z pinch
Andy, Thu Dec 13 2012, 03:15AMI'm trying to create a magnetic pinch, below is some off the experiments I've done.
The coil is 40+30, with both south poles facing each other, the camera has a burning effect moving the spark outside the pipe.
This was with a 0.047uF cap measured from a multimeter at 20kv
Try a test with two mag same poles facing each other. It hasn't done what the top did, i'm guessing its the heat and amps that expands the air that force the plasma to follow the magnetic field.
This was with a 76pF cap measured from a multimeter at 20-40kv
This was with 0.006uF cap at 20kv,Will try the same setup but with 60-80kv when the parts arrive
The positive is connected to the larger diameter coil
The ground is connected to the larger diameter coil
Re: z pinch
Andy, Fri Dec 14 2012, 01:37AM
Theory post
Electrical conductive of a arc discharge, voltage drop across a arc, V = (I/A)(AR/d)(d)
Current in the arc as j =o*E ,o =E/j
o = 3×10−15
E = 20kv
j = 0.00000000006amps
Force on a charged particle, Fe = e*E+j*B
e = 1.60E-019
E = 20kv
j = 0.00000000006amps
B = 0.68Telsa
Fe = 0.0000000000408joules(2.5465e+8ev)
KE = 2.5465e+8
Andy, Fri Dec 14 2012, 01:37AM
Theory post
Electrical conductive of a arc discharge, voltage drop across a arc, V = (I/A)(AR/d)(d)
Current in the arc as j =o*E ,o =E/j
o = 3×10−15
E = 20kv
j = 0.00000000006amps
Force on a charged particle, Fe = e*E+j*B
e = 1.60E-019
E = 20kv
j = 0.00000000006amps
B = 0.68Telsa
Fe = 0.0000000000408joules(2.5465e+8ev)
KE = 2.5465e+8
Re: z pinch
Andy, Fri Dec 14 2012, 04:14AM
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Andy, Fri Dec 14 2012, 04:14AM
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Re: z pinch
Ash Small, Fri Dec 14 2012, 09:13AM
Any chance of some bigger pictures of that twisting arc, Andy?
(BTW, you ought to be updating the first post with progress as you go. It's fine using subsequent posts as you go, but progress should be posted in the first post using the edit function, so that people don't have to scroll through a long thread that could be pages and pages in order to see how the project is developing)
Ash Small, Fri Dec 14 2012, 09:13AM
Any chance of some bigger pictures of that twisting arc, Andy?
(BTW, you ought to be updating the first post with progress as you go. It's fine using subsequent posts as you go, but progress should be posted in the first post using the edit function, so that people don't have to scroll through a long thread that could be pages and pages in order to see how the project is developing)
Re: z pinch
Andy, Thu Dec 20 2012, 07:20AM
What pump could you use to make a vacuum?
Andy, Thu Dec 20 2012, 07:20AM
What pump could you use to make a vacuum?
Re: z pinch
Ash Small, Thu Dec 20 2012, 08:51AM
This depends on how hard a vacuum you require, but generally you'll need two pumps, a 'roughing' or 'backing' pump, eg a ratary vane pump, and a 'high vacuum' pump, either a diffusion pump or turbo-molucular pump. (for very high vacuums you'll also need an 'ion pump', or similar.
Turbo-molecular pumps are expensive (although there are occasional bargains on Ebay), fragile, and require expensive controllers (there are a few guides on the 'net for building your own).
I'd recommend a cheap diffusion pump from Ebay, and a rotary vane backing pump (diffusion and turbo pumps won't work at atmospheric pressure, they only work at pressures in the 'molecular flow' regime, so you need the backing pump tp 'start things off, and to 'back' the diff/turbo pump.
If you are in the US you probably want to be looking out for a Welch rotary vane pump, probably belt driven, if in UK, an Edwards unit.
Similarly, Veeco diff pumps seem easier to obtain in the US, and Edwards ones in the UK.
A two inch diff pump will be plenty large enough, smaller will probably do, but they are less common. Larger ones require more 'expensive' oil, and consume more power.
You'll also need vacuum guages, plumbing, etc. (and some form of 'chamber').
Ash Small, Thu Dec 20 2012, 08:51AM
Andy wrote ...
What pump could you use to make a vacuum?
What pump could you use to make a vacuum?
This depends on how hard a vacuum you require, but generally you'll need two pumps, a 'roughing' or 'backing' pump, eg a ratary vane pump, and a 'high vacuum' pump, either a diffusion pump or turbo-molucular pump. (for very high vacuums you'll also need an 'ion pump', or similar.
Turbo-molecular pumps are expensive (although there are occasional bargains on Ebay), fragile, and require expensive controllers (there are a few guides on the 'net for building your own).
I'd recommend a cheap diffusion pump from Ebay, and a rotary vane backing pump (diffusion and turbo pumps won't work at atmospheric pressure, they only work at pressures in the 'molecular flow' regime, so you need the backing pump tp 'start things off, and to 'back' the diff/turbo pump.
If you are in the US you probably want to be looking out for a Welch rotary vane pump, probably belt driven, if in UK, an Edwards unit.
