1.5kJ Induction Launcher
Daniel Uhrenholt, Fri Nov 17 2006, 06:19PMHi all.
This project started out about 4 months ago, and now it is finaly working.
But I still need to get this thing outside to see what it can do, there is not sufficient room in my
apartment
It`s made out of 4 Siemens 350V 6000uF lytics in series-parallel to get 700V 6000uF, and a huge SCR and one fat diode.
The diode is a SD3000C10K and the SCR is a T9G0161203DH, both are huge PUCK style rectifiers
But i still need to make a stepup transformer so i can get this thing up to 700V
(A modified MOT with extra shunts and a new secondary)I will post a movie when i get it outside.
Some pics:
Setup on my bench in my bedroom
Let`s just say I made "some" marks in my ceiling
And thanks to Finn Hammer for helping me get the parts.
Cheers, Daniel
Mod edit: merged double post
The weather is bad here in Denmark, so i can`t get it outside yet...
But i have a question:
How can i calculate or measure the velocity of my projectile?
I don`t have a chronograph, and would like to calculate velocity and efficiencies with different Al. rings.
Daniel
Re: 1.5kJ Induction Launcher
Marko, Sat Nov 18 2006, 01:52PM
Why don't you just use a voltage doubler to charge to 700V?
You would need some kind of choke for current limiting but it's still lighter and less messy than mot..?
I like your housing of coil.. is that teflon box?
Marko, Sat Nov 18 2006, 01:52PM
Why don't you just use a voltage doubler to charge to 700V?
You would need some kind of choke for current limiting but it's still lighter and less messy than mot..?
I like your housing of coil.. is that teflon box?
Re: 1.5kJ Induction Launcher
Daniel Uhrenholt, Sat Nov 18 2006, 05:04PM
Hi Firkragg.
I don`t want to use a voltage doubler, because i think it is cooler and smarter to have a transformer with internal ballast. No need for a big charge resistor...(And just to say that i made it myself
)
But what the heck, i may try a voltage doubler just so i can fire it up to morrow!
But a choke or ballast would fill almost the same as a MOT or more, I only have some BIG ones to my classic Tesla coil experiments..
The coil form is made out of my favourite material POM, easy to machine and it can take some bumps.
And a little picture of the coil:
Cheers, Daniel
Daniel Uhrenholt, Sat Nov 18 2006, 05:04PM
Hi Firkragg.
I don`t want to use a voltage doubler, because i think it is cooler and smarter to have a transformer with internal ballast. No need for a big charge resistor...(And just to say that i made it myself
)But what the heck, i may try a voltage doubler just so i can fire it up to morrow!
But a choke or ballast would fill almost the same as a MOT or more, I only have some BIG ones to my classic Tesla coil experiments..
The coil form is made out of my favourite material POM, easy to machine and it can take some bumps.
And a little picture of the coil:
Cheers, Daniel
Re: 1.5kJ Induction Launcher
Marko, Sat Nov 18 2006, 05:25PM
I tought a doubler would be 'cooler and smarter', but do as you want.
Capacitive (small motor start cap), inductive (fluorescent or mercury lamp ballast, small transformers, etc.) or resistive (lightbulb?) ballasts would work well.
Nice coil indeed; be sure to have enough pressure n it to keep it in piece...
Marko, Sat Nov 18 2006, 05:25PM
I tought a doubler would be 'cooler and smarter', but do as you want.
Capacitive (small motor start cap), inductive (fluorescent or mercury lamp ballast, small transformers, etc.) or resistive (lightbulb?) ballasts would work well.
Nice coil indeed; be sure to have enough pressure n it to keep it in piece...
Re: 1.5kJ Induction Launcher
Daniel Uhrenholt, Sat Nov 18 2006, 06:12PM
Oki, I will try the doubler tonight if it possible with the parts i have.
I have 2 5600uF 400V DC electrolytcis, but i dont have many diodes... I have some from microwave ovens, but have no idea if they will work?
This will be my first voltage doubler...So it`s very new for me.
Do this look right?
But I will make my own transformer, because i only need to get the wire for it.
EDIT
I don`t think they will, they are rated 12000V 500mA
Daniel Uhrenholt, Sat Nov 18 2006, 06:12PM
Oki, I will try the doubler tonight if it possible with the parts i have.
