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Author Topic: Replication Attempt 2021  (Read 1578 times)
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Yo, so I'm going to try to replicate Spherics' tetra. Here is the schematic I'm working on. I need some help with the circuit before I go have a PCB made. If anyone wants to follow along I can get many PCBs made and sent out. I need help on the power supply and I need someone to check my work and make sure I haven't forgotten anything. I need bypass caps probably. I don't think this will be a fast enough circuit (frequency wise) so we'll need a bias around the entire unit.

I'll start mechanical construction tomorrow and post pictures if I get some progress.
   
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"BATT" is a 12V battery. For the 300V source, I have an electrophoresis supply but it's one of those smart ones that tries to think for you and so is very finicky. We can use batteries to get 300V. Or use batteries to get 48V and DC-DC to 300V? I want to make it safe so the circuit will probably need a switch or something to connect the batteries in series only when the board is powered. So you can disconnect/reconnect batteries without getting shocked. Main concern is safety on that power supply. Batteries with some HV bypass caps should be pretty stiff??
   
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"BATT" is a 12V battery. For the 300V source, I have an electrophoresis supply but it's one of those smart ones that tries to think for you and so is very finicky. We can use batteries to get 300V. Or use batteries to get 48V and DC-DC to 300V? I want to make it safe so the circuit will probably need a switch or something to connect the batteries in series only when the board is powered. So you can disconnect/reconnect batteries without getting shocked. Main concern is safety on that power supply. Batteries with some HV bypass caps should be pretty stiff??

What model EPS do you have?  I have an EC600-90 which is as you say, "smart".  Ion suggested back when that one can connect a dummy load resistor to the supply to defeat the low current condition and it then should operate as normal with current and load limitations.

Regards,
Pm
   
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Its a cheap chinese one, dont have it in front of me now. No parameters to change, just an "ON" button. EC600 would be very nice but I haven't gotten around to ordering one yet.
   

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tExB=qr
I use brick DC-DC converters for 2kv and 4kv with a circuit that ION gave me to regulate them.  EMCO makes them.
EMCO has regulated ones now: http://www.emcohighvoltage.com/regulated/caseries.php

(The big EPS's scare me...)

I recall Spherics saying that with the bias coil around the entire thing, you can get down to 3kHz (?)

Stability is very important.

Once I dig everything out and make some room, I'll do a parallel effort.

   
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Yes, he specified "high volts and amps" into the bias. Not quite sure quite how high "high" is, which is where most of the difficulty is with this. Once we can get ballpark figures for value we can start to refine our designs.

I'm going to order some EMCO bricks. My FETs can go up to 600 or so volts.

Some variables to find:

-Lowest possible voltage
-Lowest possible frequency (with and without bias?)
-Lowest possible bias setting for a given frequency

Further down the line I plan on doing some data collection on all the parameters to make this more repeatable for others.
   

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The regulator circuit that ION made for me:

This was for my EMCO F40.

I'll have to dig it out of a box to see what values I went with.
   
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Whoops, there is a mistake in my circuit and I am still working on it. Need an edge detector for the pulse generation circuit that only works low -> high. Replacing the two inverters and XOR gate with one inverter and an AND gate will work.
   

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tExB=qr
To make my ring counter auto-trigger, I used a:

SN74F260
DUAL 5-INPUT POSITIVE-NOR GATE

Note that I wanted 5-inputs because I was using 6 channels.
There is a 3-channel equivalent. Google:2-INPUT POSITIVE-NOR GATE
Maybe something like this: SN74F02
https://www.ti.com/product/SN74F02?utm_source=supplyframe&utm_medium=SEP&utm_campaign=not_alldatasheet&DCM=yes&dclid=CLuf8riW5-4CFWiDfwQd_34LYQ

Less than $1 each: https://www.mouser.com/Texas-Instruments/Semiconductors/Logic-ICs/Logic-Gates/SN74F02-Series/_/N-581zn?P=1yxz7teZ1z0zls6

The safety items that I ordered with the NOR gate are:
Mfr. #:   5KP100A
Desc.:   ESD Suppressors / TVS Diodes 100Vso 78VAC 28A

Mfr. #:   MOV-07D270K
Desc.:   Varistors 1800pF 27volts 10%

Mfr. #:   NVD14UCD120
Desc.:   Varistors 120Volt 14mm

These are in the AVEC schematic.
   
