Cap Bank Discharge Rate with 300v Spikes - New Threader

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SUMMARY

The discussion centers on the challenges of discharging 300v spikes into a 4700 uF/400v capacitor bank using a 555 timer. Participants highlight the risks of using a 400v capacitor with a 300v source, emphasizing the importance of understanding the generator's current capability and the characteristics of the voltage spikes. The NE555 timer is noted to be unsuitable for voltages exceeding 30v, raising concerns about its application in this scenario. Overall, the conversation underscores the need for careful consideration of voltage levels and discharge methods in high-voltage applications.

PREREQUISITES
  • Understanding of capacitor discharge rates and energy storage
  • Familiarity with NE555 timer specifications and limitations
  • Knowledge of voltage spike characteristics and their impact on capacitors
  • Experience with high-voltage systems and safety precautions
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  • Research capacitor discharge calculations for high-voltage applications
  • Learn about alternative timing circuits suitable for high-voltage discharges
  • Investigate the current capabilities of generators producing voltage spikes
  • Explore safety measures for working with 400v capacitor banks
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Electrical engineers, hobbyists working with high-voltage circuits, and anyone involved in capacitor discharge applications will benefit from this discussion.

Dr. Mark Sexton
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I have created a generator outputting 300v spikes at 333 spikes per second. Wanting to discharge spikes to
4700 uF/400v capacitor bank and am having trouble calculating the cap discharge rate, and if a 555 timer is the appropriate tool for discharging the capacitance into an inverter. I am a new threader but I love listening to you guys input each other, especially when you disagree. Its like listening to Sheldon and Leonard! And I mean this in the most respectful way.
 
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Dr. Mark Sexton said:
I have created a generator outputting 300v spikes at 333 spikes per second. Wanting to discharge spikes to
4700 uF/400v capacitor bank and am having trouble calculating the cap discharge rate, and if a 555 timer is the appropriate tool for discharging the capacitance into an inverter. I am a new threader but I love listening to you guys input each other, especially when you disagree. Its like listening to Sheldon and Leonard! And I mean this in the most respectful way.

Welcome to the PF.

Sorry, what you wrote is confusing to me. Why try to drive voltage spikes into capacitors? That's not an effective way to charge them.

And what experience do you have with higher voltages? Charging a 400V cap with a 300V source does not leave a lot of margin. And that's a lot of energy storage -- what is this setup for?
 
Hi Mark. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

First, a 400v capacitor for a 300v spike sounds less conservative than I'd like. I enjoy fire crackers only on Guy Fawkes night.

A lot depends on the current capability of your generator: a single spike may fully charge the capacitor to 300v, or it may barely add any charge. Is that 300v measured when there is no loading, or is the generator able to deliver 300v into just a few ohms?

The NE555 works up to only 20 or 30v, so maybe you aren't expecting the capacitor voltage to exceed that?

You say a "spike", implying it's of short duration, but its duration is nevertheless important.

In summary, not enough information. :cool:
 
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