|MadSci Network: Engineering|
I am trying to use capacitors instead of batteries to run electrical equipment. Let us say I am storing many thousands of amps on a capacitor. This amount of charge will destroy (and has destroyed) anything I connect it to. Is there anyway to discharge this electric potential slowly so as to be useful? This has been done in VCR's for years. If you move a VCR, and reconnect it to a power source within a limited amount of time, say, five to ten minutes, its memory is intact and it will remember the time and the programming. NO battery is involved. A capacitor based circuit is used to store the power needed to do that. So the short answer to your question is, yes, it can be done. What you have is a control problem. And, though the equipment may not exist to apply same technique used in low voltage circuits to a high power application, on paper, at least, it can be done. The voltage across a discharging capacitor follows an exponential curve. So one possibility is to use a variable resistor in series with the capacitor, with an appropriate control system programmed to decrease the resistance as needed to maintain a constant current drain from the capacitor. A drawback to using such a control is that for high current flows, a resistor would dissipate significant energy in the form of heat. It might be feasible, if the application can tolerate an AC supply to provide a variable inductor in parallel with your capacitor. Properly sized and controlled, the inductor - capacitor pair would set up a "tank" circuit that could be designed to oscillate at whatever frequency is tolerable. Here again, controlling the value of the variable inductor would be the difficult part. But the inductor would have a much lower heat dissipation level than the resistor. When you say that whatever you connect the capacitor to is "smoked," that indicates the need for proper insulation and components rated for high voltage service. As far as I know, the highest working voltage for power transmission lines is 750,000 Vac, and "lightening" test facilities go to higher voltages than that. That type of equipment isn't readily available, and it is expensive. But if your budget permits, you can accomplish the results you desire. Again, the control of the variable components is the key.
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