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Began working on the mechanical build today. Coils are 1000 ohms, turns unknown, 36 awg. They weight quite a bit. Building initial structure out of wood. Working out toroid dimensions. Tao magnetic diagram is helpful but still not sure of the exact height to place this thing. I'm going to glue together square pieces of wood to make a ring and then see if I can borrow a lathe to make it circular all the way around.

I found an EMCO 300V DC-DC converter that I can vary like Grumpy's big one. Very nice. Aiming for a 50 ns pulse width. Frequency still unknown. Need to make a form to wind the big outer SEP. Hopefully the pulse rate will be under 1Mhz as it seems to be the limit of most MOSFETs I've used when hard switching. I have a plan if I need to go higher but it's going to be a pain.

My coils are 2.5" dia, 3" long air core coils. Spacing to the center of the tetra ~4".
   

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Keep in mind that the supplied frequency is spread across the three channels.
The repetition rate at the coil is 1/3 of what you start with at the timer.
1MHZ at the coil is 3MHZ supplied to the counter.

You line up the outer sides of the top and bottom coils so they intersect of you project line from them.
There is another intersection point for the inner diameters of the coils.
So, there are two intersection points.
I doubt that the angle matters as much as it appears.

The induced coil is placed sort of between these intersection points.

Note that I call it the "induced coil", because it is.  It's not a collector after all.

   
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Keep in mind that the supplied frequency is spread across the three channels.
The repetition rate at the coil is 1/3 of what you start with at the timer.
1MHZ at the coil is 3MHZ supplied to the counter.

You line up the outer sides of the top and bottom coils so they intersect of you project line from them.
There is another intersection point for the inner diameters of the coils.
So, there are two intersection points.
I doubt that the angle matters as much as it appears.

The induced coil is placed sort of between these intersection points.

Note that I call it the "induced coil", because it is.  It's not a collector after all.

Thanks, I studied the diagram that tao made and I figured out a good way to approximate the size of the induced coil.

Just for reference my idea for increasing the rotational speed if needed is to round robin the mosfets. (Instead of one mosfet per phase there would be 2, or 3 or 4, etc. Pulsed sequentially each time that phase is triggered) Not going to bother until I try operation without a bias coil for testing.
   
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Please remove if ( for any reason)
I did read mention of member Tao
Tried to find him

Perhaps an invite to make him aware of new replication topic?

If any member has his contact please send to Peter ( Peter no longer has) so he can renew membership?
( I did discuss this with Peter today)
Also when forum rebooted few years back some members did not make it through reboot!
Many members do not care for recent political topics here and fell off ....
Now perhaps a refocus ?(on forum theme?)

Any persons you feel should be aware of new efforts here ( this thread ?)
Please forward contact to Peter for renewal!

Sorry for interrupting

Please feel free to remove post

With gratitude
Chet K

( also note to Grumpy and bte
May I mirror topic at other open source venue ?( there is moderated board at Stefan’s

Regardless
Thank you !!

Edit to comment below
Not appropriate to have discussion here

Topic was already discussed and our host wrote his preference and opinions

And they align with forum theme !
Not political blog.

Yes membership votes with feet ( I hear it all the time ( from actual experimenters not bloggers I don’t engage bloggers![/b]
« Last Edit: 2021-02-14, 21:24:59 by Chet K »
   

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Deleted off topic
« Last Edit: 2021-02-15, 17:32:17 by Peterae »


---------------------------
"The best teachers are those who show you where to look, but don't tell you what to see." - Alexandra k. Trenfor.
   
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Please remove if ( for any reason)
I did read mention of member Tao
Tried to find him

Perhaps an invite to make him aware of new replication topic?

If any member has his contact please send to Peter ( Peter no longer has) so he can renew membership?
( I did discuss this with Peter today)
Also when forum rebooted few years back some members did not make it through reboot!
Many members do not care for recent political topics here and fell off ....
Now perhaps a refocus ?(on forum theme?)

Any persons you feel should be aware of new efforts here ( this thread ?)
Please forward contact to Peter for renewal!

Sorry for interrupting

Please feel free to remove post

With gratitude
Chet K

( also note to Grumpy and bte
May I mirror topic at other open source venue ?( there is moderated board at Stefan’s

Regardless
Thank you !!

