razor0109
Harmless
Posts: 20
Registered: 8-8-2018
Member Is Offline
|
|
[Nurdrage] Make Sodium Metal with Menthol - need help with DC motor
I ran into a problem with my crappy magnetic stirrer (12V DC 1A) as the magnesium ribbon pieces (where the shortness of each piece is a function of my
patience) clumped together too much, and the stirrer bar ended up being dislocated all the time.
I have a more powerful motor from a food processor that got fried out. It's rated for 230V DC circuits. I checked and there is voltage generated
between the leads while turning the motor manually, although I'm not sure if the motor could otherwise be damaged. I have almost zero experience with
building circuits, and I would need to make this motor turn with variable speed / get another, more powerful magnetic stirrer.
I have an Arduino Uno, with an L9110 DC Motor Driver.
Any guides, tips, even discouragement for planning to play with high current without reading a lot about the subject first would be much appreciated!
EDIT: could just a longer stirring bar solve the problem (reaction vessel would be an Erlenmeyer flask), and cutting the magnesium to really small
pieces? Also, the motor must run continuously for about 40 hrs. And, I do have a heating solution, I use an aluminium pot to contain the reaction
vessel, which has a PID controlled heating tape wrapped around it.
Motor type: BOSCH MMR150PLUS, which came from a Bosch MMR08A1 food processor.
URL to Nurdrage's video: https://www.youtube.com/watch?v=BsNoiFj3wlw
My stirrer: https://www.ebay.ca/itm/INTLLAB-Magnetic-Stirrer-Magnetic-Mi...
Arduino kit: https://www.ebay.com/itm/Adeept-Ultimate-Starter-learning-Ki...
[Edited on 15-3-2020 by razor0109]
|
|
|
Endo
Hazard to Others
Posts: 124
Registered: 5-1-2006
Location: USA
Member Is Offline
Mood: Cold
|
|
Unfortunately that motor will not work with the L9110 motor driver. The driver you have will supply from 2.5 to 12 Volts. It also maxes out at 800
milliamps. This means that the most it could supply to this motor is ~ 5% of it's rating. Not sure if you could even get any rotation out of it at
that low of an input. Further issue with the motor is it's duty cycle, running an intermittent duty motor for two or three days will lead to
overheating and destruction of your motor.
There are solutions out there, involving a stepper motor, appropriate power supply, and a stepper driver with appropriate hardware to supply it with a
timing signal. You can check out this thread for example SciMadness stirrer thread
The second part, the process outlined by Nurdrage is at elevated temperature. I doubt that you will see much of a reaction at room temperature.
By the time you go through all of that, and determine how to heat the pot too I think you might consider a new or used hotplate/stirrer combo.
Good luck!
|
|
|
NaK
Hazard to Self
Posts: 83
Registered: 12-9-2019
Member Is Offline
|
|
Well I actually tried the menthol method from the video and have to strongly advice against it: Quantities are very limited because you have to use a
lot of mineral oil for a small amount of reagent, otherwise the sodium globules won't collapse and you won't be able to extract anything and also
stirring a mineral oil solution with sodium pieces possibly unattended for multiple hours seems like a pretty bad idea.
I also didn't find a way to reuse the mineral oil or even dispose of it because there is no way of getting the magnesium oxide out.
I think the thermochemical way in the metal can is far superior, the yields are not as good but sodium hydroxide and magnesium are cheap and you won't
have to deal with all that mess. Only drawback is that you need dioxane but that's pretty easy to make from OTC chemicals
[Edited on 15-3-2020 by NaK]
[Edited on 15-3-2020 by NaK]
|
|
|
Sulaiman
International Hazard
Posts: 3554
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
I use a similar motor for my diy overhead stirrer
https://www.youtube.com/watch?v=ziRxiFSaZsA
d.c. motors have two main characteristics;
. speed proportional to voltage
. torque proportional to current
so even when operated at low speed, full rated torque is available.
