Stir plate computer fan problem?

[jgoodhart]

So I have a 12vdc/2amp computer fan that I am trying to power with a 9vdc/1amp wall power adapter. My fan has red, white and black braided wire going into the fan and the wall charger just had a positive and negative. I placed positive to positive and negative to negative and left the white (ground) out. My fan will start up and spin for a second and then quit and repeat that cycle. Am I wiring something wrong or do I need more volts/amps from the wall adapter? Any help appreciated.View attachment ImageUploadedByHome Brew1459178067.510508.jpgView attachment ImageUploadedByHome Brew1459178092.394893.jpg

 

[b-boy]

I'm guessing you're underpowered.

 

[martyjhuebs]

I just created another post and I have the opposite problem. With 9v Volts I have to turn my potentiometer all the way up quick to get it started. Do you have a potentiometer attached?

 

[JONNYROTTEN]

I realize your mostly done with your project but if you run into a wall you could try this.I haven't bought it yet but read others have used it. Practically plug and play for $12.This is the route I'm going to go.

https://www.amazon.com/gp/product/B00080G0BK/?tag=skimlinks_replacement-20

 

[b-boy]

Honestly, for around $30 you can get a used lab-grade stir plate on E-Bay. I got one for $25 that looks to be brand new. It may take awhile, but if you bid on a few, you'll eventually get a good deal. I pick them up whenever I see a good deal. These things are indestructible and made for this application. Plus, you can always resell it for what you paid for it.

I generally look for Corning brand. This is my favorite model: http://www.ebay.com/itm/Corning-PC-...536575?hash=item5b224da03f:g:64EAAOSwJQdW-II4

 

[jgoodhart]

Martyjhueb, I just switched the fan out to a smaller 12v/.25 amp that I am powering with the same 9v/.3amp charger. I have the same problem now. I have to have the potentiometer turned all the way up on start up to get it to start spinning but then I can dial it down...works for now. I might look into the usb version later on. Thanks for the replies.

 

[martyjhuebs]

Martyjhueb, I just switched the fan out to a smaller 12v/.25 amp that I am powering with the same 9v/.3amp charger. I have the same problem now. I have to have the potentiometer turned all the way up on start up to get it to start spinning but then I can dial it down...works for now. I might look into the usb version later on. Thanks for the replies.

I think my issue is that pot is too big... my is basically just a switch to turn it off and on, it won't dial it down...

 

[NeoBrew]

You might benefit from putting a non-magnetic spacer between the magnets and the fan. Some people use a piece of PVC pipe.

I mounted my magnets to an 1/8" thick disc then right onto the fan. The magnets seem to interfere with the magnets in the fan motor. I reach under mine and spin the fan, then it has enough momentum to keep running. It's a real PITA, but I build my enclosure too thin to add a spacer. One of these days I'll mod it.

 

[martyjhuebs]

Just an update... made a trip to RadioShack and got a 25k 3W For about $5 and it works flawlessly