Motor-less stir plate?
- Thread starter MikeYoung
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ajwillys
Well-Known Member
Sounds genius! The first question I would ask is why don't the labs use them? If it is the more practical alternative, I would think they would use them.
kpr121
Well-Known Member
That fan burns less electricity than most home stereos that are plugged in but turned off.
With that being said, it does sound pretty cool. Can you install leds that show which magnets are firing as well? It would look like some sort of spaceship taking off.
With that being said, it does sound pretty cool. Can you install leds that show which magnets are firing as well? It would look like some sort of spaceship taking off.
MikeYoung
Well-Known Member
They would appear to be "on" continuously, at least from a persistence of vision point of view.
Still just tinkering with the idea. Doesn't need to be as complicated as a brushless controller. Just needs cycle through the coils in sequence. I doubt there'll be enough of a feedback current for position sensing, but I won't know until I (or someone
) tries it.
runningweird
Well-Known Member
I always thought a Tesla Turbine would be interesting to turn into a yeast stir plate
Yes, it's been tried. Someone started a thread on this and had a half-assed prototype built, but as is often the case, was never heard from again after a few posts. IIRC, he had wound the magnet coils by hand. I dont' remember what he was using to fire them sequentially. It was an interesting experiment and I'm sure the concept could be made to work, but I seriously doubt that there's much, if anything at all, to be gained over the muffin fan approach.
You might be able to locate the thread using the search feature. It was only a year or so ago that the guy posted. Too bad the project apparently died on the vine.
Aren't many of the computer case fans folks use for stirplates brushless anyway? I suspect you'd have to get something like that really close to the starter vessel - probably wouldn't be generating much of a field, and the diameter is awfully small.
Still, it might be an interesting exercise to disassemble a case fan (remove the fan blade part) and see if you could get a stir bar to spin separated by a piece of glass or plexiglass.
Still, it might be an interesting exercise to disassemble a case fan (remove the fan blade part) and see if you could get a stir bar to spin separated by a piece of glass or plexiglass.
Golddiggie
Well-Known Member
People glue a rare earth magnet onto the fan so that it also spins. Usually the magnet is salvaged from an old 3.5" hard drive.. On top of that, all you need is an enclosure, power supply (easy on both counts) and a way to control the fan speed (also easy to do/find)...
I almost built one, but it was becoming more involved than I wanted to entertain. So I just purchased one that has the speed control already in it.
LordUlrich
Well-Known Member
Sounds like a steeper motor. It sounds feasible but while it might be more efficient (or not). When it comes down to it you are likely to spend more on controls for your stir-plate than the motor. As with may things, a "better" solution loses out when a low cost, working solution exists.
iaefebs
Well-Known Member
I think my Lab disk, VWR made by IKA works that way. The thing is less than a 1/2" thick. I's rated for 800ml but I've used it for 1 liter starters. The description is:
VWR Lab Disc Magnetic Stirrer 115V, 50/60Hz. Speed: 15-1500rpm. Stirring capacity: 800mL of water. Ultra-flat stirrer with advanced magnetic coil technology has no moving parts to wear out. Direction of rotation can be set to reverse every 30 seconds. Polyester plate surface. 11.4Wx16.1Dx1.2Hcm
I use it for small starters or when snatching yeast from a bottle,
I use my StirStarter for anything larger.
thargrav
Well-Known Member
I attempted a design at a motorless stir plate. I designed a controller that would do a rotating field. My issue was that I could not make a set of electromagnets near as strong as a super magnet.
The low cost fan motors we use in our stir plates & everyone else uses in their stir plates is a 4 pole motor and the motor drive is offset internally so it only spins one direction. Even commercial stir plates use a spinning motor. The more expensive ones use a stepper motor.
The low cost fan motors we use in our stir plates & everyone else uses in their stir plates is a 4 pole motor and the motor drive is offset internally so it only spins one direction. Even commercial stir plates use a spinning motor. The more expensive ones use a stepper motor.
thargrav
Well-Known Member
I'l like to take one of these apart - like I said in my last post I could not wind strong enough magnets and I want to see how they did theirs.
I tried building one a while back but never really got it working well. I used a 555 timer with a pot to vary the frequency and fed that into a octal counter (cd4022) and the output of that into mosfet drivers and several H-bridges of course powering electromagnets. the issue was I couldnt make the electromagnets strong enough. I think at high speeds I had issues with eddy currents in the soft iron cores. regular electric motors use laminated silicon steel to reduce eddy currents at high speeds, but that's a little of my reach.
bottom line if you can make or find electromagnets that maintain strength at higher switching speeds you should be able to make a very fancy stirplate.
bottom line if you can make or find electromagnets that maintain strength at higher switching speeds you should be able to make a very fancy stirplate.
iaefebs
Well-Known Member
I've never seen another one come up for sale. I bought it used 5 years ago. The phone number on the back is (910) 452-7059. Maybe you could get some info from them.
