4kj capacitor bank / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

4kj capacitor bank

1 2 next

Move Thread

LAN_403

Mads Barnkob

Mon Aug 06 2012, 11:00AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Its been a while since I have been posting about something I made, due to travelling most of the year in my new job.

So I am eager to show this neat little toy I have put together, further shots and measurements will have to wait a few weekends, if im lucky :)

The construction is similar to my smaller 333 joule MOC bank, trigger is made studier and the charger is better designed for the lower charging voltage.

The capacitor is a Maxwell energy discharge capacitor, so it is not a pulse capacitor. 2500uF at 1.8kV.

First shot at 1kj
2012 06 01 Steelwool

I really can not wait to get home to fire it some more and get some current measurements.

You can see it all at my site:

GrantX

Wed Aug 08 2012, 03:39AM

Registered Member #4074 Joined: Mon Aug 29 2011, 06:58AM
Location: Australia
Posts: 335

Very nice! That's a beastly capacitor, where did you find it?

This made me happy since I just purchased a 230v to 24v and a 24v to 575v transformer in order to build a cap charger similar to yours for some defibrillator caps I picked up on ebay this week :D

If my supply was going to remain connected to the caps while firing what sort of protection should I use? Some wirewound resistors?

brandon3055

Wed Aug 08 2012, 04:53AM

Registered Member #4548 Joined: Mon Apr 23 2012, 03:52AM
Location: tasmania
Posts: 271

Why not use a single 230 to 575 transformer?
You could probably use a large inductor for protection

GrantX

Wed Aug 08 2012, 06:32AM

Registered Member #4074 Joined: Mon Aug 29 2011, 06:58AM
Location: Australia
Posts: 335

Destroyer of mosfets wrote ...

Why not use a single 230 to 575 transformer?
You could probably use a large inductor for protection

Just trying to save money :p I did find a 230v to 575v 50VA transformer on ebay but they wanted $120 including shipping. the 2 transformers I ended up buying are 75VA and only cost $60 all up because of low postage charges.

Thanks for the tip, I'll try and find some suitable inductors.

Dr. Dark Current

Wed Aug 08 2012, 09:00AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Use a doubler.

Killa-X

Wed Aug 08 2012, 03:33PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Ahhn gotta love capacitor banks heh...I charge mine with a MOT...

What do you plan to use the bank for? Just blowing crap up or do you have specific projects like ETGs or rail guns?

Hope to see more :)

Mads Barnkob

Wed Aug 08 2012, 04:37PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Destroyer of mosfets wrote ...

Why not use a single 230 to 575 transformer?
You could probably use a large inductor for protection

I just used what transformers I could find in my stack of transformers, preferably some that was in bad condition, so its more coincidence than design.

Killa-X wrote ...

Ahhn gotta love capacitor banks heh...I charge mine with a MOT...

What do you plan to use the bank for? Just blowing crap up or do you have specific projects like ETGs or rail guns?

Hope to see more :)

For now it is just a powerful toy to blast some random stuff apart and to explore the world of one shot current measurements, do some different testing and at times I just need to build smaller "machines" inbetween the large projects.

Construction of a rail gun has to be rather sturdy and material cost vs. the heavy wear (blowing a part each shot) is not that appealing to me, bolting a new together with 50 screws for a shot... Which is why I would save the rail gun for when I have a 20 Ton press available, then just mount the loose parts in a heavy support structure from iron, isolated, and keep it together with pressure.

Hopefully I will do some shots on the upcoming saturday

Mads Barnkob

Sat Aug 11 2012, 03:50PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

The current measurements was done with a Pearson current monitor model 101 connected to a 10x probe and a Rigol DS1052e oscilloscope. Attenuation on the oscilloscope was set to 1x. So numbers should be multiplied by 10.

Current measurements of steel wool, 60 mm length, 10 mm diameter, with 4kj energy discharged. Measured peak current 29kA.

The voltage reversal could be worse, but will for sure shorten the lifespan of the capacitor.

You can see the rest of the pictures from the day and the lesser energy measurements here:

Mads Barnkob

Tue Nov 18 2014, 10:53PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

I had the capacitor bank out for a little fun :)

A 10A mini circuit breaker from a normal European household installation

Steelwool, recording seen through welders glass in the middle, you can see gas cloud.

200cm 0,25mm copper wire

A old iPod taking a blow

Ash Small

Wed Nov 19 2014, 07:02PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Immpressive stuff

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob