Hey guys,
I'm looking to put together a stir plate, and i'm getting kind of confused about how I should control the speed of the fan. Some people recommend buying a fan with build in speed control, but these don't seem to be widely available. So I guess I'm looking at a potentiometer/rheostat set up? Has anyone built one of these recently that might point me in the right direction?
Large 12v fan and one of these http://www.amazon.co.uk/gp/aw/d/B0083S19YW/ref=mp_s_a_1_3?qid=1454330407&sr=8-3&pi=SY200_QL40&keywords=variable+power+supply&dpPl=1&dpID=41s1vfDHclL&ref=plSrch
Steel adhesive strip for top of fan and allow you adjust magnet position and some powerful magnets and that's it
Quote from: CH on February 01, 2016, 12:41:06 PM
Large 12v fan and one of these http://www.amazon.co.uk/gp/aw/d/B0083S19YW/ref=mp_s_a_1_3?qid=1454330407&sr=8-3&pi=SY200_QL40&keywords=variable+power+supply&dpPl=1&dpID=41s1vfDHclL&ref=plSrch
Steel adhesive strip for top of fan and allow you adjust magnet position and some powerful magnets and that's it
Looks good, thanks! I assume you rip the end of the adapter off, and solder positive and negative connections into the fan?
Or you just hook up the fan to one of these in a project box
http://www.maplin.co.uk/p/21-x-55mm-dc-socket-plastic-ft96e
That way you can keep the power adapter intact
These guys at top of pic on eBay either if you don't want to cut wires on transformer(http://uploads.tapatalk-cdn.com/20160201/468020611dd4b2b8552cade5bcb97cd2.jpg)
i got one of these for controlling the speed
http://www.ebay.com/itm/12V-40V-10A-Pulse-Width-Modulation-PWM-DC-Motor-Speed-Control-Switch-13KHz-DX-/271803656301
Would that not fry a 12v fan?
I bought a USB fan and added some magnets ripped from an old hard drive
its fine for me, its rated for 12v - 40v but depending on the plugyou use you will only be supplying 12v max (actually have mine at 9v)
Sound
Wow costs of these thing has tanked here's one with a seperate switch and speed controller!!
(http://uploads.tapatalk-cdn.com/20160201/31a0edf1db1b1c85d455206ca116a909.jpg)
Quote from: craiclad on February 01, 2016, 11:50:47 AM
Hey guys,
I'm looking to put together a stir plate, and i'm getting kind of confused about how I should control the speed of the fan. Some people recommend buying a fan with build in speed control, but these don't seem to be widely available. So I guess I'm looking at a potentiometer/rheostat set up? Has anyone built one of these recently that might point me in the right direction?
I know a project is a great thing but if you're on the fence at all I cannot recommend the following stirplate enough:
http://www.digitalhomebrew.com/digital-stirplate-v3
I think molc found it originally and honestly it's unbelievable.
Quote from: Vermelho on February 01, 2016, 09:04:29 PM
Quote from: craiclad on February 01, 2016, 11:50:47 AM
Hey guys,
I'm looking to put together a stir plate, and i'm getting kind of confused about how I should control the speed of the fan. Some people recommend buying a fan with build in speed control, but these don't seem to be widely available. So I guess I'm looking at a potentiometer/rheostat set up? Has anyone built one of these recently that might point me in the right direction?
I know a project is a great thing but if you're on the fence at all I cannot recommend the following stirplate enough:
http://www.digitalhomebrew.com/digital-stirplate-v3
I think molc found it originally and honestly it's unbelievable.
This. Get it and never think about your stir plate again. Sometimes it's just worth paying the money for the lack of hassle.
Think it was Jacob that put me into it originally.
Quote from: CH on February 01, 2016, 06:43:44 PM
Wow costs of these thing has tanked here's one with a seperate switch and speed controller!!
(http://uploads.tapatalk-cdn.com/20160201/31a0edf1db1b1c85d455206ca116a909.jpg)
Looks perfect for the job,all you would need is a project box large enough to accept an old PC fan underneath top plate and you are sorted. ;D
I just completed my stir plate build and I'm very happy with how it went. Still waiting on my erlenmeyer flask before I can put it to proper use though.
