Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx> Hi Jim, Tesla list wrote:
Original poster: "Jim Mora" <mailto:jmora@xxxxxxxxxxx><jmora@xxxxxxxxxxx> In the same respect, the current can also be so small that it may take several cycles to reach the arc voltage *** we are talking peak to peak now, please help me understand how the primary cap is not forced to except a polarity reversal regardless what its level of charge is, based on the charge rate****.
The cap "will" see a reversal and it will continue to charge until the potential created by that charge is capable of breaking down the gap. The time it takes to charge the cap to break down potential is not dependent on the charging frequency. Imagine, instead of 60 hz supplied from the power company, we were supplied with 600 hz. In that situation, the cap charge time to a voltage is unchanged, however, reversals will occur 10 times more often than would the 60 hz source. When reversal occurs, the charge on the cap changes polarity at a rate determined by the source frequency. The cap charge is still there, thus there is a voltage across the cap and as the charge continues, the voltage increase continues on and is limited by the source potential or the gap breakdown voltage. In some cases, if the cap size is within resonant charging conditions and if the gap is too wide, the cap can charge to a voltage beyond the transformer output voltage (which can overvolt the transformer and cause breakdown in the transformers secondary winding). Thus, gap distance is very important and the installation of a Terry filter is cheap insurance to save a transformer.
Not sure if I supplied a suitable answer for you. If not, maybe you could further detail the question.
Take care, Bart