DIY stir plate question

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Coppinburgh

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I'm looking to put together a stir plate so I can begin using yeast starters. Picked up this fan from work and apparently its 115 volts. Is this too much fan?? I don't have much more than absolute basic understanding of electrical and voltage

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I don't have much more than absolute basic understanding of electrical and voltage
It might be safer to use a 12V or 5V computer fan and power it with a wall wart, those little power supplies you simply plug into an outlet. You can connect to the fan wires by simply stripping the wires, twisting them together, and wrapping with electrical tape.

If you make a mistake with 12V, you might get a little tingle. If you make a mistake with 120V, the results can be dramatic in several ways.

If for some reason you plan to go with 120V and a dimmer switch, then ABSOLUTELY put the dimmer switch in a junction box. It is designed to hold all the wire connections safely.
 
I wouldn't be scared of 120V, but you do have to take the usual precautions. I'm not sure a dimmer switch is the way to go. I don't think they work on electric motors the way they work on lights. Might be you just need the correct type of electric motor.

That said, 12V fans are a dime a dozen and lots less of a bother to play with. You can control the speed with a very simple, or very cheap, circuit you can build or buy. Or just run a lower voltage, say like 6V-9V. I've used a volume pot to control my original stirplate and I built a PWM circuit to control a newer model and both worked fine. The PWM curcuit allows for more speed range and finer control, but a decently built stirplate shouldn't need all that control.
 
I wouldn't be scared of 120V, but you do have to take the usual precautions. I'm not sure a dimmer switch is the way to go. I don't think they work on electric motors the way they work on lights. Might be you just need the correct type of electric motor.

That said, 12V fans are a dime a dozen and lots less of a bother to play with. You can control the speed with a very simple, or very cheap, circuit you can build or buy. Or just run a lower voltage, say like 6V-9V. I've used a volume pot to control my original stirplate and I built a PWM circuit to control a newer model and both worked fine. The PWM curcuit allows for more speed range and finer control, but a decently built stirplate shouldn't need all that control.


Good info, but they make variable speed controls for ye olde ceiling fans, which will work on that 110 volt muffin fan.:mug:
 
Today is the day for stirplate questions. I tried a variable speed fan adjuster on my stirplate and it just turned the fan off and on. Your better off with a potentiometer from RadioShack ( yes they are basically the same) but you can find the exact voltage reduction you want to use.
 
My stirplate is made with a similar 115V fan and a stripped cell phone wall wort from Goodwill. I just put a resistor inline between the hot lead of the power and the fan. Does the job and cost $0.07 at Rat Shack. In all, I have $4.87 invested in my stir plate, and it does the exact same job as my buddy's $100 model.
 
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