Video here: https://www.youtube.com/watch?v=iR9pjS6nQMQ
Parts list:
- Project Box (http://www.ebay.ie/itm/172086885941?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €4.30
- 12v DC fan (http://www.ebay.ie/itm/321946147943?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €1.70
- PWM with digital display (http://www.ebay.ie/itm/381147045732?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €6.35
- Rare earth magnets (http://www.ebay.ie/itm/351416155240?_trksid=p2057872.m2749.l2649&var=620505753355&ssPageName=STRK%3AMEBIDX%3AIT) - €3
- Nuts & bolts for mounting - €3
- 19v laptop charger (!!!) - salvaged
Less than €20 on parts but did spend around another €10 for shipping. It'd be possible to get a cheaper PWM and salvage a hard drive magnet if you really wanted to do this on the cheap but I'm happy with what I've spent.
Only snag I ran into was using a mobile phone charger to power it. I had it all wired up, assuming the charger was 12v. However, only after hot gluing it in place and firing it up, I realised it was only 5v and barely got the smallest bar to move. So, since my PWM was rated for 24v, I thought why not use my 19v laptop charger and just reduce the speed so as not to burn out my fan. The digital display comes in really handy for controlling the speed accurately and I think I'll appreciate the extra length of the laptop cord when leaving it somewhere to stir.
Just a note on the video. I'm using the medium sized bar and it doesn't spin until I crank it up to ~35, but the small bar spins fine at lower speeds. The big bar spins nicely too, even at high speeds.
Fire away with any questions, happy to help if I can.
Looking good, do a test with an erlenmeyer or demijohn.
You only need to keep the yeast in suspension not make whipped cream.
I really like the digital display
Not much difference in price between that PWM and similar ones with no display so thought sure why not!
I have a 5L Erlenmeyer on the way so can't wait to see how that fares. I have the ingredients for a Rochefort 8 clone here waiting but I can't put it on until I can make a big starter. It's making the anticipation much worse.
I have most of my parts which are
Plastic Box with clip seals - Dealz €1.50 for 2
Fan - Off old computer - Free
Magnet - Off old hard drive - Free
And using one of these plugs, found in most poundshops or more than likely you have one in some draw in the house, cut of the ends and connect the 2 wires to fan wires, use the power switch between 3v-12v to increase/decrease speed of fan
(http://i.ebayimg.com/images/i/261803599385-0-1/s-l1000.jpg)
Thats what I have and its great
Quote from: gazz on February 25, 2016, 04:16:28 PM
I have most of my parts which are
Plastic Box with clip seals - Dealz €1.50 for 2
Fan - Off old computer - Free
Magnet - Off old hard drive - Free
And using one of these plugs, found in most poundshops or more than likely you have one in some draw in the house, cut of the ends and connect the 2 wires to fan wires, use the power switch between 3v-12v to increase/decrease speed of fan
Can you get that type plug in pundshop here? I've never seen one here.
Maybe they are not as popular now with everything using the standard USB chargers, but look about in the cheap shops for em, you could use any old charger Nokia etc but it would be at the one speed. Somebody you know has one of these in the old draw with all the spare bits and bobs that's in every house
I used an old Nokia charger and it turned out to be only 5V. Make sure it's 12V before using it, otherwise it won't spin.
Quote from: BrewDorg on February 24, 2016, 08:34:48 PM
I just completed my stir plate build and I'm very happy with how it went. Still waiting on my erlenmeyer flask before I can put it to proper use though.
Video here: https://www.youtube.com/watch?v=iR9pjS6nQMQ
Parts list:
- Project Box (http://www.ebay.ie/itm/172086885941?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €4.30
- 12v DC fan (http://www.ebay.ie/itm/321946147943?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €1.70
- PWM with digital display (http://www.ebay.ie/itm/381147045732?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) - €6.35
- Rare earth magnets (http://www.ebay.ie/itm/351416155240?_trksid=p2057872.m2749.l2649&var=620505753355&ssPageName=STRK%3AMEBIDX%3AIT) - €3
- Nuts & bolts for mounting - €3
- 19v laptop charger (!!!) - salvaged
Less than €20 on parts but did spend around another €10 for shipping. It'd be possible to get a cheaper PWM and salvage a hard drive magnet if you really wanted to do this on the cheap but I'm happy with what I've spent.
Only snag I ran into was using a mobile phone charger to power it. I had it all wired up, assuming the charger was 12v. However, only after hot gluing it in place and firing it up, I realised it was only 5v and barely got the smallest bar to move. So, since my PWM was rated for 24v, I thought why not use my 19v laptop charger and just reduce the speed so as not to burn out my fan. The digital display comes in really handy for controlling the speed accurately and I think I'll appreciate the extra length of the laptop cord when leaving it somewhere to stir.
