Capacitor bank question, series or parallel?

[gary350]

I have 34 capacitors they are all 7400. MFD 200 VDC with 250 VDC surge.

I want to connect them all together to deliver as much power as possible as quickly as possible. What is the best way to connect them all together.

I am going to use this for more than 1 project. 1 project will be a can crusher the other project will be a rail gun.

 

[crutschow]

If you want the highest current then connect them in parallel. The total capacitance is then the sum of all the capacitor values or 0.251F

 

[cachehiker]

Maximum discharge defined how? As far as energy goes, it matters not.

(1/2)(7400µF/34)(200V*34)(200V*34) = 5032 Joules at 6800 Volts.

(1/2)(7400µF*34)(200V)(200V) = 5032 Joules at 200 Volts.

 

[LukeeeeBennett]

What do you mean "largest amount of discharge"?

If you mean you want it to discharge as quick as possible then you'll want to look at the time constant. [LATEX]T=RC[/LATEX]. The total resistance * the total capacitance will give you a number which is the time taken for the capacitors to discharge to 37% of their maximum value. This is taken from the exponential function [LATEX]e^-1[/LATEX] as cap discharge is exponential. Therefore, try and get the resistors as low a value as possible.

If you want the largest current then you'll be using [LATEX]I=CV/t[/LATEX] in which case you'll want to put your caps in parallel (as crutschow stated) as they simply add up [LATEX](C1+C2+C3+C4)[/LATEX]. However in series they add like resistors in parallel [LATEX](1/C1 + 1/C2 = 1/C3 = 1/C4)[/LATEX].

 

[cachehiker]

Most can crushers and rail guns opt for the higher voltage so they're not stuck running 000 AWG cables.