Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Suitable motor to run a large diy mag stirrer.
nannah
Hazard to Others
***




Posts: 136
Registered: 20-12-2013
Member Is Offline

Mood: No Mood

[*] posted on 20-12-2013 at 14:06
Suitable motor to run a large diy mag stirrer.


Hey, guys! I have some questions that i hope you could help me out with.
The thing is, i am in the market to buy a new stirrer-hot plate, or heating mantle, and got the idea when i yesterday was qruising on ebay, checking out some heating mantles, that it would be cool if i could make my old rice cooker to a mag stirrer, (and maybe even heater).

I started investigating, and took it apart today. I don´t think it is impossible to see this through. I wish i could post some pictures, but i don´t have a camera to take pics. You have to visulize.

Here is one that looks very similar to the one i got.
http://www.ebay.co.uk/itm/BREVILLE-ITP135-RICE-COOKER-AND-ST...

My cooker fits 10 liters, and i would like it to be able to stir at least 5 liters minimum. It´s always better to have more then you need, in case i would need it some day.
I think i probably need to get a little bit more powerful motor then a PC fan like i have seen ppl mostly use for their diy stirrers.
Maybe a small inline fan motor, or something like that?

I will try to explain this the best way i can. I hope you are firmiliar with rice cookers, otherwise you might not understand what i mean half the time. Feel free to ask if i am unclear on something.

Ok, so i started with unscrewing the screws on the underside that held it together. Then i unscrewed the wires, and the screws that the "heater" were fasten with and took out the heater-part and reassembled it again.

Do anyone have any feedback to give me? It would be greatly appreciated. :)

View user's profile View All Posts By User
eesakiwi
Harmless
*




Posts: 27
Registered: 10-8-2005
Member Is Offline

Mood: drawnout

[*] posted on 20-12-2013 at 16:10







This may help. Its as far as I got to making one.
I'm thinking a microwave magnet would be best, or a super hight temp magnet. The ones out of a hard drive are strong, but loose their strength quickly when heated.

[Edited on 21-12-2013 by eesakiwi]

[Edited on 21-12-2013 by eesakiwi]

[Edited on 21-12-2013 by eesakiwi]
View user's profile View All Posts By User
confused
Hazard to Others
***




Posts: 244
Registered: 17-3-2013
Location: Singapore
Member Is Offline

Mood: tired

[*] posted on 20-12-2013 at 17:06


what type of high temperature magnets are you considering, the only ones i can find are Samarium Cobalt Magnets and they seem quite pricy and can only handle temperates up to 550'c

also, what microwave magnets are you refering to?
not sure if the magnets from a magnetron would work as it's only the food itself that heats up due to the microwaves and not the magnetrn itself, i could be wrong though

http://en.wikipedia.org/wiki/Curie_temperature
View user's profile View All Posts By User
nannah
Hazard to Others
***




Posts: 136
Registered: 20-12-2013
Member Is Offline

Mood: No Mood

[*] posted on 21-12-2013 at 01:11


Hey, thanx for the replies. Cool that somebody else has thought of this too. You didn´t finish it if i understood it right, btw?

I don´t know what kind of magnets i am going to use. I actually did hope that you guys knew about that.

I have found these Neodym magnets that i have thought about.

But anyway, if i get all of this running, and would want to make it into a heater as well. Would any of you see any solutions to that?

I was thinking that maybe i could heat oil/water in the bowl with nichrome wire. What about that?

Btw, i meant the bowl holds 10 cups, not liters.

[Edited on 21-12-2013 by nannah]
View user's profile View All Posts By User
unionised
International Hazard
*****




Posts: 4292
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 21-12-2013 at 06:17


"I have found these Neodym magnets that i have thought about. "
I think you might need to think again.
http://en.wikipedia.org/wiki/Neodymium_magnet#Magnetic_prope...
http://en.wikipedia.org/wiki/Curie_temperature
View user's profile View All Posts By User
cpman
Harmless
*




Posts: 36
Registered: 9-12-2013
Location: Austin, TX
Member Is Offline

Mood: No Mood

[*] posted on 21-12-2013 at 09:11


An electromagnet would probably work best if you are doing a heated stirrer. They don't lose strength in high temperatures. Also, it would be much cheaper than buying samarium-cobalt or other high temperature/high strength magnents.
View user's profile View All Posts By User
DubaiAmateurRocketry
International Hazard
*****




Posts: 843
Registered: 10-5-2013
Location: LA, CA, USA
Member Is Offline

Mood: In research

[*] posted on 21-12-2013 at 16:26


Quote: Originally posted by nannah  

I have found these Neodym magnets that i have thought about.


that will crush your glass ware, and break ur fingers.
View user's profile View All Posts By User
nannah
Hazard to Others
***




Posts: 136
Registered: 20-12-2013
Member Is Offline

Mood: No Mood

[*] posted on 22-12-2013 at 04:26


Quote: Originally posted by DubaiAmateurRocketry  
Quote: Originally posted by nannah  

I have found these Neodym magnets that i have thought about.


that will crush your glass ware, and break ur fingers.


