ultra high current source

[alansimpson]

I am doing some experiments to measure magnetic fields and I want to generate a very high current 1kA for a brief period. How could I do this with easily available components.
Could be AC. Mains power supply is 220V
Thanks.

 

[VEBill]

Define 'brief'.

I saw an amateur mad scientist on TV that had a basement full of submarine batteries connected to a swinging bar that would short out to create ball lightning (or something that looked like ball lightning).

Also, Google can crushing and coin shinking.

 

[btrueblood]

Discharge from a large bank of capacitors.

 

[VEBill]

I spelled 'shrinking' incorrectly (just in case anyone is tempted to cut&paste the terms into Google).

 

[ScottyUK]

A current transformer energised from the mains on the secondary side would give you high current indefinitely on the primary. Any big toroidal transformer with a mains-rated primary and a single turn passed through it would give a similar effect to the CT - toroidals are available up to about 10kVA so you should be able to get a good few kA out of one into a single turn loop.


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If we learn from our mistakes I'm getting a great education!

 

[Skogsgurra]

1 kA isn't much. Any decent resistance welder produces 10 to 15 kA easily. A small one would probably suffice. Try any surplus store.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[davidbeach]

I agree with you Gunnar, I'm not sure how 1kA would even begin to be considered ultra high; lots of circuits run that much or more regularly.

 

[jimkirk]

What is your load impedance? What do you consider a "brief period"?

 

[itsmoked]

How long does a ball of plasma last jimkirk?

That reminds me. I saw a ball of plasma yesterday that was fueled primarily by the last quarter inch of my needle-nose pliers and all the hair on the knuckles of both hands.

I hate that old armor cabling, BX?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MikeHalloran]

Shorting a big NiCd cell will produce serious current.



Mike Halloran
Pembroke Pines, FL, USA

 

[bogeyman]

Shorting a big nicad will produce serious INJURY, to the cell or anybody near it.

 

[MikeHalloran]

Nah, it won't bother the cell, but it will melt your Crescent wrench.



Mike Halloran
Pembroke Pines, FL, USA

 

[Skogsgurra]

Don't try it at home!

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[VEBill]

For a few years, I had a NiCd battery in my car. A time-expired helicopter battery; drop in installation. As they say, 'Worked REAL good', even at -35C. Cold Cranking Amps appeared to be more-or-less infinite.

 

[MikeHalloran]

I wasn't intending to propose that one actually short the cell with a wrench, but to point out that even a single cell will feed a finite impedance (e.g. a contact or transistor and a fat wire) with substantial current.



Mike Halloran
Pembroke Pines, FL, USA

 

[melone]

alansimpson, please describe your requirements exactly so we can be helpful. Specifically, we need to know how much current, for how long.

Please be advised that you are asking for a dangerous setup, and you should not try any of the previous suggestions without full working knowledge of what you are doing. In other words, this kind of stuff WILL kill you if you don't know what you're doing.

 

[IRstuff]

A standard AA battery will dump more than 10 amps for about 15 seconds or so.

TTFN

FAQ731-376

 

[VEBill]

A long time ago, I did a short-circuit current test with a DVOM (10 amp input) across an alkaline D cell and saw only about 2A. I just repeated the test (just now) with an alkaline AA cell, and got 8.5A (wow!).

Maybe battery chemistry and design has improved over the years, or maybe the newer meters have a lower voltage drop across the 10A input.

 

[VEBill]

In the interest of safety, I do not recommend shorting out batteries with the 10A input of meters. Please do not try this at home. All sorts of bad things might happen.

 

[itsmoked]

It's my understanding that shorting a LiIon cell is a worse idea than shorting a NiCad.. (Worster?) LOL

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com