Author Topic: Mysterious Chinese HV capacitors  (Read 886 times)

Offline MRMILSTAR

  • High Voltage Engineer
  • ****
  • Posts: 217
  • Karma: +4/-0
  • Cedar Rapids, Iowa
    • View Profile
Mysterious Chinese HV capacitors
« on: October 15, 2019, 09:12:09 PM »
Has anyone used these capacitors in any projects? I have a 20-stage Marx generator that uses these capacitors and it seems to work fine with 12" sparks. I have been able to find out that they are metallized film polystyrene construction so they should be self-healing. I have the 2000 pF capacitance model but I have also seen a 3000 pF capacitance model. They are claimed to be rated for 30 KV. I may use these for a Cockroft-Walton voltage multiplier. I was also wondering if they would be good for tesla coil duty. I suspect not. The reason that they are so attractive is the price. They sell for about $2 on E-Bay. Here is an example E-Bay link.

https://www.ebay.com/itm/2000pF-30KV-DC-high-voltage-condenser-capacitor-for-marx-generator-hv-ham-rad-DM/273846620888?epid=9020951115&hash=item3fc287d2d8&_trkparms=ispr%3D1&enc=AQAEAAADMKvsXIZtBqdkfsZsMtzFbFsbX3WcW5fmB%2Fx7ZbaZTyexrltoT9Zyh679cvGbGwMYfnOzVcfPVaNgKYixjPpdJl0YwNeaSYUyV3otBZu3ZYDcVmPybi7BFy%2FqkKQ%2FXoJE1B58Hs5Tj1CBCPGp71SDQqnJANJyGaKGkGD3UH6GRGDoKnvqrn11vwktTOQJtVmPMdK7hH3NRVucDXxtUQxGjPvsZ5qO3GrqCyr7VxPr6Cn1jSMF9v8lPvSEllYdo6Nlw6EwkJ%2BuqnA%2FdTuKIiVFv6IVwC8DkrsXVPJxbYcvly8ui%2FeG%2BGsvmsK1r%2FiNIE3zz1d9OPlyebx%2FoP6AFdqizbhKjMM2s7a9x5lLi%2FACknZn80kRUMYaLP3L%2BmS0g5bmASQgTo1pSjtNUwv4Ei1%2BJKzkd4jzUeGb0ZKtSJL9a1rtOquNz%2BIXF6Q9imwLGTYs205qB9q3YCoJTYwpEmajnUV%2B9nt5U%2FVnV3lgaGwx1PfsUWUbI%2FvZ5e3Cd39%2BVX%2Fj6fh3y4EZijZ%2F2OhD%2FD0gR9pGV530LUTAg6L7%2B4QdGO9QH%2Fbs%2BR8WKcoTzXrdtbsq0Qnaw8E4uPzo4NYURtQoDklouTLld7itmAEPYKQ%2FOvJ656oGAnEf6v4DNBseFq0PBnImyiBrXr4HJMgrTBwZxazhCsNFgw90iTYhdemeKwQ0wG48tkvQ%2F7i8CrRkURjXGs7Ok1%2B8L6yxrusXrmRtlyR1y%2F8ShVe9grRIfyYNuzRFgWyXgNsH3JCC1HLiXY9vueXFa%2FJ9KlPiBacrcv9ojNXk00Z%2FaOojrrvTfsQWk13rqLW9NI6KhDLTLspcDMu0yYay9rGlTE9Y5GnCIKoOgDeUjmHZuyS%2BbpWgzmqDXwlOiRyiMFE1SNks9udhz6kXCBAe%2FJUEGQY5I3590%2F51yEHZAhP%2FlR4MGySdxQhKiE4UYEVZrgQ9yUs9Q0CB3dSOKNJyiRyBgg%2BLvGOB3HL%2FXgsKzRk%2FpqsgSinWcJMuLieharyJZaMnh3LLQ%2FJ%2FudGbaudBhyR06Qd%2B909Sjq9wsQr062lrMSP8rdU1mr4KkM%2Fgk8kKrkOssHGoEk3xJ3h0dw%3D%3D&checksum=273846620888c8316e1b54254e779cb82cf9e547cd63