Really, are they so strong? Thats crazy. I will take a look where i can get a hold of some electromagnets then. :)

My plan was first and foremost to make it into a stirrer, but if it was possible i thought that if would be great if i could use the bowl to contain oil or water thats heated with nichrome wire.
My first thought was to use the bowl to hold ice-baths, and maybe that isn´t a bad idea.


I bought a hotplate thats a 60Hz, so it doesn´t work over here in europe because the frequency difference.
I have thought about if maybe it is possible to take parts from it, and use them in another?
Or, what do you guys think one have to do in order to get a 60Hz hotplate to work over here where we ?
Do i need some hi-tech frequency transformer, re-wire it? Or would just a us --> europe travel adapter work? Can it be that simple?

thanx in advance, and thnx for the replies. :)

[Edited on 22-12-2013 by nannah]

[Edited on 22-12-2013 by nannah]
View user's profile View All Posts By User
unionised
International Hazard
*****




Posts: 4292
Registered: 1-11-2003
Location: UK
Member Is Offline

Mood: No Mood

[*] posted on 22-12-2013 at 08:21


Feeding power to an electromagnet would be a problem. It's possible, but a lot of work.
"I bought a hotplate thats a 60Hz, so it doesn´t work over here in europe because the frequency difference. " The frequency isn't likely to be the big problem. What's the voltage?
View user's profile View All Posts By User
nannah
Hazard to Others
***




Posts: 136
Registered: 20-12-2013
Member Is Offline

Mood: No Mood

[*] posted on 24-12-2013 at 05:12


Quote: Originally posted by unionised  
Feeding power to an electromagnet would be a problem. It's possible, but a lot of work.
"I bought a hotplate thats a 60Hz, so it doesn´t work over here in europe because the frequency difference. " The frequency isn't likely to be the big problem. What's the voltage?


Its a 120V. Can i in some way convert it into a 220V?

I am going to google it right now, but if you have any thoughts i would be very interested in hearing them.

Thanc btw. :)
View user's profile View All Posts By User
nannah
Hazard to Others
***




Posts: 136
Registered: 20-12-2013
Member Is Offline

Mood: No Mood

[*] posted on 25-12-2013 at 04:44


If i would to build a diy magnetic stirrer, like this one here:

http://www.instructables.com/id/How-to-Make-a-Cheap-Portable...

Do you think that i will need a little bit more powerful fan a ordinary pc fan?
When i check these diy projects ppl post pictures of, it looks like they are stirring pretty decent actually.

I was thinking that i would get some Glas Col mantles and just place them on top of the stirrer.

One thing that i worry about thou, is sparks. What can you do about that?
View user's profile View All Posts By User
joms
Harmless
*




Posts: 1
Registered: 1-1-2014
Member Is Offline

Mood: No Mood

[*] posted on 1-1-2014 at 04:49


I found SmCo-magnets cheap on ebay, works just fine in my diy rice-cooker heater/stirrer.
I never run above 250C though.
View user's profile View All Posts By User
hydride_shift
Harmless
*




Posts: 23
Registered: 25-7-2013
Member Is Offline

Mood: sp3 hybridised

[*] posted on 28-2-2014 at 06:36


Was trying to find the best place to post this but here goes

I recently found this using a PC fan with a PWM to control the speed
http://www.instructables.com/id/Variable-speed-magnetic-stir...

With a bit of trial and error i got this



Heres a video showing it in action and discussing its construction
http://www.youtube.com/watch?v=K8S9IoeWNJ4
View user's profile View All Posts By User
Panache
International Hazard
*****




Posts: 1131
Registered: 18-10-2007
Member Is Offline

Mood: Green is not a creative colour

[*] posted on 7-3-2014 at 16:13


Sounds silly but disco ball motors have appropriate torque and speed for mag stirrers, just buy good ones designed for clubs/continuos long term use, not the ones from aldi or some hobbyists electronics store. Decent rare earth magnet attached, then it's simply a matter of establishing the optimum height above the spinning field where your stirrer bar is compelled to slavish tendencies.



View user's profile View All Posts By User
Organikum
resurrected
*****




Posts: 2228
Registered: 12-10-2002
Location: Europe
Member Is Offline

Mood: fluffy!

[*] posted on 7-3-2014 at 17:30


IKA and other professional brands use split pole motors, those are found for free in old microwaves for the fans.
The split pole motor is rather easily regulated in speed and its sparkless. Most important are the somewhat odd torque caracteristics of this kind of motor which makes the motor not so easily "overrun" the stirring magnet but to adapt quite elastic to the task.

Magnetic stirrers may be sold with a 20 liter label - thats for pure water at 18°C only of course. For everything whats not a plain liquid with low viscosity and over 1 liter one uses an overhead stirrer.
It makes really a big, big difference.

5 liter as named in the beginning with a magnetic stirrer? There should be a very good reason to do so and one can expect substandard results compared to stirring overhead with a blade suited for the task.
I cannot imagine what it could be.
Hm.

/ORG




Restrict alcohol and Tobacco.
Legalize everything else.
Mandatory LSD for politicians and Franklyn.
View user's profile View All Posts By User

  Go To Top