Author Topic: rotory spark gap  (Read 623 times)

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 65
  • Karma: +0/-0
    • View Profile
rotory spark gap
« on: July 03, 2019, 04:05:46 AM »
What is the material that the actual rotor is made from, can't find cause don't know what its called. The brown stuff is what im looking for but any will do. Thanks

Offline MRMILSTAR

  • High Voltage Technician
  • ***
  • Posts: 127
  • Karma: +4/-0
  • Cedar Rapids, Iowa
    • View Profile
Re: rotory spark gap
« Reply #1 on: July 03, 2019, 05:24:43 AM »
I use FR4 (also called GP03 or Garolite) with a thickness of 1/2 inch. It is an excellent insulator and is incredibly strong. The brown stuff is most commonly called Bakelite or phenolic. The FR4 is much stronger.
Steve White
Cedar Rapids, Iowa
Retired electrical engineer

Offline profdc9

  • High Voltage Engineer
  • ****
  • Posts: 232
  • Karma: +11/-0
    • View Profile
Re: rotory spark gap
« Reply #2 on: July 03, 2019, 06:03:20 AM »
FR4 is the circuit board material with copper on it.  G10 is the material without the copper (and usually the fire retardant).

https://en.wikipedia.org/wiki/G10_(material)

By the way balancing spark gap wheels is very tough.  I used an angle grinder for mine, and I destroyed the bearings on one trying to balance the wheel.   I made a paper template and stuck it on the wheel to get the spark points about in the right place, and then I placed on the arbor of the angle grinder and spun it slowly and used a file to grind the end off into a circle.  Make sure you are wearing protective gloves and face mask for sure.

Dan



Offline johnf

  • High Voltage Enthusiast
  • *
  • Posts: 33
  • Karma: +0/-0
    • View Profile
Re: rotory spark gap
« Reply #3 on: July 03, 2019, 08:40:34 AM »
The brown stuff is either paper reinforced phenolic or cloth reinforced phenolic typically used for electrical switch boards
it is self extinguishing and much cheaper than G10 hence the use in switchboards
ps the brown stuff is much easier on tooling unlike G10

edit goes under the trade name "Tufnol" and can be bought in tubes, rod, sheet
https://nz.rs-online.com/web/p/solid-plastic-sheets/1941148/ etc etc
« Last Edit: July 07, 2019, 12:34:34 AM by johnf »

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 65
  • Karma: +0/-0
    • View Profile
Re: rotory spark gap
« Reply #4 on: July 03, 2019, 12:05:47 PM »
Thanks for the info, im down to the rotor and the balanceing and have been dreading getting it right.

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1180
  • Karma: +17/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: rotory spark gap
« Reply #5 on: July 03, 2019, 03:03:44 PM »
Whatever material you end up using, spend a few minutes to calculate the speed at which the circumference of your RTG has, this should give you a good idea about how important sturdy materials and mountings are important for your own safety, as well as adding a blast shield around it to catch flying objects in the case of a failure.
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics

Offline MRMILSTAR

  • High Voltage Technician
  • ***
  • Posts: 127
  • Karma: +4/-0
  • Cedar Rapids, Iowa
    • View Profile
Re: rotory spark gap
« Reply #6 on: July 03, 2019, 05:26:05 PM »
I don't know what I was thinking when I wrote GP03. G10 was what I meant to say. GP03 is a red plastic material with fiber reinforcement which is also very good. I use that material for other things. It could also be used to make a rotor. Its a lot easier to machine than G10. If you use G10, be sure and use a breathing mask. Inhaling the glass fibers when cutting or grinding is hazardous, much like asbestos fibers.

The precision drilling of the holes for the motor shaft and electrodes is extremely important. If you do this step correctly, the vast majority of your balancing problem will be solved. I highly recommend a drill press to get accurate hole placement. Before you attempt to drill a hole, first use a starter bit. These are short, stiff bits used by machinists that will not flex and are designed for starting holes. After the hole is started, then switch to a regular twist drill bit. If you try to drill through G10 with only a regular twist drill, the hole location will likely wonder away from exactly where you want it when you try to start the hole. This will then greatly complicate your balancing problem.

Concerning balancing, here is the way that I did it. First, the rotor must be perfectly circular. A lathe could be used. At the time that I made my G10 rotor I did not have a lathe. I came up with an alternative that worked well.  First, I rough-cut the rotor on a band saw. I then made it as round as possible using the band saw but I didn't worry about perfection. I then mounted the RSG motor to the rotor. Next, I secured the RSG motor to a stable platform. I then used a die grinder attached to a stable moveable tool holder to grind the rotor perfectly round as I slowly turned the rotor by hand. You can essentially do the same process with a table router. Insure that your tungsten electrodes are as close to identical length as possible. I then used brass bolts with holes drilled down the middle to hold the tungsten electrodes. I drilled and tapped two screw holes in each bolt head for 2 allen head grub screws to secure the electrodes.

If you have done the previous work with precision, balancing should be fairly simple. You may need no additional balancing. I have 4 flying electrodes, so I just used trial-and-error. I started the RSG and noted the vibration. If there was excessive vibration I added a small washer to one electrode bolt and tried again. If the vibration got better I then moved the washer to another electrode location until I found the least vibration. After finding the location with the least vibration, I tried several different washer sizes on that location until I found the one with the least vibration. It sounds tedious but it really didn't take that long. If you can make a good knife-edge balance, that would be a great way to balance it also but I didn't have one. I figured I could get it balanced by trial-and-error faster than it would take me to make a good knife-edge balance.
« Last Edit: July 07, 2019, 05:46:55 PM by MRMILSTAR »
Steve White
Cedar Rapids, Iowa
Retired electrical engineer

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 65
  • Karma: +0/-0
    • View Profile
Re: rotory spark gap
« Reply #7 on: July 06, 2019, 02:21:20 PM »
Thanks for all the tips, I have a syncronous 3600 motor and going with 120 bpm. Being able to get great tips like these, I belive I will succeed. So far everything has been fun.

