Small SGTC.
Duncan, Thu Feb 15 2007, 03:51AMA few months ago I started making some rough plans for a new small spark gap coil, as I felt I had been deprived long enough
What I wanted to achieve was a small, lightweight and reliable coil that I can pull out every now and again for a run. I wanted it to be as hassle-free to set up as possible, and should need very low maintenance. I also wanted it to look nice and neat (so other family members wouldn't make me keep it out in the shed). My starting point was a 7.5kV 25mA NST I bought off the net, and a couple of wooden chopping boards from the local supermarket 
I've been saving these little updates for a while, so here they are:
Cut the handles off two wooden chopping boards and rounded the edges to make it look like the handles were never there (which took ages). I cut some pine doweling into 125mm lengths and drilled some countersunk holes in the boards and screwed everything together with heavy duty galvanised screws, and it is as solid as a rock. It turned out to be heavier than I thought it would be, but that's no problem.
Here's a couple of pics (they're a bit dodgy, but you get the idea). Theres a bit of lens distortion which makes the back left doweling support look crooked, but it really isn't.
Duncan.
Re: Small SGTC.
Duncan, Thu Feb 15 2007, 03:55AM
The perspex arrived and I've drilled a 60mm hole in it and another one on top of the frame (so thay they'll line up when the perspex is placed on top of the frame.) The hole is for the secondary coil to go through so it will be able to sit nice and solid in the frame, and can also be removed easily if need be. I've also cut the PVC for the secondary coil, and spent about 2 hours winding the 0.2mm copper wire. There are approximately 1040 turns in total. Here are a few pics:
Duncan.
Duncan, Thu Feb 15 2007, 03:55AM
The perspex arrived and I've drilled a 60mm hole in it and another one on top of the frame (so thay they'll line up when the perspex is placed on top of the frame.) The hole is for the secondary coil to go through so it will be able to sit nice and solid in the frame, and can also be removed easily if need be. I've also cut the PVC for the secondary coil, and spent about 2 hours winding the 0.2mm copper wire. There are approximately 1040 turns in total. Here are a few pics:
Duncan.
Re: Small SGTC.
Duncan, Thu Feb 15 2007, 03:59AM
Finally got around to finishing most of the capacitor bank. Here are a few pics:
Duncan.
Duncan, Thu Feb 15 2007, 03:59AM
Finally got around to finishing most of the capacitor bank. Here are a few pics:
Duncan.
Re: Small SGTC.
Duncan, Thu Feb 15 2007, 04:01AM
Finished soldering all the bleeder resistors onto the caps. The cap bank is finished now.
Duncan.
Duncan, Thu Feb 15 2007, 04:01AM
Finished soldering all the bleeder resistors onto the caps. The cap bank is finished now.
Duncan.
Re: Small SGTC.
Hazmatt_(The Underdog), Thu Feb 15 2007, 06:27AM
Use the Attachments thread to add pictures, then you can post all your pictures at a later time in the same thread. Otherwise, good job!
Hazmatt_(The Underdog), Thu Feb 15 2007, 06:27AM
Use the Attachments thread to add pictures, then you can post all your pictures at a later time in the same thread. Otherwise, good job!
Re: Small SGTC.
uzzors2k, Thu Feb 15 2007, 08:58AM
Wow, thats clean. Looks good.
uzzors2k, Thu Feb 15 2007, 08:58AM
Wow, thats clean. Looks good.
Re: Small SGTC.
Duncan, Thu Feb 15 2007, 09:10AM
Duncan.
Duncan, Thu Feb 15 2007, 09:10AM
Hazmatt_(The Underdog) wrote ...
Use the Attachments thread to add pictures, then you can post all your pictures at a later time in the same thread. Otherwise, good job!
Thanks Hazmatt, I've updated my original posts with proper linked thumbnail pics.Use the Attachments thread to add pictures, then you can post all your pictures at a later time in the same thread. Otherwise, good job!
uzzors wrote ...
Wow, thats clean. Looks good.
Thanks uzzors. Yeah the thing I'm trying to do with this coil is make it as nicely made as possible so a) I'll be allowed to keep it in the house, and b) Will hopefully be something cool to look at when it is and isn't powered up.Wow, thats clean. Looks good.
Duncan.
Re: Small SGTC.
Duncan, Fri Apr 13 2007, 01:54PM
OK, I've finally gotten around to wiring everything up and giving it a test run. It appears to work well, with streamer length between 30 and 40cm. It does appear that I'll need a toroidal topload, as the spherical one is a bit lacking in terms of shielding. Anyway, here's a couple of pics and a link to a video taken shortly after first light.
And a short video:
Duncan.
Duncan, Fri Apr 13 2007, 01:54PM
OK, I've finally gotten around to wiring everything up and giving it a test run. It appears to work well, with streamer length between 30 and 40cm. It does appear that I'll need a toroidal topload, as the spherical one is a bit lacking in terms of shielding. Anyway, here's a couple of pics and a link to a video taken shortly after first light.
And a short video:
Duncan.
Re: Small SGTC.
Hazmatt_(The Underdog), Sat Apr 14 2007, 02:35AM
Nicely done.
Hazmatt_(The Underdog), Sat Apr 14 2007, 02:35AM
Nicely done.
Re: Small SGTC.
Coronafix, Sun Apr 15 2007, 12:42AM
Beautifully neat and effective coil Duncan. Can you give
us some specifications on it? What's the transformer rating?
