Happy HolidaySs Giveaway - Winners Re-Re-Drawn - 24 hours to Claim!

Get your HBT Growlers, Shirts and Membership before the Rush!


Home Brew Forums > Home Brewing Beer > DIY Projects > Chillers and Stir Plates > Stir plate Help
Reply
 
LinkBack Thread Tools
Old 12-25-2012, 11:48 PM   #1
Oldpesos
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 6
Likes Given: 1

Default Stir plate Help

Hello all, and Thank you in advance for your input, Now I know one does not need a large Vortex but I want to be able to achieve one and have been unable too, I am using a 120mm 12 Volt 0.36 amp fan and a 12 volt 1 amp power supply hooked directly too the fan. I am using a 2" magnetic stirbar and Four (4) 1/2" x 1/16" rare earth magnets double stacked in a row two sets North two sets South. No problem turning the bar But I hardly make a dimple in my 2000 ML Flask weather its filled half way or Full to the 2000 ML line. Id like to be able to create a larger vortex, Do I need Larger more powerful magnets or a fan with higher amperage etc. Awaiting your Kind replys. Thanks again.

__________________
Oldpesos is offline
 
Reply With Quote Quick reply to this message
Old 12-26-2012, 12:04 AM   #2
castermmt
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
castermmt's Avatar
Recipes 
 
Join Date: Dec 2010
Location: Lowell, Indiana
Posts: 206
Liked 10 Times on 7 Posts
Likes Given: 23

Default

it should work based on your set up. Make sure the fan is spinning and your getting the proper voltage to the fan. You may need to look at the speed control and make sure you have it set up properly as well. You can check it measuring the output voltage from the control to the fan. Marry Christmas And Happy New Year, Castermmt

__________________

Fuzzy Logic Brewery, Check it out here http://www.homebrewtalk.com/f170/fuz...rewery-288498/

castermmt is offline
 
Reply With Quote Quick reply to this message
Old 12-26-2012, 12:29 AM   #3
Oldpesos
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 6
Likes Given: 1

Default

Í will check the voltage as I am not using any speed control device.

__________________
Oldpesos is offline
 
Reply With Quote Quick reply to this message
Old 12-26-2012, 12:55 AM   #4
estricklin
Certified Guitar Pickin' Hop Slingin' Crazy Homebrewer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
estricklin's Avatar
Recipes 
 
Join Date: Apr 2012
Location: Oppelo, Arkansas
Posts: 1,212
Liked 149 Times on 120 Posts
Likes Given: 139

Default

The 120mm fans spin MUCH slower than the 80mm that most people use for making stir plates. If you decide to add speed control go with a 100 ohm potientometer, a lot of folks are using 25s and 50s but its my opinion with a 12 v power supply you may need the 100 ohm.

__________________
estricklin is offline
Big_Cat Likes This 
Reply With Quote Quick reply to this message
Old 12-26-2012, 01:32 PM   #5
Oldpesos
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 6
Likes Given: 1

Default

Wow, I went with 120mm Fan because of the Higher amperage , thought it would be better to spin the magnets, never thought they would have less RPM's, makes sense, as far as the potientometer for speed control I will look into your sugestion, although as far as my memory serves me Ohms should compare to the draw of Amperage not the voltage. I know a lot of folks go wrong with potientometer's by picking up 25K ohm or 50K ohm, which is a whole different animal then 25 ohm and 50 ohm. I thank you for your response and will experiment with it.

__________________
Oldpesos is offline
 
Reply With Quote Quick reply to this message
Old 12-26-2012, 10:12 PM   #6
estricklin
Certified Guitar Pickin' Hop Slingin' Crazy Homebrewer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
estricklin's Avatar
Recipes 
 
Join Date: Apr 2012
Location: Oppelo, Arkansas
Posts: 1,212
Liked 149 Times on 120 Posts
Likes Given: 139

Default

A .36 amp 120mm fan is probably spinning in the 2000-2500 RPM neighborhood, which I would think would be enough but who knows.

Let's say you buy this fan or a simular one:
http://www.newegg.com/Product/Produc...82E16835119136

It draws .6 amps.

First let's find the resistance of the fan by using ohm's law R = V/I
12/.6 = 20 ohms.

