Wednesday, October 22, 2014

A Power Beam Tube Tesla coil---First look

 I know it's been a long time since I've posted anything.  That does not mean I have not been doing anything!  This time, after my successful YouTube post of the 200kv Quad Flyback driver powered by my CD-707 (Not yet posted here but can be seen on my YouTube "mostlymacros" channel), I designed a Tesla coil around a large power beam tube.  The top tip is a crossbow bolt on a coffee can as my capacitor.  Features of my oscillator design include a stabilization coil, plate tune and (~I/E) control.

 I kept the plate voltage, provided by a high current/voltage supply I built--to about 1000 volts for these tests as I did not want to damage the camera I was using.  The coil can create sprites as high as about 5 inches or more.  Making it capable of over 120,000 volts with full arc load across secondary.
Tesla coils produce very powerful EM fields.  This one operates at about 300khz (300kc) and operates as high as 1500 volts at about 1amp.  I have yet to get a complete reading however since I must build a meter capable of handling the RF produced as well as the high voltages used.  Newer digital meters have pathetically low voltage levels.  I have only one cat. III meter/scope as can be seen in the YouTube Video--and it's too expensive to risk here!

 Here is my video of the project, click here to view.  Coil is not at full power yet and not complete, I will create another video when it is and upload. 
I hand wound this coil entirely myself, as well as designed the circuits that drive it. You will not find the schematic for this online until I put it up there.  However, there are quite a few VTTC/SSTC schematics online, almost none of which I have tested as I often do my own schematics.  I designed it around a large power beam tube that was probably used for the bigger color TV sets back in the 1960s-70s.   I also came up with an idea for isolation of primary from secondary issues using a large plastic beaker.  Consequentially--I am able to run the coil with far more power and even replace or swap out the HV secondary!  Really useful for testing.  My schematic for this circuit is available on request (email me if interested). I only have a hand drawn version for now in my notebook. I will eventually draw it on CAD software, as I have done other projects on here.  Be sure and watch the YouTube video.  I know it turned out unexpectedly dark--sorry about that--next time I need to use the better camera!  It looked great on my camera in playback. I usually use a relatively inexpensive camera for most of these videos/pics since I don't want to fry my high end one.

I don't like to get my good cameras too close to projects like this!  Any kind of Tesla coil produces very powerful EM/RF fields and can produce several 1000 volts in devices near by so watch things like remote controls, cameras, laptops and memory cards. A metallic and thus somewhat shielded cameras is best. It is not complete yet, When I get the diodes for it's power supply (coming in the mail)-- it will be a self-powered unit that plugs right into any wall outlet.  It can run on 120volts but requires a lot of power, as much as 6 amps in high settings on the 120volt side of things.  About half what a regular microwave oven needs or so.  Since it is an oscillator working with the feedback principle it produces a large amount of tuned RF at about 300khz, so you don't want to hook any long wires to VTTC/SSTC projects as they may create serious radio interference on nav. beakons and or other radio devices.  Some filtration of the AC 120 volt side and/or HV AC side can help keep this RFI to a minimum.  Thanks for checking out my site--Please subscribe if interested--I have been busy and will try to post more often.  I have a backlog of cards to upload, about a half dozen videos and 100s of pics.  So keep comming back!  Thanks--G.Beasley KF7DFP

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