Coronafix, Sun Apr 15 2007, 12:42AM
Beautifully neat and effective coil Duncan.
Can you give us some specifications on it? What's the transformer rating?
Re: Small SGTC.
Duncan, Mon Apr 16 2007, 02:48AM
Oh yeah, how could I forget to provide the specs
The NST is 7.5kV 25mA, cap bank is two parallel strings of nine 0.047uF 1500V polypropylene axial caps (each with its own 0.5W 10M metal film resistor). The secondary is 60mm diameter PVC wound for 9" with 0.2mm magnet wire (I think that's 32G). The primary is 12 turns of 8G OFC, with tapping points cut in the insulation every half turn. The topload is a 10cm stainless steel candle holder I found at the local hardware shop
Duncan.
Duncan, Mon Apr 16 2007, 02:48AM
Oh yeah, how could I forget to provide the specs
The NST is 7.5kV 25mA, cap bank is two parallel strings of nine 0.047uF 1500V polypropylene axial caps (each with its own 0.5W 10M metal film resistor). The secondary is 60mm diameter PVC wound for 9" with 0.2mm magnet wire (I think that's 32G). The primary is 12 turns of 8G OFC, with tapping points cut in the insulation every half turn. The topload is a 10cm stainless steel candle holder I found at the local hardware shop Duncan.
Re: Small SGTC.
vasil, Mon Apr 16 2007, 08:12AM
Very nice looking project Duncan! Congratulations!
vasil, Mon Apr 16 2007, 08:12AM
Very nice looking project Duncan! Congratulations!
Re: Small SGTC.
Sulaiman, Mon Apr 16 2007, 09:22AM
Yes, nice job, well done.
I'm inspired to make a small SGTC myself
(possibly in time for the new millenium due to severe poly-projectitis)
Sulaiman, Mon Apr 16 2007, 09:22AM
Yes, nice job, well done.
I'm inspired to make a small SGTC myself
(possibly in time for the new millenium due to severe poly-projectitis)
Re: Small SGTC.
Marko, Mon Apr 16 2007, 11:27AM
Very beautiful, and looks efficient as well for that small NST!
Have you considered upgrading your SG to a multigap? 16inch sparks are still great considering 22 inch maximum for your transformer.
Marko, Mon Apr 16 2007, 11:27AM
Very beautiful, and looks efficient as well for that small NST!
Have you considered upgrading your SG to a multigap? 16inch sparks are still great considering 22 inch maximum for your transformer.
Re: Small SGTC.
Duncan, Mon Apr 16 2007, 03:13PM
I have considered a multigap yeah, that will be a project for next holidays I'll also look into getting myself a proper spun toroid from somewhere, as the sphere isn't all that great. However, I have added a more stylish breakout point to the spherical topload today to help keep the streamers 'under control'. Makes it look a bit evil also I think
Duncan.
Duncan, Mon Apr 16 2007, 03:13PM
I have considered a multigap yeah, that will be a project for next holidays
I'll also look into getting myself a proper spun toroid from somewhere, as the sphere isn't all that great. However, I have added a more stylish breakout point to the spherical topload today to help keep the streamers 'under control'. Makes it look a bit evil also I think 
Duncan.
Re: Small SGTC.
Vaxian, Wed Apr 18 2007, 05:31AM
Yes, congrats, Very cool looking coil.
The boss should let you display it in the living room!
My boss has banned me to the garage, which is OK, there's more room out there anyways!
Vaxian, Wed Apr 18 2007, 05:31AM
Yes, congrats, Very cool looking coil.
The boss should let you display it in the living room!
My boss has banned me to the garage, which is OK, there's more room out there anyways!
Re: Small SGTC.
Dalus, Wed Apr 25 2007, 08:16PM
Damn nice coil. I wish that my coils would look as nice as yours.
Dalus, Wed Apr 25 2007, 08:16PM
Damn nice coil. I wish that my coils would look as nice as yours.
Re: Small SGTC.
Duncan, Thu Apr 26 2007, 09:10AM
Heh, it's not something you need to wish for, just spend a lot of time working on it carefully
Duncan.
Duncan, Thu Apr 26 2007, 09:10AM
Heh, it's not something you need to wish for, just spend a lot of time working on it carefully
Duncan.
Re: Small SGTC.
Dalus, Thu Apr 26 2007, 11:35AM
That's exactly what I'm going to do with my drsstc-2. The rest of my coils are build as test-beds. Hopefully I'll get the parts for my drsstc soon, I've been waiting for 0.5 years now. Damn digikey
Dalus, Thu Apr 26 2007, 11:35AM
That's exactly what I'm going to do with my drsstc-2. The rest of my coils are build as test-beds. Hopefully I'll get the parts for my drsstc soon, I've been waiting for 0.5 years now. Damn digikey
Re: Small SGTC.
Andrew L., Thu Apr 26 2007, 04:20PM
Duncan when are e going ot see the coil in operation?
Andrew L., Thu Apr 26 2007, 04:20PM
Duncan when are e going ot see the coil in operation?
Re: Small SGTC.
Duncan, Fri Apr 27 2007, 07:15AM
Duncan, Fri Apr 27 2007, 07:15AM
Andrew L. wrote ...
Duncan when are e going ot see the coil in operation?
I linked a video of it in one of my previous posts Duncan when are e going ot see the coil in operation?
Print this page