I have 2 5600uF 400V DC electrolytcis, but i dont have many diodes... I have some from microwave ovens, but have no idea if they will work?
This will be my first voltage doubler...So it`s very new for me.
Do this look right?
But I will make my own transformer, because i only need to get the wire for it.
EDIT
I don`t think they will, they are rated 12000V 500mA
Re: 1.5kJ Induction Launcher
..., Sat Nov 18 2006, 06:33PM
5600uf is way too big, I try something like 500-1000ufd.
As to the diodes, a standard 1n4007 would work fine...
But looks good otherwise!
..., Sat Nov 18 2006, 06:33PM
5600uf is way too big, I try something like 500-1000ufd.
As to the diodes, a standard 1n4007 would work fine...
But looks good otherwise!
Re: 1.5kJ Induction Launcher
Daniel Uhrenholt, Sat Nov 18 2006, 06:47PM
What board? I don`t under stand
Oki about the voltage doubler, i have some 470uF 400V from a broken TIG welder i can use.
I`m scrap hunting twice a week
Daniel
Daniel Uhrenholt, Sat Nov 18 2006, 06:47PM
What board? I don`t under stand
Oki about the voltage doubler, i have some 470uF 400V from a broken TIG welder i can use.
I`m scrap hunting twice a week
Daniel
Re: 1.5kJ Induction Launcher
Coyote Wilde, Sat Nov 18 2006, 07:07PM
It all looks very sleek; good job.
As for measuring the velocity, once you get it outside you should be able to estimate the hight the projectile gets to; ignoring air resistance, you should be albe to get at least a first-order approximation with simple kinematics... and for a simple disk, the drag equations aren't too hairy either.
Coyote Wilde, Sat Nov 18 2006, 07:07PM
It all looks very sleek; good job.
As for measuring the velocity, once you get it outside you should be able to estimate the hight the projectile gets to; ignoring air resistance, you should be albe to get at least a first-order approximation with simple kinematics... and for a simple disk, the drag equations aren't too hairy either.
Re: 1.5kJ Induction Launcher
..., Sat Nov 18 2006, 07:53PM
Sorry, the refence to drilling to board was not realted to you (too many things going on at once)
As to calculatong the velocity of the disk, you will probably have to go for a photogate based cohornograph.
Have a led and a photodiode 1cm off the coil, and one 11cm away from the coil. You might have a hard time getting it to trigger well, but...
..., Sat Nov 18 2006, 07:53PM
Sorry, the refence to drilling to board was not realted to you (too many things going on at once)
As to calculatong the velocity of the disk, you will probably have to go for a photogate based cohornograph.
Have a led and a photodiode 1cm off the coil, and one 11cm away from the coil. You might have a hard time getting it to trigger well, but...
Re: 1.5kJ Induction Launcher
Reaching, Sat Nov 18 2006, 08:20PM
i have a velocity measurement circuit which is very accuratly and developed a new fotogate with IR diodes which can switch over a distance of about 10cm or more. the simulation of the fotogate shows that it can trigger up to a time of about 150µs , maybe you can use it for your ringlauncher to measure the exact velocity dont know how fast a ringlauncher projectile can be but up to a velocity of about 200m/s it should be no problem for the new fotogate
its in this thread but nobody seems to care , dont know if everybody here like complicated calculations
Reaching, Sat Nov 18 2006, 08:20PM
i have a velocity measurement circuit which is very accuratly and developed a new fotogate with IR diodes which can switch over a distance of about 10cm or more. the simulation of the fotogate shows that it can trigger up to a time of about 150µs , maybe you can use it for your ringlauncher to measure the exact velocity
dont know how fast a ringlauncher projectile can be but up to a velocity of about 200m/s it should be no problem for the new fotogateits in this thread but nobody seems to care , dont know if everybody here like complicated calculations
Re: 1.5kJ Induction Launcher
Simon, Sun Nov 19 2006, 01:09AM
The wiki has a page on coilguns with an overview of velocity measurement techniques. (There's also a ballistics page which goes into detail.)
See
I reckon you'd need to make something like a photogate for something of this power.