Wow! That is certainly a long link.
Steve White
Cedar Rapids, Iowa
Retired electrical engineer

Online davekni

  • High Voltage Senior
  • *****
  • Posts: 691
  • Karma: +34/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Mysterious Chinese HV capacitors
« Reply #1 on: October 16, 2019, 03:33:52 AM »
These look exactly like the polystyrene capacitors I purchased on EBay 3 or 4 years ago.  They are very-low leakage, great for voltage-multiplier use.  However, they are foil, and have random tiny bubbles included, which form corona discharges in AC or pulse (Marx) use.  For low-frequency Marx use, they work OK.  My Marx generator recharges up to 120 times per second (plays low-register tunes).  In that use, they last a few minutes at most.  Same for AC (Tesla coil) use.
David Knierim

Offline MRMILSTAR

  • High Voltage Engineer
  • ****
  • Posts: 217
  • Karma: +4/-0
  • Cedar Rapids, Iowa
    • View Profile
Re: Mysterious Chinese HV capacitors
« Reply #2 on: October 16, 2019, 05:40:55 AM »
That's sort of what I thought. My Marx generator only produces a 12" spark about every 2 seconds although it is a very juicy spark. None of the caps have ever failed.

I have some spares of these capacitors. I have looked at the mounting of the leads and I can't quite see what is going on because even though the ends are clear, they are shaped sort of like a Fresnel lens which distorts what I can see. There appears to be schoopage of some sort of silvery material on each end which I assume is a conductor. There is one large axial lead on each end which makes sense. There is also an additional lead on each end made of very fine gauge wire. This smaller lead is connected to the larger lead and the other end appears to connect to the foil. I can't tell if the larger lead is connected to the schoopage or not. If not, then the entire current load must carried by the small leads. Maybe the large lead is just for mechanical strength for mounting. Some of the descriptions state that the large leads are for mechanical mounting strength but they don't say explicitly that they are also connected to the schoopage so that they can also handle the current.

Since they only cost $2 apiece, I'm tempted to sacrifice one of my spares by cutting those small leads to find out if I can charge the capacitor through only the large axial leads.

I've never seen a capacitor with a large lead and a much smaller lead on each end before. The construction of these capacitors are some of the reasons that these are a mystery to me.
« Last Edit: October 16, 2019, 05:48:19 AM by MRMILSTAR »
Steve White
Cedar Rapids, Iowa
Retired electrical engineer

Offline ElectroXa

  • High Voltage Enthusiast
  • *
  • Posts: 28
  • Karma: +1/-0
    • View Profile
Re: Mysterious Chinese HV capacitors
« Reply #3 on: October 16, 2019, 08:35:30 PM »
Hi
I've seen them on EBay, ant these caps were interesting for me, for a voltage multiplier
But partial discharges are a problem as davekni said, because  I planned to use them at 75 kHz and ~15 kV .
Does anyone already tested them at high frequency, to have a feedback before buying them ?

thanks a lot  :)
« Last Edit: October 16, 2019, 08:41:25 PM by ElectroXa »

Offline Experimentonomen

  • High Voltage Enthusiast
  • *
  • Posts: 6
  • Karma: +1/-0
    • View Profile
Re: Mysterious Chinese HV capacitors
« Reply #4 on: October 16, 2019, 08:41:05 PM »
Looks like inductive wind, so no good for anything above the audio range.

High Voltage Forum

Re: Mysterious Chinese HV capacitors
« Reply #4 on: October 16, 2019, 08:41:05 PM »

 