(if power supply is adequate and the motor does not overheat)
I think that it will make an excellent stirrer motor.
- but consider the sparking of the commutator brushes as an ignition source.
_____________________________________________________________
P.S. providing the variable voltage for the motor can be achieved in many ways,
but first you need to know approximately what voltages and currents are required.
I guess that something like
https://www.ebay.co.uk/itm/Adjustable-AC-DC-Power-Supply-Ada...
or, more expensive but with many uses
https://www.ebay.co.uk/itm/LW-K305D-30V-5A-110V-DC-Power-Sup...
or
try a 5V usb charger, an old laptop charger, ac/dc plug-pack etc.
The flexible coupler is not necessary, but I think it is better than a rigid coupler.
P.P.S. making your mixture easier to stir is the cheapest solution,
and a larger stirbar will help.
P.P.P.S. lots of chemistry procedures rely upon your patience 
[Edited on 16-3-2020 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
There are various mains powered motor controllers available on eBay for controlling 240/120V DC brushed motors.
For example for about £8 https://www.ebay.co.uk/itm/AC-Input-220V-DC-Output-10-210V-2...
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
draculic acid69
International Hazard
Posts: 1371
Registered: 2-8-2018
Member Is Offline
|
|
Just buy a hotplate/mantle/stirrer off eBay for 100$ is the easiest solution.also if you're food processor was fried it's probably the motor that's
fucked so do you know if it even works
|
|
|
razor0109
Harmless
Posts: 20
Registered: 8-8-2018
Member Is Offline
|
|
What does the "L" and "N" leads do on this PWM speed controller?
|
|
|
wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
I would expect them to be the mains input which are the usual designations for Neutral and Live mains connections. The other two connections being
for the motor. Ideally there will be connection instructions with the controller or to be certain ask the seller if it comes with them or what they
are.
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
razor0109
Harmless
Posts: 20
Registered: 8-8-2018
Member Is Offline
|
|
Quote: Originally posted by wg48temp9  |
I would expect them to be the mains input which are the usual designations for Neutral and Live mains connections. The other two connections being
for the motor. Ideally there will be connection instructions with the controller or to be certain ask the seller if it comes with them or what they
are. |
I think i'm gonna go with your suggestion, and try with this PWM unit. Many thanks!
|
|
|
wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
Your welcome.
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
razor0109
Harmless
Posts: 20
Registered: 8-8-2018
Member Is Offline
|
|
Just one more thing; wouldn't I need to use an AC to DC rectifier, fitted on the output of the PWM for this? I have a DC motor!
|
|
|
wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
| Quote: Originally posted by razor0109 | [
Just one more thing; wouldn't I need to use an AC to DC rectifier, fitted on the output of the PWM for this? I have a DC motor!
|
I would think it was obviously not required if you have read the description and spec (shown below) for the item.
AC Input 220V DC Output 10-220V
PWM 220V DC Brush Motor Speed Controller
Specifications:
Input Voltage: AC 220V
Output Voltage: DC 10-210V Linear Under Load
Maximum Current Load: 20A
Continuous Current: 10A
Speed Range: 0% -100%
Regulation Method: Potentiometer
Connection Mode: Fence Type Terminal
Size: 85x57x37mm/3.35x2.24x1.46"
Quantity: 1 Pc
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
RogueRose
International Hazard
Posts: 1585
Registered: 16-6-2014
Member Is Offline
|
|
| Quote: Originally posted by Sulaiman | I use a similar motor for my diy overhead stirrer
https://www.youtube.com/watch?v=ziRxiFSaZsA
d.c. motors have two main characteristics;
. speed proportional to voltage
. torque proportional to current
so even when operated at low speed, full rated torque is available.
(if power supply is adequate and the motor does not overheat)
I think that it will make an excellent stirrer motor.
- but consider the sparking of the commutator brushes as an ignition source.