Just a note on the video. I'm using the medium sized bar and it doesn't spin until I crank it up to ~35, but the small bar spins fine at lower speeds. The big bar spins nicely too, even at high speeds.
Fire away with any questions, happy to help if I can.
Let me begin by blaming you.....id stopped making stuff but now I want to make a stir plate...it's all your fault cause this is going to lead to trouble lol😂😂😜😜
Just one question about magnets, what size did you get in the end? 8x2mm? Or bigger smaller
Cheers
@Brewdorg, can post a pic of your motor/Magnet assembly?
Its the bit that I have found tricky as it needs to be balanced to reduce vibration.
No hassle lads, I'll crack open my stir plate after work and take pics.
@ Oh Crap, I'll happily take the blame for that! I got the 8 x 2 mm magnets and stacked 2 on top of each other.
@ John I just remembered how I got such good placement on the magnets. I had an old hard drive magnet that I glued to the center of the fan first. Then I simply positioned my stacked 8x2mm magnets at either side of that magnet until it spun nicely. They're more than strong enough to stay in position too so I didn't hot glue them. I'll take pics later anyway!
Something I noticed when attempting to build one of these was the magnets on the fan affected the magnetic field on the fan motor.
The lag you experience at low rpm may be directly related to this.
Quote from: johnrm on March 11, 2016, 11:44:16 AM
Something I noticed when attempting to build one of these was the magnets on the fan affected the magnetic field on the fan motor.
The lag you experience at low rpm may be directly related to this.
It more than likely is. The magnets actually stick to the metal through the plastic fan blades. My 19v charger does more than enough to compensate though!
Lot's of DIY stir plates builds have a metal washer glued to the fan and then the magnets stuck to the washer. That would probably prevent the lag due to magnetism too. Although the added weight of the washer would probably mean any gains are negligible!
Great job BTW!
I use a self adhesive metal strip and attach it to the fan then you can adjust the magnets to where you want them
Quote from: CH on March 11, 2016, 09:35:44 PM
I use a self adhesive metal strip and attach it to the fan then you can adjust the magnets to where you want them
Where would I get self adhesive metal strips at all?
Totally forgot to post these pictures.
Just on using the 19v charger with the 12v fan, how do you stop it from burning out? Have you a resistor or something else that stops more than 12v going into the fan?
The potentiometer is used to limit the voltage. I turn it up just enough to spin the bar, roughly 55-60 on the digital display.
I recently found a 5V laptop fan and a 5V power supply. I take it these will not be strong enough for a decent stirplate ? ;D
Quote from: Greg2013 on March 27, 2016, 11:05:31 PM
I recently found a 5V laptop fan and a 5V power supply. I take it these will not be strong enough for a decent stirplate ? ;D
Nah 5v won't work. I had the 5v in first and it wouldn't even spin. 12v is pretty much perfect but most old chargers aren't 12v, just 5v.
Btw where'd you get the bolts and washers to attach the fan? Do you need to give it much clearance under the lid?
Quote from: BrewDorg on March 27, 2016, 11:31:24 PM
Quote from: Greg2013 on March 27, 2016, 11:05:31 PM
I recently found a 5V laptop fan and a 5V power supply. I take it these will not be strong enough for a decent stirplate ? ;D
Nah 5v won't work. I had the 5v in first and it wouldn't even spin. 12v is pretty much perfect but most old chargers aren't 12v, just 5v.
I will have to go scrounging again so. I wish i could just buy a parts kit off internet but no luck so far. ;D
You can...
http://digitalhomebrew.com/
Aliexpress
Mini Magnetic, Magnetic Stir Plate Not Heating with Holder Magnetism Mixer for Laboratory.Magnet Mixer
http://s.aliexpress.com/MR3iauEZ
(from AliExpress Android)
Quote from: cruiscinlan on March 27, 2016, 11:57:53 PM
Btw where'd you get the bolts and washers to attach the fan? Do you need to give it much clearance under the lid?
Bought them in woodies. M4 x 20mm as far as I remember. I gave them 1 M4 bolt of clearance which is plenty. The fan sits so tightly onto the screws that I didn't even need to bolt it tight, it's nicely wedged already.