 

Got everything but the fan, will build on Tuesday. I did have an old broken printer that I stripped for parts (wire) and got two small motors that ran the ink cartridges back and forth. I wonder if I could hook them up to the power source and fix a blade for the magnets on it. I think I'll try it while I wait for the fan and research more info about the motors.

 

Here's he fan/rare earth stirrers I have built. Check em out if you need one, I got four.

 

I would shoot for 500-1500 rpm in whatever you build.

 

This is the 9.99 build. I paid less than that, but with buying all parts, it would be 9.99. CD-R 50 pack spindle top as the bsae for this model.

 

So the motor in the printer is 12-42V, output 3-65W and 6300 rpm. Info here:http://www.compucanjes.com/manuales/RS_455pa.pdf

I assume it's way too powerful, but I want to play with it anyway. My question is, will the 30a 12v rocker and 25 ohm Rheostat and my phone charger power this thing. I'm very green to all of this and don't want to be unsafe. Power supply is input: 120vac out: 9vac.

I realize this I'm hijacking this thread a bit.

 

It doesn't sound like your cell phone charger will do the job. It only outputs 9 volts and the motor needs at least 12.

 

You also need to match up amps which is what will drive the motor. You typically can under volt it a bit but you need the amps on the power source to match.

 

Many of us are 'undervolting" our 12v motors to get the right speed and control range of the fan for a stirplate. I have one running 9.6V and another at 12V. The 12v plate will throw a small stirbar or even the big one in a small starter.
Interestingly, I was replacing an 80mm fan in the power supply of my wife's computer last night. The new fan's motor specs stated 12v with a 6v minimum startup voltage. So I don't see any reason this fan can't be run anywhere between 6 and 12V+ (normally DC motors need full voltage for startup, and then can be turned down after start)

 

I think your biggest problem is that the cell charger output is AC not DC

 

Amp output is far more important than voltage honestly unless your talking about tiny voltages. There are motors that won't turn over with less than the rated volts but that isn't typical in my experience. Also, most wall warts I've seen rate their volt output versus expected load. IE I have a 10v that runs near 14v. You can test by wiring a 9v in series if it doesn't work and you think the voltage is the problem tho.

 

I have 2 other power supplies available. 1) Output 4.9VDC 450 mA & 2) an old external HD that has two dc output ratings 5v - 2 A; 12V - 2.2 A

 

I appreciate what you are trying to accomplish with using what you have. Can I just say from my experience in the DIY stir plate that having to match things like mili volts and amps with rpms and all the other variables is an absolute pain in the uterus! Unless you are a electric nerd that goes to robot wars I would strongly suggest the simple approach and buy a Fan like this
http://www.amazon.com/gp/product/B002OJN250/?tag=skimlinks_replacement-20
The knob is relocatable and all you need is a USB wall wort and you are spinning!

 

Here is someone who did the same thing

 

I built my pelican case stirplate last night. I went with the computer fan for now. Its pretty beefy but I think its awesome.

I still laid in bed last night thinking about that little motor and what I could do with it. This was my first foray into DIY electronics, albeit an extremely easy one. I had a blast and want to build something else now.

 

pic please!

P.S. I love pelican cases.

 

I'll post one when I get home tonight.

 

Pelican Case stirplate. I replaced the air vent with the potentiometer.




SWMBO approves!

 

Volts are typically only necessary to be in the ballpark (and not above) and a little lower is probably better anyway and with most fans 12v that is absurdly easy. Amps are the most important to match or exceed with your power supply. If you'd struggle to do either of these and your going to spend that kind of money, why not spend the extra $10-20 and get one with a good warranty and not mess with it at all?

 

Bravo! Any issues with magnetism due to the thickness of the awesome case?

 

None yet. Although I have no frame of reference with this being my first and only stirplate experience. Seems to get a near 2 L of water going just fine with a couple inch deep vortex.

 

Another stir-plate gets its spins!

<--Video

 

Simple design. Computer cooling fan, old phone charger, switch and cigar box. Works great.

 

Why do you set the flask right on the fan instead of closing the lid?

 

Hi,

I am currently working a variation of this build, using a cigar box for a project box and magnets that I got from work. For now I just had the fan wired a 5v cell phone without the rocker switch and rheostat hooked up while I was trying different configurations with the magnets. I am using small round 1/2" diameter magnets that I got from work, they are very strong.

Several days after I mounted the magnets, my fan suddenly does not work. It had been working great, but now when I plug it in it spins very weak a couple revolutions and then stops. Is is possible that my magnets were too strong and demagnetized the fan motor?

I will post a pic when I get a minute.

 

I checked my wiring and that all looks good, any help would be appreciated.

 

Belay my last. I gave the fan a few spins while plugged in and it took off and it's working fine now. Still not sure what the problem was.

 

Not sure if your fan came from an old computer, but if it was like mine, it probably had several years of accumulated ghost turds built up in the housing. Works like charm, though!