Similarly, Veeco diff pumps seem easier to obtain in the US, and Edwards ones in the UK.
A two inch diff pump will be plenty large enough, smaller will probably do, but they are less common. Larger ones require more 'expensive' oil, and consume more power.
You'll also need vacuum guages, plumbing, etc. (and some form of 'chamber').
Re: z pinch
Daedronus, Thu Dec 20 2012, 09:35AM
Mechanical pumps are good down to micron (10^-3 torr) pressures (assuming they are in good condition with clean oil).
If you plan to use a diffusion/turbo pump the mechanical pump just needs to be large so it evacuates fast, it doesn't matter if it will only get to 100 microns.
Diffusion pumps need foreline pressure below 500 microns, more or less, it depends on the oil.
For a diffusion pump you also need a foreline trap (it can be just some copper sponge, anything that is vacuum compatible and is optically opaque) or the mechanical pump oil will eventually contaminate the oil in the diffusion pump.
From my experience I will tell you not to cheap out when it comes to vacuum seals, only use metal, or viton seals.
Daedronus, Thu Dec 20 2012, 09:35AM
Mechanical pumps are good down to micron (10^-3 torr) pressures (assuming they are in good condition with clean oil).
If you plan to use a diffusion/turbo pump the mechanical pump just needs to be large so it evacuates fast, it doesn't matter if it will only get to 100 microns.
Diffusion pumps need foreline pressure below 500 microns, more or less, it depends on the oil.
For a diffusion pump you also need a foreline trap (it can be just some copper sponge, anything that is vacuum compatible and is optically opaque) or the mechanical pump oil will eventually contaminate the oil in the diffusion pump.
From my experience I will tell you not to cheap out when it comes to vacuum seals, only use metal, or viton seals.
Re: z pinch
Andy, Thu Dec 20 2012, 06:08PM
Would this be a good pump, The turbo pumps are out of the price range. Is there any glue that could handle vacuum joining two perplex plastic together, would plain steel be alright for the chamber.
Andy, Thu Dec 20 2012, 06:08PM
Would this be a good pump
, The turbo pumps are out of the price range. Is there any glue that could handle vacuum joining two perplex plastic together, would plain steel be alright for the chamber.Re: z pinch
Daedronus, Thu Dec 20 2012, 09:58PM
A dry pump will not reach too much or a vacuum.
They can be used with a tubomolecular pump to get a 100% clean vacuum, since there is no oil. Oil in mechanical or diffusion pumps can reach in small amounts intro the chamber.
This can be stopped to large degree using optically opaque baffles.
But keep in mind that diffusion pumps are fine even for things like electron microscopes.
You would want a 100% oil free system if you make microprocessors or something, not common things.
What is your pressure target? that's the key question.
I know the thread is about a plasma Z pinch, but I have no clue in what kind of vacuum you want to use it.
Daedronus, Thu Dec 20 2012, 09:58PM
A dry pump will not reach too much or a vacuum.
They can be used with a tubomolecular pump to get a 100% clean vacuum, since there is no oil. Oil in mechanical or diffusion pumps can reach in small amounts intro the chamber.
This can be stopped to large degree using optically opaque baffles.
But keep in mind that diffusion pumps are fine even for things like electron microscopes.
You would want a 100% oil free system if you make microprocessors or something, not common things.
What is your pressure target? that's the key question.
I know the thread is about a plasma Z pinch, but I have no clue in what kind of vacuum you want to use it.
Re: z pinch
Andy, Thu Dec 20 2012, 10:39PM
I'm not sure the temperature of the arc, 2 psi should be alright i think. If I can get it down near there it will be cheaper to build a large cap than go lower in pressure.
Andy, Thu Dec 20 2012, 10:39PM
I'm not sure the temperature of the arc, 2 psi should be alright i think. If I can get it down near there it will be cheaper to build a large cap than go lower in pressure.
Re: z pinch
Daedronus, Thu Dec 20 2012, 11:02PM
2 psi is about 100 torr (100000 microns/mili torr).
Any 2 stage oil mechanical pump will easily go to 1 torr. (I'm not sure about dry diaphragm pumps).
At 1 torr you can use whatever materials you want, plastcs, epoxy, etc...
Below 100 mili Torr things get tricky.
I'm not sure how you come up with the 2 torr figure, why do you need a vacuum and not plain room pressure?
Daedronus, Thu Dec 20 2012, 11:02PM
2 psi is about 100 torr (100000 microns/mili torr).
Any 2 stage oil mechanical pump will easily go to 1 torr. (I'm not sure about dry diaphragm pumps).
At 1 torr you can use whatever materials you want, plastcs, epoxy, etc...
Below 100 mili Torr things get tricky.
I'm not sure how you come up with the 2 torr figure, why do you need a vacuum and not plain room pressure?
Re: z pinch
Andy, Thu Dec 20 2012, 11:23PM
Andy, Thu Dec 20 2012, 11:23PM
I'm not sure how you come up with the 2 torr figure, why do you need a vacuum and not plain room pressure?The electric field will accelerate the charge particles, say at 20kv to 83,876,580m/sec, but with the collisions at 1 atmosphere it drops down to 5032.5um/sec between collisions,kinetic energy of 0.000071eV, I need 15keV. If i could build 800kv power supply and the arc reach 0.5M degrees it should work, I think...