Offline thedoc298

  • High Voltage Experimenter
  • **
  • Posts: 65
  • Karma: +0/-0
    • View Profile
Re: rotory spark gap
« Reply #8 on: July 06, 2019, 04:00:03 PM »
Meant to say 120 bps :)

High Voltage Forum

Re: rotory spark gap
« Reply #8 on: July 06, 2019, 04:00:03 PM »

 


* Recent Topics and Posts

post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
MRMILSTAR
Today at 05:19:51 AM
post Re: High voltage Christmas ornaments
[Light, lasers and optics]
klugesmith
Today at 04:57:27 AM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
T3sl4co1l
Today at 04:04:35 AM
post Re: High voltage Christmas ornaments
[Light, lasers and optics]
John123
Today at 03:29:26 AM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
klugesmith
Today at 01:14:06 AM
post High voltage Christmas ornaments
[Light, lasers and optics]
klugesmith
Today at 12:03:49 AM
post Small 65Kv X Ray Transformer hosuing build
[Transformer (iron core)]
DashApple
December 14, 2019, 10:52:49 PM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
johnf
December 14, 2019, 09:23:27 PM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
MRMILSTAR
December 14, 2019, 09:12:47 PM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
johnf
December 14, 2019, 09:07:42 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
MRMILSTAR
December 14, 2019, 09:04:49 PM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
MRMILSTAR
December 14, 2019, 08:32:36 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
klugesmith
December 14, 2019, 07:01:18 PM
post Re: Mineral oil breakdown voltage
[Voltage Multipliers]
klugesmith
December 14, 2019, 06:21:27 PM
post Mineral oil breakdown voltage
[Voltage Multipliers]
MRMILSTAR
December 14, 2019, 05:00:39 PM
post Re: QCW ramp generator
[Dual Resonant Solid State Tesla coils]
hammertone
December 14, 2019, 03:05:48 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
T3sl4co1l
December 14, 2019, 05:45:54 AM
post Re: Modern go-to switching devices
[Beginners]
T3sl4co1l
December 14, 2019, 05:37:17 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
davekni
December 14, 2019, 05:26:41 AM
post Re: Modern go-to switching devices
[Beginners]
klugesmith
December 14, 2019, 04:54:15 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 14, 2019, 02:30:40 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
jturnerkc
December 14, 2019, 02:21:19 AM
post Re: Aethra CCD Webcam Teardown - From Back When Streaming Was Expensive!
[Electronic circuits]
John123
December 14, 2019, 02:14:48 AM
post Modern go-to switching devices
[Beginners]
John123
December 14, 2019, 01:54:55 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 14, 2019, 01:37:03 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 14, 2019, 12:57:15 AM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
MRMILSTAR
December 13, 2019, 11:48:12 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 13, 2019, 11:19:27 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
John123
December 13, 2019, 11:00:18 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 13, 2019, 10:50:03 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
MRMILSTAR
December 13, 2019, 10:46:20 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
klugesmith
December 13, 2019, 10:31:03 PM
post Re: Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
AndreiRS
December 13, 2019, 10:00:04 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
John123
December 13, 2019, 09:08:28 PM
post Unusual polarized non-electrolytic energy discharge capacitor
[Capacitor banks]
MRMILSTAR
December 13, 2019, 09:06:47 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
MRMILSTAR
December 13, 2019, 08:56:27 PM
post Re: SGTC MK1 - An Accomplishment in Progress
[Spark gap Tesla coils]
jturnerkc
December 13, 2019, 05:05:55 PM
post Re: How do you keep in contact with forum people...?
[General chatting]
Mads Barnkob
December 13, 2019, 09:31:58 AM
post Re: My first DRSSTC on bricks
[Dual Resonant Solid State Tesla coils]
johnf
December 13, 2019, 07:56:39 AM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
AndreiRS
December 13, 2019, 03:59:49 AM
post How do you keep in contact with forum people...?
[General chatting]
AndreiRS
December 13, 2019, 03:23:31 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
klugesmith
December 13, 2019, 12:16:53 AM
post Re: My first DRSSTC on bricks
[Dual Resonant Solid State Tesla coils]
Laci
December 12, 2019, 08:35:24 PM
post Re: How To Make a Stencil For Spray Paint With Cheap Hand Tools
[General chatting]
johnf
December 12, 2019, 07:53:35 PM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
John123
December 12, 2019, 02:52:58 PM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
John123
December 12, 2019, 02:42:19 PM
post Re: Full bridge much "weaker" than half bridge?
[Solid state Tesla coils]
nick
December 12, 2019, 11:17:36 AM
post Re: Royer oscillator (ZVS) driven Jacob's ladder, E80 core transformer
[Transformer (ferrite core)]
davekni
December 12, 2019, 04:51:08 AM
post Re: Duty cycle when driving a CRT TV flyback transformer
[Transformer (ferrite core)]
davekni
December 12, 2019, 04:26:22 AM
post Re: How To Make a Stencil For Spray Paint With Cheap Hand Tools
[General chatting]
AndreiRS
December 12, 2019, 01:21:35 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