Author Topic: Flashover  (Read 220 times)

Offline alan sailer

  • High Voltage Experimenter
  • **
  • Posts: 57
  • Karma: +5/-0
    • View Profile
Flashover
« on: May 04, 2021, 01:24:10 AM »
I am putting together a small/medium sized DRSSTC using SKM100 in a full bridge and a UD2.7C thru-hole
driver. The set-up is working to first order ie I am getting sparks and drawing current.

I was testing yesterday and I had a spark-over from the secondary to the primary. Didn't kill the IGBJTs
maybe because of the 44nF/3kV cap from buss negative to ground. This happened with a JAVATC coupling
of ~0.2. I do wonder if this hurt my secondary but the coil still coils.

The design I am using is closely based on OneKone's coil. To me the separation between the secondary coil
and the inner ring of the flat spiral primary has always seemed very tight. It is about 7-8mm.

It seems to me that with higher coupling factors the potential (ha) for flash-over gets greater.

Is there any guidance as to best practice? My past coils have all used an insulating lexan cylinder
with the primary wrapped in a rising spiral. This seems like a good idea but I have no experience
with DRSSTCs which involve higher voltages than my other coils.

My impression of DRSSTCs is that many people use the flat spiral and others use the inverted cone.
It seems like for all these designs an insulating lexan cylinder around the lower part of the secondary
would be a good idea.

Cheers.




Offline AstRii

  • High Voltage Technician
  • ***
  • Posts: 123
  • Karma: +3/-0
  • Czech Technical University in Prague
    • View Profile
Re: Flashover
« Reply #1 on: May 04, 2021, 09:56:30 AM »
0.2 coupling and only 8mm distance between primary and secondary asks for trouble.


It seems to me that with higher coupling factors the potential (ha) for flash-over gets greater.


That's a fact, higher coupling causes higher voltage/turn on the secondary coil. Once a certain critical threshold is exceeded, the secondary will flashover and it may even strike your primary, especially if your primary is so close to the secondary.
The coupling factor for a DRSSTC is usually around ~0.15, I would suggest decreasing coupling by making the inner most diameter of the primary bigger, which will even solve the tight proximity to the secondary.

Offline alan sailer

  • High Voltage Experimenter
  • **
  • Posts: 57
  • Karma: +5/-0
    • View Profile
Re: Flashover
« Reply #2 on: May 20, 2021, 04:09:18 AM »
I forgot to update and end this topic. I did decide to both lower the coupling and remove the primary inside turn to increase
the primary/secondary spacing.

I'm tuning the coil and have had no more flash-overs. Up to 27 inch sparks and expect more.

Thanks for the input.

Cheers.

High Voltage Forum

Re: Flashover
« Reply #2 on: May 20, 2021, 04:09:18 AM »

 


* Recent Topics and Posts

post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
Today at 01:06:02 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 12:44:31 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
Today at 12:41:33 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
Today at 12:11:13 AM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 11:52:11 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 11:38:44 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 10:26:51 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 09:57:56 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 09:29:08 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 08:53:25 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 07:22:05 PM
post Re: First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 13, 2021, 07:02:28 PM
post Re: HFSSTC with fixed crystal-controlled frequency
[Solid State Tesla Coils (SSTC)]
Steve Ward
June 13, 2021, 06:25:20 PM
post First middle sized DRSSTC - Phase lead tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Rapy2
June 13, 2021, 02:48:59 PM
post OpenTheremin v3 loosing calibration after minutes
[Electronic Circuits]
gianpaolo
June 13, 2021, 12:00:09 PM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Mads Barnkob
June 12, 2021, 07:28:03 PM
post Re: Rocket engine questions
[General Chat]
klugesmith
June 12, 2021, 07:23:12 PM
post Re: Rocket engine questions
[General Chat]
rikkitikkitavi
June 12, 2021, 12:24:06 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Da_Stier
June 12, 2021, 10:06:18 AM
post Re: Rocket engine questions
[General Chat]
plasma
June 12, 2021, 10:01:29 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Twospoons
June 12, 2021, 08:47:08 AM
post Re: What is the guidence on SpaceX rockets based on ? PID's?
[General Chat]
Patrick
June 12, 2021, 07:03:10 AM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
PEDRO HENRIQUE
June 12, 2021, 06:42:56 AM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
davekni
June 12, 2021, 04:20:53 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Willsmith001
June 11, 2021, 11:08:24 PM
post Re: How much propagation delay is too much propagation delay
[General Chat]
Willsmith001
June 11, 2021, 11:07:00 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
Da_Stier
June 11, 2021, 12:33:55 PM
post Re: Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
futurist
June 11, 2021, 12:03:24 PM
post Re: How much propagation delay is too much propagation delay
[General Chat]
davekni
June 11, 2021, 06:47:52 AM
post Re: How much propagation delay is too much propagation delay
[General Chat]
Power-Max
June 11, 2021, 06:32:02 AM
post Re: How much propagation delay is too much propagation delay
[General Chat]
davekni
June 11, 2021, 05:16:03 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
June 11, 2021, 04:53:50 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Hydron
June 10, 2021, 11:51:17 PM
post Re: Rocket engine questions
[General Chat]
MRMILSTAR
June 10, 2021, 09:52:59 PM
post Re: Rocket engine questions
[General Chat]
Patrick
June 10, 2021, 09:16:25 PM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Weston
June 10, 2021, 08:19:40 PM
post Fujifilm PMT module PMT12A, reverse engineering
[Detection, Counting and Measurements]
Mads Barnkob
June 10, 2021, 08:05:27 PM
post Nice PC Board Tesla
[Solid State Tesla Coils (SSTC)]
alan sailer
June 10, 2021, 07:46:12 PM
post Re: Is it possible to go fully CW with a DRSSRC?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
June 10, 2021, 06:31:40 PM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
rikkitikkitavi
June 10, 2021, 02:12:07 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
T3sl4co1l
June 10, 2021, 05:14:41 AM
post How much propagation delay is too much propagation delay
[General Chat]
Power-Max
June 10, 2021, 05:10:24 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Power-Max
June 10, 2021, 04:50:34 AM
post Re: SKM100 Mini DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
June 10, 2021, 01:36:31 AM
post Re: Why are SGT50T65FD1PN soo cheap on lcsc?
[General Chat]
Steve Ward
June 09, 2021, 09:15:22 PM
post Re: Is it possible to go fully CW with a DRSSRC?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Power-Max
June 09, 2021, 08:02:15 PM
post Re: Complications in the design of the first DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
PEDRO HENRIQUE
June 09, 2021, 07:17:27 PM
post Re: Analog HFBR amplifier
[Electronic Circuits]
Max
June 09, 2021, 06:58:33 PM
post Aisler PCB Manufacturer
[Printed Circuit Board]
Max
June 09, 2021, 06:58:12 PM
post [WTS] (US) Large Ferrite U and E Cores, assorted types
[Sell / Buy / Trade]
Steve Ward
June 09, 2021, 05:44:06 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