_____________________________________________________________
P.S. providing the variable voltage for the motor can be achieved in many ways,
but first you need to know approximately what voltages and currents are required.
I guess that something like
https://www.ebay.co.uk/itm/Adjustable-AC-DC-Power-Supply-Ada...
or, more expensive but with many uses
https://www.ebay.co.uk/itm/LW-K305D-30V-5A-110V-DC-Power-Sup...
or
try a 5V usb charger, an old laptop charger, ac/dc plug-pack etc.
The flexible coupler is not necessary, but I think it is better than a rigid coupler.
P.P.S. making your mixture easier to stir is the cheapest solution,
and a larger stirbar will help.
P.P.P.S. lots of chemistry procedures rely upon your patience
[Edited on 16-3-2020 by Sulaiman] |
Nice stirrer! I have a similar motor (probably identical, it's a 200w hand blender motor) that I could use but I was trying to figure out how to
control speed. What did you use? Are you running AC or DC? I'm guessing it's a universal motor?
I was thinking of using a router speed controller as it works on all universal motors I've tried, but it seems to have difficulty at lower speeds, say
anything under about 30-40% power, and at that speed it sometimes makes some bad noises (with vacuum cleaners/motors).
|
|
|
Sulaiman
International Hazard
Posts: 3554
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
You have quoted sufficient relevant information in your post above.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
razor0109
Harmless
Posts: 20
Registered: 8-8-2018
Member Is Offline
|
|
| Quote: Originally posted by wg48temp9 | | Quote: Originally posted by razor0109 | [
Just one more thing; wouldn't I need to use an AC to DC rectifier, fitted on the output of the PWM for this? I have a DC motor!
|
I would think it was obviously not required if you have read the description and spec (shown below) for the item.
AC Input 220V DC Output 10-220V
PWM 220V DC Brush Motor Speed Controller
Specifications:
Input Voltage: AC 220V
Output Voltage: DC 10-210V Linear Under Load
Maximum Current Load: 20A
Continuous Current: 10A
Speed Range: 0% -100%
Regulation Method: Potentiometer
Connection Mode: Fence Type Terminal
Size: 85x57x37mm/3.35x2.24x1.46"
Quantity: 1 Pc |
Fair enough, I was distracted by some other items I found on ebay.
The mains power here is supplied with a voltage rating of 230 V @ 50 Hz.
If the input of the PWM takes 220 volts, wouldn't it get overloaded with 230 volts? I am trying to find a PWM rated for 230 volts.
|
|
|
wg48temp9
National Hazard
Posts: 761
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
| Quote: Originally posted by razor0109 |
Fair enough, I was distracted by some other items I found on ebay.
The mains power here is supplied with a voltage rating of 230 V @ 50 Hz.
If the input of the PWM takes 220 volts, wouldn't it get overloaded with 230 volts? I am trying to find a PWM rated for 230 volts.
|
Unless a voltage rating specifies some like absolute maximum or even just maximum you should consider it a nominal rating.
For example.
fromAttachment: Explanation_230Volts.pdf (41kB)
This file has been downloaded 431 times
That means that something with a nominal 230V rating should be designed to operate correctly up to 253V. They are rms voltages the peak voltage would
be 358V pk. In addition there are voltage spikes on mains supplies and from the motor load. So the maximum voltage rating of the control element for a
230V mains may be 500V or even 1,000V depending on how generous the designer is with is his design margins.
In short a 220V controller will probably work just fine on 230V.
Particularly so as it will be passing at most a few amps and it is rated at 20A pk 10A continuous so it will not get very hot. High temperatures tend
to reduce maximum voltage ratings of electronic components.
PS: I have purchased one and I am in 240V land (UK) It will be controlling a DC brushed washing machine motor, probably a bit too powerful for a
stirrer unless its stirring concrete.
[Edited on 3/25/2020 by wg48temp9]
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