Now let's assume you went with the 100 ohm potentiometer like this one:
http://www.amazon.com/100-Linear-Tap...+potentiometer

Now we can find the total resistance of the circuit with the potentiometer maxed out.
Total Resistnace = R1 + R2
In our case
100 ohms + 20 ohms = 120 ohms
So the total current for the circuit would be figured
I = V/R
12/120 = .1 amps
Now we can find the voltage drop across the 2, we need to make sure we can turn the voltage way down if you needed to in order to manage the speed of the fan. Using's Ohm's Law again.
V=IR
. 1 x 100 = 10 volts
.1 x 20 = 2 volts
I think 2 volts is plenty low enough.

A lot of guys use 6 volt power supply with a 25 ohm resistor.
Using the same fan
6/.6 = 10 ohms
25 ohms + 10 ohms = 35 ohms (our total resistance)
Total current
6/35 = .171 amps
Voltage Across the reistors
.171 x 25 ohms = 4.29 volts
.171 x 10 ohms = 1.71 volts (at the fan)

Actually now that I think about it here is a high speed 120mm fan that uses 4.8 amps:
http://www.newegg.com/Product/Produc...82E16835706015

You'd still be able to get the voltage down to .3 volts with it.

Hopefully I did all that correctly, if I didn't maybe one of the egineers could please correct me.

__________________
estricklin is offline
Oldpesos Likes This 
Reply With Quote Quick reply to this message
Old 12-26-2012, 10:50 PM   #7
Oldpesos
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 6
Likes Given: 1

Default

Now thats what I call a Response, Thank you, You brought back fond memories of my late Father who was an Electrical egineer, I wish I had him to still go to, Many years ago I would have dreaded his response to such a question which would have been very similar to yours, Now I more then appreciate it. Thank you so much.

Upon checking the voltage today I get 11.79 volts with the meter, so power (voltage ) is there, The MFG. spec's on the fan state approx. 2000 RPM's so I will assume since I am running the fan direct to power sorce that it may not produce enough RPM's to create the Vortex I am looking to achieve so I will purchase another fan.

Thank you again.

__________________
Oldpesos is offline
 
Reply With Quote Quick reply to this message
Old 12-26-2012, 11:39 PM   #8
Zamial
Feedback Score: 0 reviews
Recipes 
 
Join Date: Apr 2010
Location: WI
Posts: 3,184
Liked 168 Times on 149 Posts
Likes Given: 7

Default

Quote:
Originally Posted by estricklin View Post
The 120mm fans spin MUCH slower than the 80mm that most people use for making stir plates.
Some fans get slower w/ the magnets glued on as well. I have a similar setup and I can barley pull the vortex to the bottom of my 2L e-flask. Lucky me, I just got a 5L e-flask for x-mas so I need to rebuild mine...
__________________
“I'm not drunk, I'm from Wisconsin.”
We have been out drinking your state since 1848!
Zamial is offline
 
Reply With Quote Quick reply to this message
Old 12-30-2012, 12:40 AM   #9
Oldpesos
Feedback Score: 0 reviews
Recipes 
 
Join Date: Dec 2012
Posts: 6
Likes Given: 1

Default

Udate, I have purchased a fan with higher RPM's now waiting delivery, however I switched out the fan for an Identical one I had, I now get a vortex 3/4 the way down my 2000 ML Flask, still want a little more but it is acceptable, cant waite to see what the new fan I ordered will do.

To Zamial, whish i had a 5L Flask but I had to settle for a Gallon Wide mouth Glass Jar,

__________________
Oldpesos is offline
 
Reply With Quote Quick reply to this message
Old 12-30-2012, 05:00 AM   #10
estricklin
Certified Guitar Pickin' Hop Slingin' Crazy Homebrewer
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
estricklin's Avatar
Recipes 
 
Join Date: Apr 2012
Location: Oppelo, Arkansas
Posts: 1,212
Liked 149 Times on 120 Posts
Likes Given: 139

Default

Good deal!

__________________
estricklin is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Dramatically improve your Stir Starter stir plate wildwest450 Chillers and Stir Plates 27 03-24-2012 01:05 AM
first time stir plate user, how aggressive should i stir? wncbrewer Fermentation & Yeast 3 01-14-2012 02:35 AM
Stir plate effectiveness concern-maybe too small of a stir bar? crlova2 Fermentation & Yeast 20 03-15-2011 07:06 PM
DIY Stir Plate, Stir Bar attracted to mounts littlejon326 Chillers and Stir Plates 5 03-13-2011 03:12 PM
Stir Plate w/ Stir Rod in Boil Kettle resslerk Chillers and Stir Plates 6 03-20-2010 08:10 PM



Newest Threads

LATEST SPONSOR DEALS