I would like to fire a kA pulse from a capacitor bank. Datasheets usually mention ripple currents at various frequencies...but what about a short every now and then?
I work in industrial electronic equipment, electrolytics rarely fail shortcircuited, normally they leak the internal juice and or dry under normal conditions of use, but if they SC or explode may fe caused by an external faulty condition: overaged, overvoltage, overripple, etc.
They would have a short life. There are electrolytics specially designed for frequent fast discharge - they were used in photoflashes.
What is happening with that link.
The webpage was almost downloaded and suddenly swapped to WEBRING. I lost the intended page.
Is that a fault of the way I have my browser set up?
The webpage was almost downloaded and suddenly swapped to WEBRING. I lost the intended page.
Is that a fault of the way I have my browser set up?
Sure. They'll work for quite a while. We used to have a device we called the "spark-o-matic" back in the old college days - a bank of mis-matched soup can caps all bolted to bus bars and charged up to 50V thru a trafo, 25A block rectifier and a few colored PAR38's for a limiter. Never had a cap outright fail but after may sessions, they get weak. Dont do it with any caps you really care about - just surplus stuff you didn't pay full price for, are too low in voltage for any serious audio work, mis-matched, etc....
What was really a hoot was connecting one rail to an outlet box in the room with welding cable, and going out in the hall with the other and sparking it on the ceiling, light fixtures, etc. Cheap entertainment.
the voltage should be as low as possible. Otherwise I could use film caps or some special ceramic ones.
They don't need to last a lifetime. Surving a few hundred discharges would be good enough. I could live with a board exchange every year.
However if those electrolytics catch fire or burst up and disperse their evil innards all over the workplace, that would be unacceptable! 😱
No I don't think so, and anyway 1KA is not much, even for a modest capacitor bank.
Twenty years ago I had assembled an automatic reconditioning station for NiCad batteries based on half a dozen big 63V capacitors, a thyristor and an automatic charging/firing circuit.
It has been used for years, without failures or even noticeable weakening of the clearing pulses.
I had measured the peak output current, and it was in the KA range.
What happens when you subject ordinary lytics to high current pulses is the parasitic growth of a secondary layer, creating a parasitic series capacitor reducing the overall apparent capacitance.
Sort of bipolar capacitor by accident.
Normally, that parasitic capacitor has a much larger capacitance than the wanted one, and it stays that way unless non-linear effects caused by high currents polarize it, and make its value decrease.
That's about the only risk involved in what you intend to do, unless you repeat the charging/discharging cycle very quickly: this could lead to overheating and ultimately end with an explosion.
Photo flash capacitor have a construction minimizing the the build-up of a parasitic layer, but they only exist in high voltage versions.
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