Drsstc tank Cap testing

[oneKone]

Hopefully this is in the correct section, I guess this could be spanned across a few sections.

Sometime ago I bought a "dawncap" from AliExpress, its finally arrived! The capacitor was sold as being 0.44uf, 6kv and a rating of *presumably* 60a rms current.

Currently (I haven't checked in a few months) there's no real information about these capacitors making them an unknown, hopefully this thread can give some information on them!

My plan is to replace the MMC in my drsstc 3 and put this single capacitor, and slowly ramp up bus voltage/on-time to see if/at what point the capacitor starts to heat. For me this is a simplistic approach, would there be a better way of testing?


Cheers.

[Weston]

Testing the capacitor with your DRSSTC driver would most closely match the usage in a DRSSTC, so it should work pretty good.

The capacitor should be pretty low loss, so if you wind a matching inductor it will take little energy to sustain the max current at resonance. If you wanted to be overkill you could probably do a test setup like this: https://highvoltageforum.net/index.php?topic=808.0

[Felix M.]

Hi oneKone,

This thread is pretty old but I'd still be interested in the resoults of your test. Those dawncaps are really cheap for what they are supposed to offer compared to other snubber caps used in larger MMCs. Do they match their specs?

Greetings

[Late]

Hi Felix
In my experience dawncaps have worked pretty well and with no issues. In my DRSSTC i have 2 220nF 6000VDC dawncaps in 2p config. And even when running the DRSSTC at 1kA peak 100-150uS on time for about 5-10mins they get barely warm. Cant say how accurate the current or voltage ratings are but the capacitance is basically spot on. They are a good option for tesla coils. Plan to use them in my DRSSTC II too.

[thedoc298]

Hopefully this is in the correct section, I guess this could be spanned across a few sections.

Sometime ago I bought a "dawncap" from AliExpress, its finally arrived! The capacitor was sold as being 0.44uf, 6kv and a rating of *presumably* 60a rms current.

Currently (I haven't checked in a few months) there's no real information about these capacitors making them an unknown, hopefully this thread can give some information on them!

My plan is to replace the MMC in my drsstc 3 and put this single capacitor, and slowly ramp up bus voltage/on-time to see if/at what point the capacitor starts to heat. For me this is a simplistic approach, would there be a better way of testing?


They have a complete specification sheet on the net, If I find mine I will post.


Cheers.

[Felix M.]

I'll hopefully finnish my first DR in the next few days/weeks with the completion of a solid state softstarter for the buscaps. I'm already planing my next DRs (two identical coils) and I might go for dawncaps then. It depends a bit on the Fres but they are an option. The current plan is to use some good WIMA FKP1. Thanks for sharing your experience Late.