* Recent Topics and Posts

post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
panjaksli
Today at 07:34:53 PM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 07:14:18 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 07:05:18 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
panjaksli
Today at 06:58:40 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Max
Today at 06:56:50 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
profdc9
Today at 06:20:35 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
panjaksli
Today at 05:24:23 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
buchtawill
Today at 03:25:59 PM
post Re: Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
panjaksli
Today at 03:02:01 PM
post Have you ever tripped a breaker during normal operation ?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
panjaksli
Today at 01:36:04 PM
post Re: mini tesla (hopefully not a fail)
[Beginners]
bogdan
Today at 08:55:06 AM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
johnf
Today at 07:43:14 AM
post Re: How to design FPGA based on EDA technology?
[Electronic Circuits]
Genterman
Today at 06:53:52 AM
post Re: DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 03:29:14 AM
post Re: DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
buchtawill
Today at 02:43:33 AM
post Re: SKP DRSSTC = aliexpress driver + medium coil + large bricks ;)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Maju
December 01, 2020, 10:44:31 PM
post Re: mini tesla (hopefully not a fail)
[Beginners]
davekni
December 01, 2020, 07:44:14 PM
post Re: transistor markings question
[Beginners]
davekni
December 01, 2020, 07:39:48 PM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
December 01, 2020, 07:38:53 PM
post Re: How to design FPGA based on EDA technology?
[Electronic Circuits]
petespaco
December 01, 2020, 06:30:33 PM
post Re: Question about arduino polyphonic MIDI interrupter
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bozidar
December 01, 2020, 04:58:29 PM
post Re: Question about arduino polyphonic MIDI interrupter
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
December 01, 2020, 04:22:10 PM
post Re: Question about arduino polyphonic MIDI interrupter
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bozidar
December 01, 2020, 03:02:51 PM
post Re: Half-brigde with pot on mosfet gates question
[Solid State Tesla Coils (SSTC)]
TMaxElectronics
December 01, 2020, 12:08:56 PM
post transistor markings question
[Beginners]
NOOBPASTE51
December 01, 2020, 12:02:19 PM
post Re: Question about arduino polyphonic MIDI interrupter
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
December 01, 2020, 11:55:01 AM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
December 01, 2020, 11:50:19 AM
post Re: Analog HFBR amplifier
[Electronic Circuits]
TMaxElectronics
December 01, 2020, 11:21:56 AM
post Half-brigde with pot on mosfet gates question
[Solid State Tesla Coils (SSTC)]
costas_p
December 01, 2020, 11:17:16 AM
post Re: Question about arduino polyphonic MIDI interrupter
[Dual Resonant Solid State Tesla coils (DRSSTC)]
bozidar
December 01, 2020, 11:11:50 AM
post Re: mini tesla (hopefully not a fail)
[Beginners]
bogdan
December 01, 2020, 09:29:24 AM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
johnf
December 01, 2020, 07:03:56 AM
post Re: How to design FPGA based on EDA technology?
[Electronic Circuits]
johnf
December 01, 2020, 06:49:26 AM
post Re: SSTC or DRSSTC with GaN Transistors
[Solid State Tesla Coils (SSTC)]
Steve Ward
December 01, 2020, 04:59:28 AM
post How to design FPGA based on EDA technology?
[Electronic Circuits]
Genterman
December 01, 2020, 04:02:06 AM
post Re: DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
December 01, 2020, 03:46:10 AM
post Re: DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
buchtawill
December 01, 2020, 02:00:54 AM
post Re: HF Litz wire as a primary coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Steve Ward
December 01, 2020, 01:47:10 AM
post Re: DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
December 01, 2020, 12:02:23 AM
post Re: Site Info desperately needed: http://www.stevehv.4hv.org/
[General Chat]
Mads Barnkob
November 30, 2020, 10:28:56 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Miki_407
November 30, 2020, 08:58:41 PM
post DRSSTC trouble
[Dual Resonant Solid State Tesla coils (DRSSTC)]
buchtawill
November 30, 2020, 08:53:00 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
November 30, 2020, 08:49:30 PM
post Re: Simple H-Bridge construction with low parasitic inductances (for SSTC or ...)
[Beginners]
davekni
November 30, 2020, 08:45:46 PM
post Re: mini tesla (hopefully not a fail)
[Beginners]
davekni
November 30, 2020, 06:56:13 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Miki_407
November 30, 2020, 01:16:04 PM
post Re: I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
November 30, 2020, 12:56:05 PM
post Re: mini tesla (hopefully not a fail)
[Beginners]
bogdan
November 30, 2020, 12:03:06 PM
post I started making a drsstc
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Miki_407
November 30, 2020, 11:58:29 AM
post Re: Interesting 2400W power supply circuit
[Electronic Circuits]
Kiki
November 30, 2020, 07:58:52 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal