Author Topic: Mysterious Chinese HV capacitors  (Read 658 times)

Offline MRMILSTAR

  • High Voltage Engineer
  • ****
  • Posts: 201
  • 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

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 444
  • Karma: +25/-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: 201
  • 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: 25
  • 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: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
T3sl4co1l
July 06, 2020, 10:29:17 PM
post Re: induction heater troubleshooting help
[Electronic Circuits]
petespaco
July 06, 2020, 06:53:26 PM
post Re: adventures in homemade flyback bobbins.
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 06, 2020, 01:18:03 PM
post Re: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 06, 2020, 01:05:32 PM
post Re: Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
T3sl4co1l
July 06, 2020, 06:14:56 AM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 05, 2020, 06:31:21 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
HiVi
July 05, 2020, 12:30:02 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 10:35:50 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 04, 2020, 08:56:15 PM
post Re: Next Gen DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 04:37:32 PM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 04, 2020, 04:14:44 PM
post Dell PowerEdge M1000E Blade Server Teardown
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Mads Barnkob
July 04, 2020, 01:52:14 PM
post Help needed: HV Driver circuit
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 04, 2020, 12:37:48 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 04, 2020, 12:17:47 AM
post Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 03, 2020, 07:12:18 AM
post Re: What's needed to heat up 0.75 g of SiC (susceptor) mass until it turns dim-red??
[Radio Frequency]
klugesmith
July 03, 2020, 06:36:16 AM
post Re: IGBTs keep dying (un-solved again)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 03, 2020, 04:20:42 AM
post Re: "Slayer exciter" analysis
[Solid State Tesla Coils (SSTC)]
acmq
July 03, 2020, 03:01:56 AM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
July 02, 2020, 11:17:48 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
MRMILSTAR
July 02, 2020, 11:09:25 PM
post Re: Differential probe testing setup
[Laboratories, Equipment and Tools]
TMaxElectronics
July 02, 2020, 10:57:02 PM
post Re: Differential probe testing setup
[Laboratories, Equipment and Tools]
Twospoons
July 02, 2020, 10:47:18 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
johnf
July 02, 2020, 09:03:20 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
DJthefirst
July 02, 2020, 08:01:03 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 02, 2020, 07:04:55 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 02, 2020, 07:02:30 PM
post Re: IGBTs keep dying (solved for now)
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 02, 2020, 06:51:20 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
July 02, 2020, 05:34:23 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
DJthefirst
July 02, 2020, 05:09:09 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
TMaxElectronics
July 02, 2020, 12:51:29 PM
post Differential probe testing setup
[Laboratories, Equipment and Tools]
TMaxElectronics
July 02, 2020, 12:20:18 PM
post Re: How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
MRMILSTAR
July 02, 2020, 05:30:41 AM
post How to prevent secondary oxidation / Rust
[Dual Resonant Solid State Tesla coils (DRSSTC)]
DJthefirst
July 02, 2020, 04:16:58 AM
post Re: induction heater troubleshooting help
[Electronic Circuits]
petespaco
July 02, 2020, 01:02:02 AM
post Re: What's needed to heat up 0.75 g of SiC (susceptor) mass until it turns dim-red??
[Radio Frequency]
T3sl4co1l
July 01, 2020, 06:54:30 AM
post Re: "Slayer exciter" analysis
[Solid State Tesla Coils (SSTC)]
T3sl4co1l
July 01, 2020, 06:25:30 AM
post Re: "Slayer exciter" analysis
[Solid State Tesla Coils (SSTC)]
acmq
July 01, 2020, 02:47:13 AM
post Re: A three-phase "tree phase" Tesla coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Steve Ward
July 01, 2020, 02:43:34 AM
post Re: induction heater troubleshooting help
[Electronic Circuits]
aes92000
July 01, 2020, 02:33:07 AM
post Re: induction heater troubleshooting help
[Electronic Circuits]
petespaco
July 01, 2020, 12:03:08 AM
post Re: induction heater troubleshooting help
[Electronic Circuits]
aes92000
June 30, 2020, 10:34:36 PM
post Re: E-Bay Marx generator
[Voltage Multipliers]
ritaismyconscience
June 30, 2020, 09:14:06 PM
post Re: What's needed to heat up 0.75 g of SiC (susceptor) mass until it turns dim-red??
[Radio Frequency]
ritaismyconscience
June 30, 2020, 09:05:32 PM
post Re: induction heater troubleshooting help
[Electronic Circuits]
ritaismyconscience
June 30, 2020, 09:01:55 PM
post Re: A three-phase "tree phase" Tesla coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
June 30, 2020, 08:22:33 PM
post Re: "Slayer exciter" analysis
[Solid State Tesla Coils (SSTC)]
Weston
June 30, 2020, 07:54:40 PM
post "Slayer exciter" analysis
[Solid State Tesla Coils (SSTC)]
acmq
June 30, 2020, 05:13:57 PM
post induction heater troubleshooting help
[Electronic Circuits]
aes92000
June 30, 2020, 04:08:34 PM
post Re: 100$ Thermal Camera With 32x32 Pixel. HTi HT-02D Unboxing And Test
[Laboratories, Equipment and Tools]
Mads Barnkob
June 30, 2020, 02:54:22 PM
post Re: A three-phase "tree phase" Tesla coil
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
June 30, 2020, 01:04:30 PM

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