Capacitors for Tesla Coil

[Rob76]

I bought 100 30 kv 102 ceramic caps the other week for my first TC, just finished soldering 3s9p bank.. I do wish I'd checked around the internet first as it seems they won't work well. Ah well.

Question though - Will submerging the cap bank in mineral oil improve performance at all? I'm still a way to go before I get the full coil up and running and don't wanna fork out more funds for better caps if these can still be used effectively.

Cheers!

 

[DerStrom8]

Hi Rob, welcome to ETO!

No, the mineral oil will not improve the performance of standard ceramic capacitors.

The concern about capacitors used in Tesla coils is the dissipation factor (The ratio of the ESR over the reactance of the capacitor). Higher dissipation factors can cause the circuit to operate inefficiently, leading to heating from the inside out. This won't be helped much (if at all) by mineral oil.

You really need some MKP or MMKP capacitors (metalized polypropylene). These tend to have much lower dissipation factors and are ideal for Tesla coil applications. The dissipation factor should be less than 0.001 in order for a given capacitor to work well in a Tesla coil primary tank circuit.

 

[DerStrom8]

Another question, what sort of high voltage transformer are you using that supposedly matches to a 3nF capacitor bank?

 

[shortbus=]

You really need some MKP or MMKP capacitors (metalized polypropylene)

Derstrom, and Rob, don't know if you know about this place, they have about the best price around for that type caps. They have all kinds of electronic stuff there too at good prices. And will ship worldwide. https://www.surplussales.com/index/Polypropylene-Polyester-Box-Type-Capacitors.html