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Re: MMC Question.

Original poster: David Speck <Dave@xxxxxxxxxxxxxxxx>


The current most definitely does not remain at 60 mA throughout the tank circuit. A Tesla coil is a system with two modes of operation. While the primary cap is charging, yes, the current will approximate 60 mA, adjusted for the instantaneous voltage on the cap and the nonlinear characteristics of a magnetically shunted NST.

However, when the spark gap breaks down, the primary cap is discharged through the spark gap (very low resistance) into the primary coil, (also very low resistance), thus allowing the cap to discharge into something approximating a short circuit. If you note old postings, you will see builders who have measured primary currents in the hundreds of amps, even on modest coils, and kiloamps on big coils.
This is the reason you need beefy metal foil caps for a TC primary cap.
The metal film caps just can't handle the heavy discharge currents in most circumstances, unless very conservatively rated.
Wouldn't the current remain at 60mA throughout the tank?

I'm all ears, still learning so everything is educational at this point. As long as I don't stop my heart I consider it a learning experience. I would like to avoid the "power up and run for the hills" avenue as much as possible.