Masuda Electric Dust (Re)mover

Thread Starter

jcatkeson

Joined Feb 10, 2023
14
Hi,

I'd like to build one of these:

https://phys.org/news/2006-04-lunar-buster.html

Basically it's a sort of static electricity linear motor that pushes dust around. I understand general principles of electronics and have built a few circuits from kits, but that's about it.

I figure this project will require a 3 phase signal generator and some way to amplify its output to a few hundred volts (and very low amps).

Can anyone suggest an inexpensive but useable 3 phase signal generator?

And what sort of components would you recommend for amplification?

Thanks,
John
 

SamR

Joined Mar 19, 2019
5,031
Your first problem to overcome is finding a 3-phase source... Most residential and commercial facilities are on a single-phase feed. Industrial large motors are typically 3 phase and large industry usually has 3 phase service.
 

SamR

Joined Mar 19, 2019
5,031
If <50mA @ Signal amplitude: 5 VDC, the most significant 5.0Vpp will do the job? Long ways from several hundred volts... good luck! Taking that signal and increasing voltage through a multiplier means losing amperage. Maybe there is a better way?
 

MisterBill2

Joined Jan 23, 2018
18,167
The cheap and simple way to create a higher voltage multi-phase signal is with a neon bulb circuit called a ring counter. In a ring counter each section is active in sequence around the ring. The versions that I have seen used NE2 neon bulbs and so the voltage was about 60 volts, and it was DC, as the application requires. Probably that same scheme can be scaled up with different gas tubes, although I do not have that information on hand. Other gases do have greater ionization voltages and so it should be possible to achieve without additional stages of boosting.
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
Can anyone suggest an inexpensive but useable 3 phase signal generator?
And what sort of components would you recommend for amplification?
Any BLDC motor will generate a 3ph sine wave output, they can be back-driven by any other small motor. DC or 1ph AC.
Chose one of a suitable Va.
 

MisterBill2

Joined Jan 23, 2018
18,167
I re-read the article in the first link and I see that they very carefully avoided giving any useful information, such as the voltage used or the actual frequency. But the wording is such that the lack of detail is smoothed over. So really the only part that was sort of definite was that it was a multi-phase voltage. So now we have the same details we had a year ago, which is none. Now we can see that the details needed to duplicate the experiment and verify the results are not given.
As for obtaining the higher voltage, the device to do that would not be an amplifier, at least not in this case. It would be very educational to find out those missing details from the originator of the article in the link.
 

Thread Starter

jcatkeson

Joined Feb 10, 2023
14
I re-read the article in the first link and I see that they very carefully avoided giving any useful information, such as the voltage used or the actual frequency.
I think you have a good grasp of the situation. I am reading about neon bulb ring counters now to learn how they work...

My strategy is to have a circuit where I can vary frequency and voltage across a wide swath, to experimentally find the 'sweet spot' where things work best. That said, we can make some assumptions.

From the photos it looks like the wires are about 1mm apart. The breakdown voltage at 1mm gap is 3,000 volts, so it has to be LESS THAN that or things will get sparky/flaming.
I've read that the minimal voltage for common static electricity (socks sticking together) is about 750 volts, so between that and 3 thousand, 1,000 volts would be in the right order of magnitude to start.

As for frequency, since this is mechanical movement it's not going to be in the RF range, but closer to low-end acoustic frequencies. Anything from 1hz to (pulling this one out of the air here) maybe 800hz is enough? We're not moving the dust at Mach 1 or anything, and even a slow creep would be acceptable for proof of concept.

Any BLDC motor will generate a 3ph sine wave output..
A back driven motor is an appealing idea because it's simple, and I can visually verify frequency by looking at the axle. My only concern is I couldn't vary voltage and frequency independently, because a faster spin would generate more power. Still, I might go that way, thanks for the suggestion.
 

MisterBill2

Joined Jan 23, 2018
18,167
Actually, a back-driven BLDC motor with three transformers could be the whole setup. The added advantage will be it is reversable, and easy to adjust the frequency as well.
Neon bulbs would produce a DC waveform, that is, a WAVEFORM WITH A DC offset.
A grid of wires spaced 1mm apart will be quite a task to create, if you want to make it any significant size. And I am trying to imagine a practical application for such a system.It comes across to me as another yootoob fraud.
 

shortbus

Joined Sep 30, 2009
10,045
Aren't you trying to develop something that is easily found online? There are many electronic modules available at low prices to create the negative ions that you need. Here is a link to a complete apparatus that does what your after - https://www.imagesco.com/kits/negative-ion-generator.html

Reading the link from the first post, it's just showing that the high voltage can be created from both single and three phase power. It doesn't use or need 3 phase to work.
 
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Thread Starter

jcatkeson

Joined Feb 10, 2023
14
.
A grid of wires spaced 1mm apart will be quite a task to create, if you want to make it any significant size. And I am trying to imagine a practical application for such a system.It comes across to me as another yootoob fraud.
Haha well if it's fraud it's NASA's own fraud:
https://science.nasa.gov/science-news/science-at-nasa/2006/19apr_dustbuster

The practical application is surfaces that clean themselves of dust.

