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5' secondary coil safety concerns

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Chip Fixes

Sat Jul 20 2013, 12:49AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

So I'm building a 5' tall secondary coil that I plan to use with my Slayer Exciter circuit

(it may become an awesome Tesla Coil later on)

Here are the specs:
Radius: 6"
Height: 60"
Wire AWG: 26
Turns: ~3,790
Inductance: 780mh
Capacitance: ~23.5pf (Without topload)
Frequency: ~37,174hz

Using the general equation Np/NS = Vp/Vs and subsituting in values Np = 10 turns, Ns = 4,000, I get the equation Vs = 400(Vp), where Vs is the output voltage on the secondary and Vp is the input voltage.
so at 5v the output will be somewhere around 2kv... But I have some beefy transistors and plenty of diodes so what If I rectified a Microwave Oven Transformer? The output on the secondary would be somewhere around 1 megavolt....
What safety precautions should I have in place? Obviously I'll need to stay the f**k away from it and will probably need a strike bar above the primary winding, but is there anything else I should do?

EDIT: Would a Quikrete tube be okay to wind the wire around?

HV Enthusiast

Sat Jul 20 2013, 01:20PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

That slayer exciter circuit is for use with very small secondary coils, as shown in the example. That circuit is just a single transistor SSTC circuit.

You are better of using that secondary for a very large DRSSTC. You won't get anywhere near 1 Megavolt using that Slayer Circuit with a 5 Ft. secondary coil. I'm doubtful you'd get any arc output at all honestly with that circuit and a 5 foot secondary.

If you want to produce some serious voltage and big arcs, forget the slayer exciter circuit you referenced. You need to build a DRSSTC.

Also, Quikrete tubes do work, although the tolerances on those things is pretty poor and the surface is really rough as well which can be a problem is you plan on using very thin magnet wire.

If you only need 6" DIA, then go with a 6" PVC tube. Much better surface for winding.

Dr. Dark Current

Sun Jul 21 2013, 09:17AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

With a slayer exciter circuit, you don't need to take any precautions.

Chip Fixes

Tue Jul 23 2013, 05:34PM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

Alright thanks guys. I was really planning on 12" diameter but I don't think they sell 6' sections of pvc pipe in that size for under $50 in Wisconsin.

Feathers

Tue Jul 23 2013, 10:58PM

Registered Member #10052 Joined: Thu Feb 07 2013, 11:31PM
Location: Overland Park, Kansas
Posts: 78

I found 6' PVC at my hardware store. Others have found some at the home depot and lowes (it was the green drainage stuff). Even the thin stuff stiffens up well with a beefy set of end caps.

Chip Fixes

Wed Jul 24 2013, 04:00AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

Alright I'll call around tomorrow, thanks! I also found a couple posts on Craigslist

HV Enthusiast

Wed Jul 24 2013, 12:56PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Chip Fixes wrote ...

Alright thanks guys. I was really planning on 12" diameter but I don't think they sell 6' sections of pvc pipe in that size for under $50 in Wisconsin.

For greater than 6", you can use the sonotube concrete forms that are available at your local Lowes or Home Depot.
You can also check online for high power rocketry suppliers that may supply both fiberglass and cardboard tubes of 8, 10, and 12" in diameter, although they may be a bit pricey.

Chip Fixes

Mon Jul 29 2013, 07:49AM

Registered Member #3781 Joined: Sat Mar 26 2011, 02:25AM
Location:
Posts: 701

While waiting to get PVC pipe for the 5' coil, I wound and epoxied (first time with epoxy) a 440khz 2' by 3.5" coil. I also was messing around and found out I could play music through the corona by wiring the headphone jack on a radio to the base pin of the transistor. Theres no topload and I'm only sending 30v through the coil so the arc is really small and the music is pretty quiet but here's a video:

My good friend is coming over tomorrow and we'll be adding a top load and may turn it into an SGTC so I will post more tomorrow night.

EDIT: the touch screen on my phone is useless while the SE is running, which is why I started the video with the phone away from the coil haha

SECOND EDIT: I want to be able to connect my computer or ipod to the coil at some point later on but I am afraid all the reverse emf will screw things up. Can anyone link me a schem or give me some advice as to how to protect the audio source from that? Thanks!

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