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Re: Bleeder Resistors



Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

I personally go through a discharge procedure and always keep the gap shorted between runs. Even with the use of a discharge circuit, the cap should be shorted just in the event a discharge network has failed unknowingly (before you go touching or tuning anything). A discharge network is an excellent safety precaution, but it can give a false sense of safety.

When power is disconnected and the cap is shorted, only then are the coil components safe to touch. At least, that's my rule of safety.

Take care,
Bart


Tesla list wrote:

Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:

Original poster: "Qndre Qndre" <qndre_encrypt@xxxxxxxxxxx>
Bleeder resistors are used to drain remaining charge from the capacitors in the tank circuit. If the remaining voltage after shutdown of the NST is too low to make the spark gap fire, the cap will not discharge into the primary and will hold a potentially lethal charge. A bleeder resistor across every single capacitor in the MMC will consume this charge turning it into heat which is better than having several kilovolts across the capacitors being available to shock you if you make adjustments to your system without shorting out every single cap. Furthermore a capacitor can regain charge from dielectric memory. The resulting voltage can exceed several hundreds of volts since there are so many capacitors in series in an MMC.


In any case, the primary coil and the power transformer short-circuit
the primary capacitor, so it can't hold any DC voltage between its
terminals while the system is interconnected. But if more than a single
big capacitor is used, as in an MMC, different leakages and rectification
by corona can generate voltages across the individual capacitors. The
voltages can reach dangerous levels, and can also damage the capacitors.
The dielectric memory, although I have never observed it, may also
cause the generation of stray voltages after the system is turned off.

Antonio Carlos M. de Queiroz