Simon, Sun Nov 19 2006, 01:09AM
The wiki has a page on coilguns with an overview of velocity measurement techniques. (There's also a ballistics page which goes into detail.)
See
I reckon you'd need to make something like a photogate for something of this power.
Re: 1.5kJ Induction Launcher
Daniel Uhrenholt, Sun Nov 19 2006, 10:37AM
Hi All.
The weather is good to day! But i doubt it has anything to do with I having birthday
I`m going to my parents house later to day, where i can do some shots with my baby!
Reaching your velocity meter looks great, do you have a parts list to it?
If it don`t work to my launcher i can use it later this year, i`m working on at 2 stage CG...
Well i dont have diodes to the voltage doubler, so i have to wait with the full power shots.. Damn!!
But i can get it to 420V DC with my variac, bridge rectifier and a filter cap
EDIT
380V DC (V*1.414) but my meter shows 450V DC I don`t get it...
EDIT again... 19/11 06
I did some shots today, but the Al. I used was waaay too heavy(227,6g). it jumped about 3-4 meters in the air
So later this week I will try again, with new discs i`ll make when i get to my workplace.
And I`ll get a new meter, i think the one i have is %¤#&/ up, and check my rectifier bridge( there must be something completely wrong, since i get 450V out of it)
Daniel
Daniel Uhrenholt, Sun Nov 19 2006, 10:37AM
Hi All.
The weather is good to day! But i doubt it has anything to do with I having birthday
I`m going to my parents house later to day, where i can do some shots with my baby!
Reaching your velocity meter looks great, do you have a parts list to it?
If it don`t work to my launcher i can use it later this year, i`m working on at 2 stage CG...
Well i dont have diodes to the voltage doubler, so i have to wait with the full power shots.. Damn!!
But i can get it to 420V DC with my variac, bridge rectifier and a filter cap
EDIT
380V DC (V*1.414) but my meter shows 450V DC
I don`t get it...EDIT again... 19/11 06
I did some shots today, but the Al. I used was waaay too heavy(227,6g). it jumped about 3-4 meters in the air
So later this week I will try again, with new discs i`ll make when i get to my workplace.
And I`ll get a new meter, i think the one i have is %¤#&/ up, and check my rectifier bridge( there must be something completely wrong, since i get 450V out of it)
Daniel
Re: 1.5kJ Induction Launcher
Jasonr, Tue Jan 09 2007, 02:59PM
What are the specs on that sweet looking coil? Turns? Layers? Diameter?
and also your results with sizes of Aluminum? thickness and shapes?
Jason
Jasonr, Tue Jan 09 2007, 02:59PM
What are the specs on that sweet looking coil? Turns? Layers? Diameter?
and also your results with sizes of Aluminum? thickness and shapes?
Jason
Re: 1.5kJ Induction Launcher
Daniel Uhrenholt, Wed Jan 10 2007, 08:50PM
Hi Jason
To be honest, I haven`t had the chance to get it outside yet. I don`t feel like setting it up on a wet lawn, and it`s winter here in Denmark now.
Or it supposed to be winther here, but there is like 10 degrees outside, and raining all the time
When the weather get`s better I will take it outside and set it up, with a Rogowski coil or a Pearson current transformer(If I can find one on Ebay).
I just bought a new Tektronix DSO, so now I can check the current pulse when I shoot
When it get`s outside, I will post the results here.
I really can`t tell you much about the coil, because it`s at my "test area" a few Km from where i live. `
Cheers, Daniel
BTW, nice rail gun you have there
Daniel Uhrenholt, Wed Jan 10 2007, 08:50PM
Hi Jason
To be honest, I haven`t had the chance to get it outside yet. I don`t feel like setting it up on a wet lawn, and it`s winter here in Denmark now.
Or it supposed to be winther here, but there is like 10 degrees outside, and raining all the time
When the weather get`s better I will take it outside and set it up, with a Rogowski coil or a Pearson current transformer(If I can find one on Ebay).
I just bought a new Tektronix DSO, so now I can check the current pulse when I shoot
When it get`s outside, I will post the results here.
I really can`t tell you much about the coil, because it`s at my "test area" a few Km from where i live. `
Cheers, Daniel
BTW, nice rail gun you have there
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