Author Topic: My terry filter  (Read 535 times)

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 79
  • Karma: +0/-0
    • View Profile
My terry filter
« on: October 11, 2019, 01:37:11 AM »
I have a couple of  30kv doorknob caps 500pf. With 15000 across them, that comes out to 3ma or 45watts that is prety hot. The fact that it is rated at 30kv does that mean it is good for the wattage. Never seen any with power rating on the ones on ebay.

Just did some testing and one good thing is its only 7500 across one cap to rf ground and after 5 min its just warm.

Also scored me a pig, only 7200 but it was free, so after get the current one going will switch over to pig power I just need Mrmlstar to roll me a big fat one, inductor.
« Last Edit: October 11, 2019, 02:11:13 AM by thedoc298 »

Offline MRMILSTAR

  • High Voltage Engineer
  • ****
  • Posts: 201
  • Karma: +4/-0
  • Cedar Rapids, Iowa
    • View Profile
Re: My terry filter
« Reply #1 on: October 11, 2019, 05:13:51 AM »
Ha ha. Start looking for those big E and I sections.

I use a low pass RC filter (so-called Terry filter) on my pole pig although it probably isn't necessary. I had the parts so why not, it can't hurt. I use two Murata 500 pF doorknob caps each rated for 30 KV, one for each leg of the HV output. These capacitors work with no problem with my 14.4 KV transformer output. My coil draws 6.5 KVA.

The capacitor spec you are looking for is continuous RMS current handling capability. Unfortunately, this spec is not always supplied. It is related to the capacitor's internal resistance. Doorknob capacitors generally have a very low internal resistance so they can handle a fair amount of continuous current. The biggest problem with them is that as they heat up, the capacitance can change. While important for a tuned circuit, it is non-critical for the single-pole low pass filter which is used for transformer protection.
Steve White
Cedar Rapids, Iowa
Retired electrical engineer

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 79
  • Karma: +0/-0
    • View Profile
Re: My terry filter
« Reply #2 on: October 11, 2019, 06:54:59 PM »
Ha ha. Start looking for those big E and I sections.

I use a low pass RC filter (so-called Terry filter) on my pole pig although it probably isn't necessary. I had the parts so why not, it can't hurt. I use two Murata 500 pF doorknob caps each rated for 30 KV, one for each leg of the HV output. These capacitors work with no problem with my 14.4 KV transformer output. My coil draws 6.5 KVA.

The capacitor spec you are looking for is continuous RMS current handling capability. Unfortunately, this spec is not always supplied. It is related to the capacitor's internal resistance. Doorknob capacitors generally have a very low internal resistance so they can handle a fair amount of continuous current. The biggest problem with them is that as they heat up, the capacitance can change. While important for a tuned circuit, it is non-critical for the single-pole low pass filter which is used for transformer protection.

I really appreciate all your help, just helps to have a second voice of someone that has done it before. I got that pig in my shop last night and could not believe how heavy they are. I use my welder for a ballast to test it out, still poped my 40 amp fuse after a bit.

High Voltage Forum

Re: My terry filter
« Reply #2 on: October 11, 2019, 06:54:59 PM »

 


* Recent Topics and Posts

post Re: compact midi interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
Today at 05:06:10 AM
post Re: Little Bee B Field / Current Probe
[General Chat]
Steve Ward
July 11, 2020, 10:23:24 PM
post Re: DRSSTC with litz-wire primary and 40 x TO247 IGBT H-Bridge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 11, 2020, 09:36:02 PM
post Re: Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Mads Barnkob
July 11, 2020, 07:36:23 PM
post Re: Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Fumeaux
July 11, 2020, 04:45:18 PM
post Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Mads Barnkob
July 11, 2020, 01:26:41 PM
post Re: Little Bee B Field / Current Probe
[General Chat]
Twospoons
July 11, 2020, 07:53:04 AM
post Little Bee B Field / Current Probe
[General Chat]
Weston
July 11, 2020, 06:37:03 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
klugesmith
July 11, 2020, 04:18:29 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
Twospoons
July 11, 2020, 01:35:07 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
klugesmith
July 10, 2020, 11:35:05 PM
post Re: Capacitors and arcs
[Beginners]
Morvandium
July 10, 2020, 11:10:57 PM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
Morvandium
July 10, 2020, 11:06:07 PM
post Re: Capacitors and arcs
[Beginners]
k42
July 10, 2020, 08:53:06 PM
post Re: XRay Tank- any ideas about what is inside
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 10, 2020, 07:20:48 PM
post Re: Why is Auto-transformer (variac) called transformer??
[Beginners]
Morvandium
July 10, 2020, 04:45:43 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
T3sl4co1l
July 10, 2020, 10:57:29 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 10, 2020, 08:55:30 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 10, 2020, 08:48:33 AM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
davekni
July 10, 2020, 07:00:13 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
davekni
July 10, 2020, 06:57:36 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
davekni
July 10, 2020, 05:44:54 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 09:23:38 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 09, 2020, 09:09:08 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 09, 2020, 07:00:49 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 09, 2020, 02:33:38 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 12:16:32 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 11:46:10 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
Twospoons
July 09, 2020, 10:56:18 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 08:37:52 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
klugesmith
July 09, 2020, 06:45:18 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 09, 2020, 02:36:22 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
Mads Barnkob
July 08, 2020, 09:43:20 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Morvandium
July 08, 2020, 09:33:35 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
johnf
July 08, 2020, 09:23:14 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
klugesmith
July 08, 2020, 09:16:42 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 08, 2020, 09:00:04 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
Mads Barnkob
July 08, 2020, 04:25:53 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
ElectroXa
July 08, 2020, 10:03:25 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 08, 2020, 08:39:10 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
Twospoons
July 08, 2020, 08:34:02 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
davekni
July 08, 2020, 04:39:10 AM
post Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 08, 2020, 12:46:23 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 10:28:37 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
ElectroXa
July 07, 2020, 10:09:22 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 09:36:53 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 07, 2020, 09:20:12 PM
post Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 07, 2020, 09:07:10 PM
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

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