MikeYoung
Well-Known Member
Thanks. That all sounds right. The linear drive magnet from a HD is practically free, incredibly strong, and draws no power.
The trouble is, I still need a stir plate, but all the dead power supplies here died of cooling fan failure; no muffin fans on hand. I have a few CD drive motors that I rewound some years ago to power R/C foamie planes (90W+ without overheating). Overkill for this and a waste of a controller, but they're paid for and just gathering dust now. The bonus, though, is I could just plug it into a receiver, saving the trouble of wiring a pulse generator to control it, and control it from my comfy chair.
The trouble is, I still need a stir plate, but all the dead power supplies here died of cooling fan failure; no muffin fans on hand. I have a few CD drive motors that I rewound some years ago to power R/C foamie planes (90W+ without overheating). Overkill for this and a waste of a controller, but they're paid for and just gathering dust now. The bonus, though, is I could just plug it into a receiver, saving the trouble of wiring a pulse generator to control it, and control it from my comfy chair.
thargrav
Well-Known Member
You could just buy a stir plate - several of us are building low cost versions for sale.
Without sidelining this discussion, each of us think our design is the best.
Without sidelining this discussion, each of us think our design is the best.
thargrav
Well-Known Member
I did a chase on-line and it looks like the model didn't survive. I'd think if it were truely better than the rotating magnet model then they would still be acound and would have at least 3 cometitors building something similar by now.
iaefebs
Well-Known Member
I agree. But it is good for what I use it for. Small starters and cultivating yeast from bottles. I like it better than my StirStarter in those applications. But it won't stir a 2 liter + batch. What's a chase on-line? is that a Google for Androids? I google chase on-line and get a bank.
MikeYoung
Well-Known Member
I'm still lmao reading some of the older threads. Had no idea it was such a cutthroat market.
I wonder if you can understand what I'm going through. These things are, like, OMG it's 1980 again and I'm reading the IC Cookbook with LM317 and 555 timer hacks. And I somehow can't get myself to drive to Radio Shack to see if they have a muffin fan hanging on their wall.
Couldn't I just pump air into the starter with the aquarium pump and approximate all this stirring?
thargrav
Well-Known Member
I'm still lmao reading some of the older threads. Had no idea it was such a cutthroat market.
I wonder if you can understand what I'm going through. These things are, like, OMG it's 1980 again and I'm reading the IC Cookbook with LM317 and 555 timer hacks. And I somehow can't get myself to drive to Radio Shack to see if they have a muffin fan hanging on their wall.
Couldn't I just pump air into the starter with the aquarium pump and approximate all this stirring?
Once yeast settles out it gets covered by more yeast bodies that settle out and the lower layers lose contact with the wort and stop growing. The end result is - only what's left in suspension and the top layers of what's in the flask grows new yeast. A stir plate keeps all of the yeast in suspension and grows a starter much faster than even the starters that are swirled twice a day. Air would work if you could agitate the entire flask with air and inject absolutely clean air.
And you are correct, it is a very cut throught market and there is a lot of mis-information out there. It seems a lot of people are willing to "bend the truth" just to make a dollar. But this is not true for just stir plates.
BTW, I'm about to launch a stir plate that will easily stir a 5 gallon batch. I have a batch on my prototype now and it's happily stirring away. This stir plate is not for starters even though you could do a starter on one. It's for high gravity brews that tend to stall before they finish.
I attached a picture of the prototype.
ajwillys
Well-Known Member
How much? Very interested. I can imagine many microbreweries that might be interested in this. For those guys, 5 gallons is a starter
thargrav
Well-Known Member
How much? Very interested. I can imagine many microbreweries that might be interested in this. For those guys, 5 gallons is a starter
I'm looking at $159.95 retail. The stir plate will come with two 2" long stir bars and has a much stronger motor & stronger magnets than the other two models we build. The magnets are so strong that if I accidently put two together I can't separate them.
The other two we build are priced $129.95 (Stir Plate 3000) & $89.95 (Stir Plate 2000) and if you are curious about what they look like you can see them at our www.towercooler.com web site. FOXX Equipment sells the other two models we build and you can find them at many homebrew shops. I hope they also decide to sell our new model.
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