As for making it, I can run 24 wires manually no problem. More than that can be a PCB.

First steps are just proof of concept. Practical application is getting ahead of myself at this point.
 

shortbus

Joined Sep 30, 2009
10,045
Yes I've seen those and know how they work. That's a completely different mechanism.
Did you carefully read your link? the only thing different is he used many unconnected (electricly) pins to generate the negative ions. It could be done by using "U" shaped conductors. The spark/plasma jumping from one to the next and so on until completing the circuit.

generator + U U U U - generator, like that
 

Thread Starter

jcatkeson

Joined Feb 10, 2023
14
Did you carefully read your link? the only thing different is he used many unconnected (electricly) pins to generate the negative ions. It could be done by using "U" shaped conductors. The spark/plasma jumping from one to the next and so on until completing the circuit.

generator + U U U U - generator, like that
I mean thanks for the link, no shade, but it's the same principle as Plasma Channel's ion thruster:

One key difference is the ion thruster moves air rather than dust. Another is that it runs electrical current through the air while Masuda's curtain (invented 1973) only runs current through metal wires, and can function in vacuum.
Ion thrusters are tens of thousands of volts higher too.

Ion air thrusters are really cool, but I'm not thrusting air ions, just dust.

Unless you are suggesting using this as a piece of something bigger?

(Edit) You know maybe that 7.5 kv power supply alone would be really useful, thanks for that lead...
 
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MisterBill2

Joined Jan 23, 2018
18,167
An interesting thing about that NASA article is that it repeatedly talks about an electromagnetic field moving the dust, which it is mentioned that the simulated dust contains no iron particles. I thought NASA used better proof readers.
And that "negative Ion Thruster" looks a lot like a compact version of the "electro-jet"that I assembled back in grade school. It used an oil burner transformer with a stiff wire that had a point on the end to spin a rotor that was about 5 inches across, that had two wires cut to points and bent about 90 degrees from the radius. So the electrostatic discharge from the points would make it spin, and in the dark thee was a faint purple glow in the circle it made.The only hard part was soldering the thin wire to the brass bushing that I used to keep it on the stiff wire. I was about 11 at the time. The transfromer was rated at 10,000 volts and 20 milliamps.But the center tap was tied to the case, I discovered years later. So the actual drive was only 5000 volts.
The "negative ion thruster" looks vastly overpriced, with a tiny encapsulated inverter/transformer similar to what us used in some commercial rat zappers, that sell for about $25.
 

shortbus

Joined Sep 30, 2009
10,045
One key difference is the ion thruster moves air rather than dust. Another is that it runs electrical current through the air while Masuda's curtain (invented 1973) only runs current through metal wires, and can function in vacuum.
First of I'm in no way talking about an "ion thruster". Please take the time to really read what they are talking about in YOUR link, in YOUR first post. Not just the first paragraph but the whole thing. Negative ion generators are used in HVAC to remove dust that gets past the filter. Back when people could smoke in restaurants and bars many of them had a negative ion air cleaner to take smoke out of the air.

Look at the illustrations in your link. It shows many individual pins/posts sticking up in the air. The text explains how a single wire didn't work to remove dust from solar panels. So he changed to a system that is like my "U's" in a line close together, that gave more places for the ions to work. If you don't think this Masuda curtain uses negative ions what do you think it's using?

And then your going to go into space? Earth isn't in a vacuum, so where will you use your experiment?
 

MisterBill2

Joined Jan 23, 2018
18,167
OK, after reading those two papers I see that a four phase system will be simpler because of the 90/1270 degree relationship . That can be provided from two transformers, both resonant, and having 1200 volt windings with the center-tap commoned. Only the second transformer will need to be fed through a quarter cycle phase delay, which will reduce the complexity of creating the hardware. probably it can be done without any active devices, making it rather straightforward to achieve. That would provide the four-phase 600 volt power shown in the research paper.
 

Thread Starter

jcatkeson

Joined Feb 10, 2023
14
Only the second transformer will need to be fed through a quarter cycle phase delay, which will reduce the complexity of creating the hardware.
Since every transformer's secondary is 90 degrees out of phase with its primary, maybe they can work in series? The first transformer would step up, the second would be 1:1. The first obvious problem with my suggestion is that it only works if transformers are perfectly efficient, which never happens. But here's a fake circuit diagram:

MasudaCircuit.png

(BTW output from transformer #2 will be in sync with mains. Useful or not?)
 

Thread Starter

jcatkeson

Joined Feb 10, 2023
14
Since every transformer's secondary is 90 degrees out of phase with its primary, maybe they can work in series?
Just correcting my own mistake here so not to spread misinformation. Transformers do NOT shift the phase of their output by 90 degrees.

So the above circuit would not work.
 
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