Help With Stir Plate Please!

So following instructions from the My Stirplate... Cheap and Easy Build I obtained all the parts from Radio Shack I would need.

I had a Nokia cell charger lying around (5.7V 800mA) that I stripped the wires too and connected as in the tutorial, but when I turn on the switch, the fan doesn't move. If I adjust the potentiometer the fan spins as I'm adjusting it, but doesn't spin otherwise.

Any help would be appreciated.

Here's the connections:




The Charger has the Red and White wires (I assumed white was ground) and the fan (it's a 0.16 A 1.9W 3" fan from radio shack I had lying around) had red and blue wires (again, assumed blue was the ground).

So I connected the Blue (from the fan) and the White (from the charger) together and around the Earth terminal on the switch.

I connected the Red from the charger to the Load on the Switch, then a green wire from the Supply on the Switch to the middle terminal on the potentiometer, and then the Red from the fan to the "right" hand terminal on the potentiometer.

Did I get something backwards? Do I not have enough juice?

Any help is appreciated!

Also, the solder on the green wire is horrible, I know . It's been a while. It does NOT, however, touch the Earth terminal on the switch. That's merely an optical illusion.

Not enough voltage IMO. When soldering lugs like those with the holes in them I put the wire through and wrap it back on itself before soldering. You should be able to test it without actually soldering the wires, then when you have it right you can make it a permanent connection.

I also think that your power supply isn't supplying enough voltage. I am assuming your fan is a 12V fan. If that is the case, a 5.7V power supply won't provide enough juice to get that fan spinning. I built my stirplate using the same basic components, but I got a variable voltage power supply from Radio Shack. It can be set between 3 and 12V at 1.5V increments. I find that setting mine at 9 or 10.5V usually does the job. It just depends on what kind of speed you would like to run the fan, and how strong your magnets are.

I got my magnets from the inside of a magnetic aquarium scrubber. They are quite strong, and I can now run my stirplate at full power without throwing the bar. I don't need that much power to maintain a vortex to the bottom of the flask, though.

Power supply would be my first guess... Be wary of those switches as well... Mine pooped out yesterday... Just hot wired it through for the time being...
Good luck!

Thanks for the tips guys. I'll try to up the voltage and see if that does anything -- totally makes sense. It's been a long time since 9th grade science!

I get cheap used power supplies from a bin in the local goodwill store...

I connected the Red from the charger to the Load on the Switch, then a green wire from the Supply on the Switch to the middle terminal on the potentiometer, and then the Red from the fan to the "right" hand terminal on the potentiometer.

Did I get something backwards? Do I not have enough juice?

Click to expand...

Your Load and Supply is backwards. Supply should go to your power source and Load should go to the Pot.