Originally Posted by Mellow52
It sounds like you have the electronics wrong.
I'm fairly positive the electronics are fine. I have the same parts as the OP and my wiring is the same way. I had it wired a different way at first and it didn't work. I re-examined the posts here, found my problem, changed the wiring and it works now.
FWIW, the rheostat does control the speed of the fan. When I turn the dial it speeds up to full force. It's just that even on the lowest setting it's nowhere near "a crawl".
I did look up some fans that others here have used and I'm seeing that many of them have much lower RPMs than mine so it makes sense that those might spin much slower than mine at the low setting.
It's no big deal.... I got the bar to spin this morning in the flask and let it run for 1 1/2 hours while I worked out and it did fine... didn't throw the bar. I really hate the hexagon shape of this particular bar and I think I'll have more success with the smaller, flat, round bar that I've ordered.
Originally Posted by camiller
Are those magnets glued down? I know I originally thought mine would hold itself to the washer by magnetic force alone, but after awhile the magnet started drifting. If your fan isn't slowing down much an additional resistor or lower voltage is in order.
In theory there is a point above which shearing force could cause damage to the yeast ... but your not anywhere close to that.
Edit: you are also the first I've seen to use ring magnets.
Thanks for the post! No, the magnets are not glued down. Those are "super magnets" I picked up at Home Depot and it was VERY difficult for me to pry them apart so I figured they would hold just fine but I'll open it up and see if they've moved at all. Honestly the thing works just fine on the smaller jar it's the flask that I'm having hit or miss success with and I really do think (from all the reading I've done) that the smaller, flat round bar will make a difference. If it doesn't, I'll rip out that 12 v power and put a 9 v on it. I'm not gonna let a little stir plate kick my a**
Here's a picture of it spinning in the flask. I also discovered that if I got the magnet centered.... then lifted the flask just a little while starting the fan until the vortex got going and then set it down I had better chance of it not throwing the bar. This makes me think maybe I should lower the fan inside by 1/8".