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Re: [TCML] Questions on grounding



I agree with all of the above. It's been a while since I built an NST coil but when I did last, I created a nice earth ground by digging a 5 foot wide by 3 or so foot deep hole and burying a few turns of copper tubing in it. I just grounded my NST to house ground thinking it was good to keep them separate. No real science to support using separate paths but the coil performed well. It was a 4 inch coil using a couple roof flashing caps I built and a static gap. Don't recall the exact performance details but I want to say sparks in the 3-4ft range were pretty common using a 12in aluminum tap toroid. 

I remember reading somewhere that if you have to fall short on your coil somewhere, the base ground is the last place to do it...


________________________________
From: bartb <bartb@xxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Tuesday, April 14, 2009 8:53:52 PM
Subject: Re: [TCML] Questions on grounding

Jay (and Joe),

You do need a dedicated ground separate to your house ground of which your bottom secondary should certainly be tied to. With the NST, you can either connect the case to house ground or to this dedicated RF ground. But, realize that if you connect the case to house ground, the "house" components will have nasty RF spikes and transients running directly to all of your appliances in the house. If you tie the NST case to RF ground and end the house ground back at the control cabinet, you will have far less electrical mess at your appliances. The choice is yours.

Anyone stating to "never connect the NST to the secondary RF ground" I strongly disagree with. Look in the TCML archives as there are plenty of discussions regarding this very issue which we've discussed many (many) times (only a month ago I believe was the last blurb).

Take care,
Bart

jhowson4@xxxxxxxxxxx wrote:
> First of all I am thinking that you need to connect the bottom of your secondary NOT to your NST. you need a separate ground for called the RF ground for the secondary. 
> The case and ground of the NST should be connected to your house ground and never connected to your secondary. 
> making the toroid really smooth will increase spark length. I have found that covering the tubing with plaster, sanding it smooth then covering it with aluminum duct tape, and smoothing that over with a spoon works really well. it is also beneficial to fill the interior of the tubing with some expanding foam to help prevent it from being crushed so easily. Here is a pic of my coil with the closest pic of the top load that I had. http://i139.photobucket.com/albums/q295/JHowson/DSC06682.jpg 
> Jay Howson 
> ----- Original Message ----- From: "jocatch" <jocatch@xxxxxxxxxxx> To: tesla@xxxxxxxxxx Sent: Tuesday, April 14, 2009 9:35:05 AM GMT -05:00 US/Canada Eastern Subject: [TCML] Questions on grounding 
> Hello. I have built my first coil using standard parts and dimensions and have fired it up and so far I am producing sparks but only about 12" long. I am using a 12KV nst with .0125uf mmf, 13 turns of copper tubing as primary and 20" of #28 magnet wire on a 4" form with aluminum cloths dryer ducting for the toroid 
> My questions concerning grounding. I have read alot about discharge spark length but not much regarding how to measure it. Above I said 12" discharge spark length, that was to a key ring held at the end of a boom stick handle. Should the metal object that I am drawing the spark to be grounded? To earth ground? Right now nothing is grounded to earth or electrical ground. The bottom side of the secondary coil is connected to the metal case of the nst. Should the secondary coil and nst be grounded to earth ground? 
> Lastly, the aluminum toroid is discharging all around its circumference. I know the fewer discharge points on the top load, the bigger the discharge length will be. If I tape the toroid with aluminum tape to produce a smoother surface, will it help? 
> I have a web page showing photos of my first tesla coil before I recently updated it to copper tubing and new toriod. The web page shows the old primary wire coil and old topload. I will post new pictures of the update soon. 
> http://www.joecool.org/joe_s_tesla_coil.htm 
> Thanks for your help. 
> joe _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxxxxxx://www.pupman.com/mailman/listinfo/tesla _______________________________________________
> Tesla mailing list
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