# Designing a HV generator for an ionic thruster

#### somedud

Joined Jul 10, 2023
8
So, me and a team of students has taken a project to build an ionic thruster and do some experiments on efficiency, thrust per watt, relations of thrust with voltage and other such things. I am responsible for managing the electronics and I've gotten stuck on the power supply.

In summary: the circuit I have in mind is a 12v 555 circuit found in some flyback drivers outputting a 12v 9Khz signal which is used to drive a mosfet and turn 220vdc into 220v 9Khz AC and put that into a self wound transformer to make 10kv 9Khz which would then be fed into a Cockroft-Walton generator and output 20,30,40 and 50kvdc with tiny amounts of current to create some wind.

We have first thought about rewinding a microwave transformer, but having 10kv with more than enough current and suitable frequency to kill you didn't seem like a good idea.

Would the circuit I explained and drawn a falstad simulation of actually work in real life, if not what would be the best way to get adjustable voltages of at least 30,40 and 50kv.
https://tinyurl.com/ykzbvau9 falstad is sometimes misinforming and inaccurate but I can't use better programs until I get my wifi sorted out.
Any help would be much appreciated

#### Alec_t

Joined Sep 17, 2013
14,314
thrust per watt
Thrust is a force: Watts specify energy. You would also need to know the ion velocity to calculate the energy involved.
How do you propose to measure the extremely microscopic thrust which your circuit would produce, and the ion velocity?
a self wound transformer to make 10kv 9Khz
Have you researched how such a transformer might be constructed?

#### Hymie

Joined Mar 30, 2018
1,284

#### somedud

Joined Jul 10, 2023
8
Thrust is a force: Watts specify energy. You would also need to know the ion velocity to calculate the energy involved.
How do you propose to measure the extremely microscopic thrust which your circuit would produce, and the ion velocity?

Have you researched how such a transformer might be constructed?
we are also planning to use the amount of air output using an anemometer, you are right we probably can't measure the ion velocity.

yes I have looked into winding the transformer but havent yet calculated the required wire thickness, for this purpose I would need a transformer with about 1:50 ratio. I plan to buy an empty core and wind it.

#### somedud

Joined Jul 10, 2023
8
These are actually the first options we considered!
Their output is a pulse rather than continuous, so it would make a noticeable difference in air output.
I apologize for forgetting to mention we are measuring air output, thrust per watt sounded like it made sense to me when writing the first post since i was reading a paper on ionic thrusters shortly before. sorry for the confusion

#### Hymie

Joined Mar 30, 2018
1,284
Although the HV units are listed as ‘pulsed’ I had one of the items in my second option, and the AC output was continuous (I suspect the same applies to the first option).

It maybe that the input current is pulsed, and sometimes ebay sellers don’t know the technicalities of what they are selling.

#### Danko

Joined Nov 22, 2017
1,835
So, me and a team of students has taken a project to build an ionic thruster and do some experiments on efficiency, thrust per watt, relations of thrust with voltage and other such things. I am responsible for managing the electronics and I've gotten stuck on the power supply.
You can obtain quite strong ionic wind, using low voltage, about 220V AC.
(Article below translated by Google from Russian):
=================================================
http://www.ra3tox.bget.ru/Sam/ostrie.html
"ULTRA SHARP NEEDLE
G. FREIBERG, teacher at MIPT

When the now world-famous Ukrainian master of miniatures Nikolai Syadristy first began to make an inscription on a cut grain of rice, it turned out that finding a suitable tool was not so easy. Even a sharpened steel needle was not suitable. The scratch from it was the same as if someone started writing in a student’s notebook with a paint brush. His search led him to ordinary river sand. Looking through individual grains of sand under a microscope, he selected several with sharp corners. With their help this unique work was accomplished.

And what should this sharpest point be? After all, under high magnification, a razor blade, the tip of a sewing needle, and even the edges of a grain of sand appear dull. In all of them, the tip ends in a sphere with a radius of about a thousandth of a millimeter. This sphere is formed from tens of thousands of atoms, and it is simply impossible to remove the extra layer of atoms manually. But this can be done very simply if you use electrochemical etching. Look at the picture. To make a point, the tip of which would be a hundred times sharper than a razor, you need: a small glass jar, a flashlight battery, a carbon electrode, a little plasticine and a piece of nichrome or manganin wire with a diameter of no more than 1 mm. A piece of an old spiral from an electric stove can also come in handy here.

Pour a 10% solution of alkali or hydrochloric acid into the jar. Assemble an electrical circuit. Turn it on. In just a matter of minutes you will see how the diameter of the wire in section AB begins to decrease. But closer to point A, the thinning of the wire occurs more quickly. Finally, a moment comes when the wire becomes so thin at this point that it breaks off under its own weight. The finished needle falls into plasticine. The tip is such that in a conventional microscope the sphere at the tip is no longer visible. After all, the tip itself ends with several dozen atoms. The quality of a manufactured tip can only be assessed using the voltage at which an electric discharge occurs directly in the air. The lower the voltage, the sharper the tip.

You can conduct very interesting experiments with manufactured needles. For example, a demonstration of ion wind. Take a long flat vessel. If you don’t have one, you can make the vessel yourself. To do this, you need a rectangular piece of glass and plasticine from which the side is made. Pour water into a vessel and launch a small boat into it. At its stern, install several needles connected by electrical contact with water. Place a long metal ruler over the boat. If we now apply voltage directly from the AC mains, then, due to the emergence of a reactive force from the ions breaking off from the tips, the boat will begin to move. This experience requires special attention and compliance with safety rules when working with live wires. Remember not to touch them during the experiment. You can only touch the switch. It is especially beautiful to watch the movement of the boat in a dimly lit room, when the electrical discharges are clearly visible.

_________"Ionic wind" - written on picture

The effect of air ionization near the tip is used to operate air ionizers (the so-called “Chizhevsky chandelier”). The proposed design of an ionizer chandelier will work better if the stationery pins are replaced with needles made in this way."
=======================================

#### Hymie

Joined Mar 30, 2018
1,284
Here is a youtube video of one of these high voltage generators producing a continuous arc.

#### somedud

Joined Jul 10, 2023
8
Here is a youtube video of one of these high voltage generators producing a continuous arc.

this video does a breakdown of these quite nicely, at 36:03 he says that there are 5-20ms between output discharges.
You can obtain quite strong ionic wind, using low voltage, about 220V AC.
(Article below translated by Google from Russian):
=================================================
http://www.ra3tox.bget.ru/Sam/ostrie.html
"ULTRA SHARP NEEDLE
G. FREIBERG, teacher at MIPT

When the now world-famous Ukrainian master of miniatures Nikolai Syadristy first began to make an inscription on a cut grain of rice, it turned out that finding a suitable tool was not so easy. Even a sharpened steel needle was not suitable. The scratch from it was the same as if someone started writing in a student’s notebook with a paint brush. His search led him to ordinary river sand. Looking through individual grains of sand under a microscope, he selected several with sharp corners. With their help this unique work was accomplished.

And what should this sharpest point be? After all, under high magnification, a razor blade, the tip of a sewing needle, and even the edges of a grain of sand appear dull. In all of them, the tip ends in a sphere with a radius of about a thousandth of a millimeter. This sphere is formed from tens of thousands of atoms, and it is simply impossible to remove the extra layer of atoms manually. But this can be done very simply if you use electrochemical etching. Look at the picture. To make a point, the tip of which would be a hundred times sharper than a razor, you need: a small glass jar, a flashlight battery, a carbon electrode, a little plasticine and a piece of nichrome or manganin wire with a diameter of no more than 1 mm. A piece of an old spiral from an electric stove can also come in handy here.

Pour a 10% solution of alkali or hydrochloric acid into the jar. Assemble an electrical circuit. Turn it on. In just a matter of minutes you will see how the diameter of the wire in section AB begins to decrease. But closer to point A, the thinning of the wire occurs more quickly. Finally, a moment comes when the wire becomes so thin at this point that it breaks off under its own weight. The finished needle falls into plasticine. The tip is such that in a conventional microscope the sphere at the tip is no longer visible. After all, the tip itself ends with several dozen atoms. The quality of a manufactured tip can only be assessed using the voltage at which an electric discharge occurs directly in the air. The lower the voltage, the sharper the tip.
View attachment 306365

You can conduct very interesting experiments with manufactured needles. For example, a demonstration of ion wind. Take a long flat vessel. If you don’t have one, you can make the vessel yourself. To do this, you need a rectangular piece of glass and plasticine from which the side is made. Pour water into a vessel and launch a small boat into it. At its stern, install several needles connected by electrical contact with water. Place a long metal ruler over the boat. If we now apply voltage directly from the AC mains, then, due to the emergence of a reactive force from the ions breaking off from the tips, the boat will begin to move. This experience requires special attention and compliance with safety rules when working with live wires. Remember not to touch them during the experiment. You can only touch the switch. It is especially beautiful to watch the movement of the boat in a dimly lit room, when the electrical discharges are clearly visible.
View attachment 306366
_________"Ionic wind" - written on picture

The effect of air ionization near the tip is used to operate air ionizers (the so-called “Chizhevsky chandelier”). The proposed design of an ionizer chandelier will work better if the stationery pins are replaced with needles made in this way."
=======================================
The sharpening technique is very interesting, we will definitely try it.

After the amount of research we did, using mains voltage to generate airflow sounds very counterintuitive, i believe it works as a proof of concept but would be underpowered for us.

#### somedud

Joined Jul 10, 2023
8
I want to build something similar to this circuit where the frequency is generated with a timer and dc is switched to 10khz then fed into a transformer.
Can I use this exact circuit but with a different transformer to make 10kvac 10khz and feed that to a CW multiplier to achieve 50kv
Can I separate the frequency generator and dc switcher sides having 220vac at the DC side to use a transformer with less ratio

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