How do you imagine to draw huge currents of a tiny capacitor? Remember: The capacity of 1F allows a current flow of 1A for 1 second. Vice versa you must pump 1A into the cap very fast to achieve that current flow.

May be you should try another approach. A nuclear power plant or something similar?

 

Did you read the entire thread?
We're talking about sine waves here.

__________________
Ron

 

Have you contacted this manufacturer?
http://www.vishay.com/capacitors/app-induction/
http://www.vishay.com/company/contacts/

 

yeah i did.

Vishay is a huge company with many branches and subdivisions, the particular division that makes induction heating capacitors is "Vishay ESTA".

ESTA is a highly specialized division and infact its so specialized that almost no distributor of Vishay parts distributes parts from that particular division. the one that i did find only sold in bulk. I'm still tracking down a distributor and still making calls. The fun part is that while many of them are helpful knowledgable people i eventually encounter someone along the chain that didn't even know they HAD an ESTA division and so communication has been slow, but its going.

The problem with being a huge multinational corporation is that you're a huge multinational corporation.

unfortuantely many of their capacitors are designed for medium frequency application (<100kHz) and are unusable in my setup because my inductor would then become unreasonably big.

things are going forward but i'm going to assume for now that i won't be able to find a single unit distributor of ESTA parts.

 

There should be a supply of spare parts available for cooking stoves now, that some of them have gone high tech. But I don't know what frequency they operate on. These capacitors must certainly have a large safety margin and it should be possible to operate them on a higher frequency at lower power level. Is your operating duty cycle going to be close to 100%?

 

Its a great idea to use replacement parts for induction cooktops as those capacitors can handle the current.

Induction cooktops run at 20kHz-50kHz and thus the capacitors might not handle my application.

but that being said, I did look into it. So far the only available replacement capacitors come integrated with the circuit board. cost of the complete assembly is twice the cost of me putting together the 100 caps or buying the pure capacitor from the before mentioned companies.

Nonetheless its still a good idea and if i could get my hands on a broken stove that still had a good circuit board then i might consider it.

If its rated for 500 amps then i might be able to push my 200 amps at higher frequency if i could cool them properly.


As for duty cycle, i'd need to know the specific capacitor specs to know if i'm getting too close to their maximum.

 

Here is another bad idea:

I know the construction differences between high current and low current capacitors.
Also between low ESR and high ESR, low ESL and high ESL.
Basted on the similarity of the above capacitors it is likely a very high current capacitor will work fine at high frequency even if it was not built for high frequencies.
Once upon a time I got a phase correction capacitor from the power company. They had 6.5kV and 12kV capacitors. I do not know the current rating but the wires going to the caps were 1” diameter. I know they were not built for 100khz and not characterized for high frequency but that may be because no one ever tried it. If I had one of these capacitors today I could test ESR and ESL.

What did I do with this cap? I built a 3,000 volt 6 amp supply.