Re: z pinch
Ash Small, Fri Dec 21 2012, 10:30AM
I used to work for one of the leading suppliers of 'systems that make microprocessors' and, while we did supply oil free pumps sometimes, the vast majority of systems we supplied used backing pumps with oil in, although they did (without exception, I think) use a type of special 'Fomblin' oil.
Ash Small, Fri Dec 21 2012, 10:30AM
Daedronus wrote ...
You would want a 100% oil free system if you make microprocessors or something, not common things.
You would want a 100% oil free system if you make microprocessors or something, not common things.
I used to work for one of the leading suppliers of 'systems that make microprocessors' and, while we did supply oil free pumps sometimes, the vast majority of systems we supplied used backing pumps with oil in, although they did (without exception, I think) use a type of special 'Fomblin' oil.
Re: z pinch
Daedronus, Fri Dec 21 2012, 11:01AM
Back to the pump question, I would recommend a dual stage oil mechanical pump.
Newer and cleaner the better, but any should not have any problems to exceed the 2 psi requirement, in fact they should have no problem to get below 200 - 300 miliTorr.
If you get one used make sure to replace the oil with the proper kind.
Use any kind of 2 parts metal filled epoxy to make seals, but don't use silicone, the kind that out gasses acetic acid while curing. In fact don't use any kind of solvent or single part cure adhesive, because they tend to cure forever, outgs junk and they can contaminate the oil in the pump.
I would recommend to use a proper bellow connection to the pump, not a plastic hose.
They are quite cheap:
Daedronus, Fri Dec 21 2012, 11:01AM
Back to the pump question, I would recommend a dual stage oil mechanical pump.
Newer and cleaner the better, but any should not have any problems to exceed the 2 psi requirement, in fact they should have no problem to get below 200 - 300 miliTorr.
If you get one used make sure to replace the oil with the proper kind.
Use any kind of 2 parts metal filled epoxy to make seals, but don't use silicone, the kind that out gasses acetic acid while curing. In fact don't use any kind of solvent or single part cure adhesive, because they tend to cure forever, outgs junk and they can contaminate the oil in the pump.
I would recommend to use a proper bellow connection to the pump, not a plastic hose.
They are quite cheap:
Re: z pinch
Andy, Mon Mar 18 2013, 05:06AM
Working on a new area, A MHD thruster for a rocket. Being looking over the forum for can crushers, will try it with 10 microwave caps in parrellel for the coil and 10 in series for the spark gap, only collected 5. Running the nst looks like the prinpcile works :), just getting the amps will be the tricky part.
If any one reads this, what would be the effect of 10uF at 1kv for a can crusher, and would 15kv 100nF work as one. Getting the coil and spark to fire as one might be a problem
Just a test, will try with some more amps, F=I*Length*B, Increase the length of the arc and more current should make more of a jet outwards
This is useing a MOT, with a voltage doubler, I need more caps.... The MOT is running 240volt 2.5amps, this is the volatge doubler, going to need to put a switch to stop power flowing into the caps just before firing.
From the first post having wire charged and in a circle pattern makes it spin, adding some magnetic to add to the effect. Will try with the caps and see how much amps min needed to make the arc get close to 90 degrees
Andy, Mon Mar 18 2013, 05:06AM
Working on a new area, A MHD thruster for a rocket. Being looking over the forum for can crushers, will try it with 10 microwave caps in parrellel for the coil and 10 in series for the spark gap, only collected 5. Running the nst looks like the prinpcile works :), just getting the amps will be the tricky part.
If any one reads this, what would be the effect of 10uF at 1kv for a can crusher, and would 15kv 100nF work as one. Getting the coil and spark to fire as one might be a problem
Just a test, will try with some more amps, F=I*Length*B, Increase the length of the arc and more current should make more of a jet outwards
This is useing a MOT, with a voltage doubler, I need more caps.... The MOT is running 240volt 2.5amps, this is the volatge doubler, going to need to put a switch to stop power flowing into the caps just before firing.
From the first post having wire charged and in a circle pattern makes it spin, adding some magnetic to add to the effect. Will try with the caps and see how much amps min needed to make the arc get close to 90 degrees
Re: z pinch
Andy, Thu Apr 25 2013, 06:23AM
The ordering of CCTO didn't go through in the amount I wanted, but found this site , the Barium Titanate is $222 for 5kg, which I'm hoping to build 14*2 caps for a voltage multiplier running the NST.
Below is a experiment into a fuser which I plan to run from the CW, and the vacuum pump from the 5 above post.
This projects pretty much on hold for the CW.
Andy, Thu Apr 25 2013, 06:23AM
The ordering of CCTO didn't go through in the amount I wanted, but found this site
, the Barium Titanate is $222 for 5kg, which I'm hoping to build 14*2 caps for a voltage multiplier running the NST.Below is a experiment into a fuser which I plan to run from the CW, and the vacuum pump from the 5 above post.
This projects pretty much on hold for the CW.
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