Re: Reducing Inductance In Caps
In a message dated 2/17/00 2:13:10 AM Pacific Standard Time, tesla-at-pupman-dot-com
- snip -
> Hi Bill...
> many of the professional cap companies use this method it reduces the
> charge /discharge time by a few nanoseconds ( it reduces the inductance
> in the cap)
> not to sure what you mean by self resonance tho if you are refering
> to the resonance between the power supply and the main cap ... i dont
> think extended foil design makes a difference there
> Scot D
I had read that rolled caps self resonate, because they are a cap
and a coil all at the same time. However now I understand they must
have really meant that rolled caps have higher inductance. There
by slowing the charging and discharging time, that makes sense.
Now the question is if the inductance slows the charging and
discharging, would not that change the overall freq in the primary?
For TC use is it better to use extended foil design or the non
extended foil design in rolled caps?
Does this inductance change the overall capacitance?
Does it change the number of turns needed on the primary?
Many of us have built rolled poly caps. They work just fine in Tesla coil
service. While they certainly do have more internal inductance than
commercial end foil or flat plate caps, I think the performance difference is
very small. I have not noticed any significant difference in calculated
values (frequency, expected primary taping point, etc.) v.s. actual
performance. I have built three of these and considering time involved,
money spent, size, weight and ability to repair, I would definitely build MMC
caps next time.