Capacitorbank 11,3kJ bij 350V

My new capacitor bank is finished! This bank holds 38x 4700uF and 2x 3300uF capacitors of 350V in parallel (total 0,1852 Farad). It can hold a maximum energy of about 11344 Joule.

This bank is suitable for various electrical weapons and test setups, which include: rail gun, coil gun and ETC gun. The design is as compact as possible, so that it eventually can be made portable.

Specifications:

Capacitance: 185200uF
Voltage: 350V
Energy: 11343,5 Joules
Conductors: 4mm aluminum sheets
Weight: 44,1 kg
Dimensions: 385 x 613 x 182mm
Costs: €208,52

Video of two discharges:

It became obvious that the pneumatic switch did not work as well as I'd hoped, also a lot of the energy is dissipated on the contacts (not to mention the bouncing action of the contacts). I do have some high power hockey puck thyristors laying around. I will be using those for future experiments and hope that they can take the punch. A few photo's of the thyristors and my new connection wires of 50mm^2 and 70mm^2 insulated cable:

To get minimum resistance and inductance in the connections of the bank, I chose to use two plates as conductors. Two 4mm thick aluminum sheets separated by 1.5 mm PCB, the sheets are 385 x 613mm. Another advantage is that the capacitors are sufficiently supported this way. No further structural support is needed.

There is a metal distributor company in our village, which also delivers to individuals. They process metals and have a laser cutter to their disposal. So I called to find out what the material would cost, and what the laser cutting costs would be. The material only would be about 60 euro, but material and cutting would be 96 euros. For these 36 Euros extra you don't have to worry about cutting, drilling, etc. so it was quickly decided.

After laser cutting all I had to do was smooth off the edges! If you want something cut in a company like this you need a .dxf file. It is easy to create using AutoCAD. You can download all project files here.

I found a company on marktplaats.nl (digital market place) which offered used capacitors for €1.50 each. This is pretty cheap, so I bought their whole stock right away. These capacitors are about 70 euros new each. I bought a total of 34x 4700uF 250V, 38x 350V 4700uF and 26x 3300uf 350V (98 capacitors total from different vendors).

 

The total cost of the bank itself:

Item: Shop: Number:  Price:  Total:
4700uf 350V RIFA capacitor Marktplaats.nl 37        1,50      55,50
4700uf 350V EPCOS capacitor Marktplaats.nl 1        1,50         1,50
3300uf 350V SIEMENS capacitor Marktplaats.nl 2        1,50         3,00
Capacitor package transport Marktplaats.nl 1      25,00      25,00
2x 4mm aluminum sheets 385 x 613mm lasercut Vissertechniek 1      96,00      96,00
Print circuit board (PCB) 1 x 1m Marktplaats.nl 1      20,00      20,00
Metal screw m6x 20mm, 25pcs Toolstation.nl 3        1,98         5,94
Metal screw m5x 20mm, 25pcs Toolstation.nl 1        1,58         1,58
Total:          208,52

Some construction photo's:

Item: Shop: Number:  Price:  Total:
4700uf 350V RIFA capacitor Marktplaats.nl 37        1,50      55,50
4700uf 350V EPCOS capacitor Marktplaats.nl 1        1,50         1,50
3300uf 350V SIEMENS capacitor Marktplaats.nl 2        1,50         3,00
Capacitor package transport Marktplaats.nl 1      25,00      25,00
2x 4mm aluminum sheets 385 x 613mm lasercut Vissertechniek 1      96,00      96,00
Print circuit board (PCB) 1 x 1m Marktplaats.nl 1      20,00      20,00
Metal screw m6x 20mm, 25pcs Toolstation.nl 3        1,98         5,94
Metal screw m5x 20mm, 25pcs Toolstation.nl 1        1,58         1,58
Total:          208,52
Item: Shop: Number:  Price:  Total:
4700uf 350V RIFA capacitor Marktplaats.nl 37        1,50      55,50
4700uf 350V EPCOS capacitor Marktplaats.nl 1        1,50         1,50
3300uf 350V SIEMENS capacitor Marktplaats.nl 2        1,50         3,00
Capacitor package transport Marktplaats.nl 1      25,00      25,00
2x 4mm aluminum sheets 385 x 613mm lasercut Vissertechniek 1      96,00      96,00
Print circuit board (PCB) 1 x 1m Marktplaats.nl 1      20,00      20,00
Metal screw m6x 20mm, 25pcs Toolstation.nl 3        1,98         5,94
Metal screw m5x 20mm, 25pcs Toolstation.nl 1        1,58         1,58
Total:          208,52

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