More help the better I suppose. As long as the topic doesn't get derailed. Need people to focus on the clear directions given by Spherics and making sure everyone has a build that is as close to tolerance as possible.

Build notes wise, I used a chop saw to get wood cut to the right angles (30 degrees) but I want more flexibility for adjustments.

My coils have a 1" ID, I have 1" dowel rod and the fit is snug. I'm going to drill holes on both ends of the dowel for a hinge and use some nylon/plastic threaded rod to adjust the height of both ends so I can adjust angles/height on the fly. The center toroid will be the most difficult still, I'm using a CAD program to determine the angles. I might just get one 3d printed in plastic to save time/headache.
   

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Buy me some coffee
Ah yes the good old tetra.
Coils
35SWG 1.85km 774 Ohms3.23Henrys

Still got it sitting on a shelf in my parents house.
   
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Attached is my CAD measurements for coil placement and sizing.
   
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Ah yes the good old tetra.
Coils
35SWG 1.85km 774 Ohms3.23Henrys

Still got it sitting on a shelf in my parents house.

Very nice build! Did the pyramid shape make finding the right angles easier?
   

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Buy me some coffee
I don't remember having trouble, too long ago for me to be sure.

My tetra was pre OUR so my build was at ou, never did post the results, never really had it run that well.

https://overunity.com/4297/complete-information-on-working-sm-style-device/msg139021/#msg139021

The pyramid was made of stiff card, held together with masking tape then filled with resin, incredibly easy to make and very strong, i would probably use a 3d printer and fill with resin if I were to build these days.
   
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I'm having the output coil fabricated due to the mounting complexity. Est 33 business days til completion. By the time it's here I should have a circuit board on the way and the 4 driving coils mounted.
   

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tExB=qr
I'm having the output coil fabricated due to the mounting complexity. Est 33 business days til completion. By the time it's here I should have a circuit board on the way and the 4 driving coils mounted.

Don't over-think this. Put a toroid coil where the other coils intersect.  Time is of the essence.

Get the driver working so you can get a rotating field.  This is the hardest part.  This field must be a radial electric field.  If you can't get this rotating field working, then the rest doesn't matter at all.

Stephan Marinov's MAGVID was similar but the coils were at 90 degrees.  No SEP coil and operated around 30 MHz.
   

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tExB=qr
Ah yes the good old tetra.
Coils
35SWG 1.85km 774 Ohms3.23Henrys

Still got it sitting on a shelf in my parents house.

That's a work of art.
Do you want to fire it back up?
   
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Don't over-think this. Put a toroid coil where the other coils intersect.  Time is of the essence.

Get the driver working so you can get a rotating field.  This is the hardest part.  This field must be a radial electric field.  If you can't get this rotating field working, then the rest doesn't matter at all.

Stephan Marinov's MAGVID was similar but the coils were at 90 degrees.  No SEP coil and operated around 30 MHz.

Yeah, good call, I'll get going on the other pieces ASAP. If spherics' device requires a similar frequency to the MAGVID (without a SEP), I won't be able to run it like that until I redo the circuit, and I don't want to do that now, so I'm going to put the SEP around the device entirely like he stated and hope it reduces the frequency requirements < 1Mhz per coil, 3Mhz at the oscillator. Almost ready to put in my component order.

30Mhz? I never saw a specific frequency mentioned when I read on that device. Do you have more info on it?
   
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Actually I just remembered, I already have a pulse driver. I'll cannibalize that and change the HV supply to use the EMCO device. Then once I finish mounting the coils I'll be in business.
   

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Yeah, good call, I'll get going on the other pieces ASAP. If spherics' device requires a similar frequency to the MAGVID (without a SEP), I won't be able to run it like that until I redo the circuit, and I don't want to do that now, so I'm going to put the SEP around the device entirely like he stated and hope it reduces the frequency requirements < 1Mhz per coil, 3Mhz at the oscillator. Almost ready to put in my component order.

30Mhz? I never saw a specific frequency mentioned when I read on that device. Do you have more info on it?

Without the SEP, it relies on a much weaker ambient field.

Can anyone guess what it is?

Here is a clue: the tetra without an outer coil (SEP) stops when flipped over.  So did the first TPU (video one that is).

I have a large zip file somewhere on the MAGVID, but I'd go with the Spherics stuff instead.  MAGVID had no output as it was for other purposes.

   
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