Magnetic stirrer / hot plate from scratch.

[roltex_rohit123]

instead of glass you could use ceramic beaker and it will do all your work. glass i have never used at higher temperatures than boiling acids. and what liquid withstands 500 degrees celcius? are you trying to melt metals? i asked you to giveme details of your project. if you tell me what exactly you want to heat at this temperature, then i could give you many options. you cannot use any glass for heating. you need borosilicate glass for best performance. i can give you designs upto 3000 degree celcius but if you need!! as conserned to magnets they become weak when repeatedly heated at high temperatures.

 

[Sceadwian]

I think this thread is getting out of hand, what is this even for? You're talking about enough heat to cause steel to boil. You're never gonna get that out of a hot plate. We're not even in the realm of rationality anymore.

 

[roltex_rohit123]

i suggested him induction heat instead of heating element!!

 

[adamalden]

3000C elecrical hot plate.

instead of glass you could use ceramic beaker and it will do all your work. glass i have never used at higher temperatures than boiling acids. and what liquid withstands 500 degrees celcius? are you trying to melt metals? i asked you to giveme details of your project. if you tell me what exactly you want to heat at this temperature, then i could give you many options. you cannot use any glass for heating. you need borosilicate glass for best performance. i can give you designs upto 3000 degree celcius but if you need!! as conserned to magnets they become weak when repeatedly heated at high temperatures.

I see... Great post! I am interested in your designs. I have no project other than making this hot plate stirrer. I do not know of a liquid that could withstand this temperature but I know that if you hooked up a reflux condenser to the flask that liquid would drip back down into the flask! =D 3000 C would be awesome! I bet if designed right I could apply an attachment to make it into a small kiln for glass blowing! I have tried to imagine a way to use oxygen and propane or some other gas together to reach these temperatures but I am interested in your "designs" since no electrically resistant wire that I know of can withstand such temperatures.

To go back to the original post which is the most important objective of this thread is the 550C 2000rpm stirrer hot plate. This is an achievable objective. It has been days and I have not received a single bit of technical information. Lets start with this simple question....

If I had electricity and I wanted to put it into a nichrome wire coil to produce heat how could I control the amount of electrical energy precisely and accurately so that there is no dramatic jump in temperature.

An example of what I don't care about is the knob on a simple 15 dollar fan which has 3 speeds. This device must have hundreds of speeds (550 to be exact) so that the temperature could be increased in increments of degrees.

 

[adamalden]

have you ever seen a magnetic stirrer? its not magnet attached to the shaft!!! i am using these in my labs from 5 years. i said that the working is like a brushless motor.. i have also repaired a few which go bad due toguys like you not taking care of it while handling.

For some reason I question why anyone in their right mind would let you work in a lab...

 

[adamalden]

I think this thread is getting out of hand, what is this even for? You're talking about enough heat to cause steel to boil. You're never gonna get that out of a hot plate. We're not even in the realm of rationality anymore.

Hey buddy calm down here. This is my thread not the dna guys... He's the one talking about a 3000C hot plate, glassware exploding at 550C, danger Will Robinson danger... All I want to know is how to make a 550C hot plate with precise temperature control down to increments of degrees. using a knob.

From now on I ask you guys not to talk about anything other than my problem. DONT ask what I want it for since I have already told you. The likeliness of maxing out the temperature and stirring speed on any hot plate is unlikely so why would I do so on mine.

The main problems I am facing with this project is the electrical power going into the magnetic stirring motor and the nichrome wire! What device is used to precisely control the electricity

 

[adamalden]

Umm... Why?!

Because it's cool...

 

[Sceadwian]

You're not going to get precise increments of a degree, not without a remote temperature probe. You could design the heating element to run off mains power and then just use a couple back to back SCRs to control the number of cycles of power the element is getting

 

[adamalden]

You're not going to get precise increments of a degree, not without a remote temperature probe. You could design the heating element to run off mains power and then just use a couple back to back SCRs to control the number of cycles of power the element is getting

Can you explain what these devices do and how they work? Some links would be nice too. The more information the better since I am so inexperienced with electricity.

*can you go into detail on the two subjects bellow?____
-Remote temperature probe.
-SCRs (to control the number of cycles of power the element is getting).

also just to clarify one thing. I understand that I may sound like I want something that is stupidly perfect and will not compromise but this is not the case. I want 550 speeds of heating means I want a knob to control the temperature pretty good. If I want to set the hot plate to 200C and keep it there for 40 minutes without it reaching 210C how can I do that? How can I make the electricity getting into the resistor wires just the right amount to make the temperature what I want it to be. Also I do not need a digital display I just need the knob to function with precision you know what I mean? Nothing fancy just a knob that can control the power which in turn would control the heat.

 

[Sceadwian]

Try Wikipedia. These devices and how they work down to an atomic level are fully covered already.

 

[adamalden]

Try Wikipedia. These devices and how they work down to an atomic level are fully covered already.

nothing showed up relating to my planned device. am I missing something? have you been to these links? if so can you post them for me and anyone with this interest? why are you guys holding out on me? just hand over the information...

 

[Sceadwian]

If you want that much simplicity as you don't seem to have a good grasp of the electronics the simplest thing I can think of is using a simple autotransformer.
2KVA 0-130VAC VARIABLE TRANSFORMER-MPJA, Inc. as an example.
That one's rated at 2000va which means 2000 watts, you could probably look around and find one cheaper that's rated to a more sane value, I dont' think you'd need more than about 500va or so (va = watts) The biggest problem would be designing your heating coil so that it could deliver that much power.

You would need a temperature probe in the beaker and then you just turn the knob till you get the temperature you want, it would be a little tricky to get it to actually hold the temperature automatically.

 

[adamalden]

If you want that much simplicity as you don't seem to have a good grasp of the electronics the simplest thing I can think of is using a simple autotransformer.
2KVA 0-130VAC VARIABLE TRANSFORMER-MPJA, Inc. as an example.
That one's rated at 2000va which means 2000 watts, you could probably look around and find one cheaper that's rated to a more sane value, I dont' think you'd need more than about 500va or so (va = watts) The biggest problem would be designing your heating coil so that it could deliver that much power.

You would need a temperature probe in the beaker and then you just turn the knob till you get the temperature you want, it would be a little tricky to get it to actually hold the temperature automatically.

WOW! That is exactly what I was looking for I just didn't know what it was... Thank you. Your right I don't know diddly about electronics but I hope to learn in the future. Thanks for the info. This device has just blown my mind... You could do all sorts of stuff with this!

 

[Sceadwian]

Yes, they go all the way down to 0 volts, and up to 20% over the mains voltage so they're extremely useful, relatively expensive though, and you're gonna pay a modest amount for shipping because of the weight, they're not light. You can actually find some that are rated for more power than that, but they're not commercial devices as I think the highest you can go on a 'consumer' devices is 2000V/A,