Correctely ground a TC
Unleashed, Thu Jul 12 2012, 04:06PMHello everyone.
Sorry if i'm opening so many threads so far, but since it's my first TC, i really need to know lot of things, so please be patient :)
My question today is
How to correctely ground my tc?
I mean, my home power plant, has no ground, so i can't do it by just setting it on the middle pin of the socket.
What i wanted to do, is grounding it by planting a steel bar( like one of those
) in the ground, and maybe give it some salt water.But someone told me that at high frequencies some material becomes bad conductors.
So, how should i ground my TC?
Thanks.
Re: Correctely ground a TC
Tetris, Thu Jul 12 2012, 05:22PM
I use a copper pipe, about 5 feet in length, 4 feet I was able to bury into the ground. If it hasn't rained in a while (saying you live in Italy, in a Mediterranean climate, drought should hardly be a problem), say, a week or so, then I suggest watering it with a simple garden hose. :D hope that helps.
Tetris, Thu Jul 12 2012, 05:22PM
I use a copper pipe, about 5 feet in length, 4 feet I was able to bury into the ground. If it hasn't rained in a while (saying you live in Italy, in a Mediterranean climate, drought should hardly be a problem), say, a week or so, then I suggest watering it with a simple garden hose. :D hope that helps.
Re: Correctely ground a TC
Patrick, Thu Jul 12 2012, 06:48PM
At high frequency the cross section of the conductor starts to effectively shrink, due to skin effect. And the conductor acts as if it were a hollow pipe at HF, (even if its a solid rod). But i think for TC use as highvoltagechick said, use a copper water pipe, it seems to work for many people just fine.
Patrick, Thu Jul 12 2012, 06:48PM
At high frequency the cross section of the conductor starts to effectively shrink, due to skin effect. And the conductor acts as if it were a hollow pipe at HF, (even if its a solid rod). But i think for TC use as highvoltagechick said, use a copper water pipe, it seems to work for many people just fine.
Re: Correctely ground a TC
Unleashed, Thu Jul 12 2012, 07:46PM
I have bought a 1.5meters grounding rod.
But.. it'll be hard to plant it in the ground :P It's like 40°C and doesn't rain since a month or so...
Unleashed, Thu Jul 12 2012, 07:46PM
I have bought a 1.5meters grounding rod.
But.. it'll be hard to plant it in the ground :P It's like 40°C and doesn't rain since a month or so...
Re: Correctely ground a TC
Patrick, Thu Jul 12 2012, 08:02PM
start pounding.... some electricians use a tiny jack hammer-like device thats meant to drive the longer rods in.
Patrick, Thu Jul 12 2012, 08:02PM
start pounding.... some electricians use a tiny jack hammer-like device thats meant to drive the longer rods in.
Re: Correctely ground a TC
Dr. Slack, Fri Jul 13 2012, 07:13AM
Sigh, I see so much BS talked about coil grounding.
Why do you want to ground your coil? Electrical safety, like able to blow supply fuses in the event of short circuit, or RF performance?
If you want RF performance, which includes reducing emissions to to other parts of the house, then you need something approximating to an RF ground plane *immediately below the coil*, connected to the bottom of the secondary. An RF ground plane could be a large sheet of solid metal, or large sheet of chicken wire, or several straight wires fanning out in a radial fashion from the middle. If you are running it in a field, put a wire down from the bottom of the secondary to a teaspoon or tent-peg stuck in the ground. The currents are so low, the impedance so high, that that is enough.
If you want safety, then additionally you connect the earthy bits in your primary circuit back to mains ground. If mains ground is not available, then you pound a 6ft pole into wet ground, and/or put croc-clips to all the metal pipes that you have buried in the ground. The currents required are so high, the impedance so low, that you need all the help you can get.
Neither grounding system depends on the other. Neither grounding system will do the job of the other.
Dr. Slack, Fri Jul 13 2012, 07:13AM
Sigh, I see so much BS talked about coil grounding.
Why do you want to ground your coil? Electrical safety, like able to blow supply fuses in the event of short circuit, or RF performance?
If you want RF performance, which includes reducing emissions to to other parts of the house, then you need something approximating to an RF ground plane *immediately below the coil*, connected to the bottom of the secondary. An RF ground plane could be a large sheet of solid metal, or large sheet of chicken wire, or several straight wires fanning out in a radial fashion from the middle. If you are running it in a field, put a wire down from the bottom of the secondary to a teaspoon or tent-peg stuck in the ground. The currents are so low, the impedance so high, that that is enough.
If you want safety, then additionally you connect the earthy bits in your primary circuit back to mains ground. If mains ground is not available, then you pound a 6ft pole into wet ground, and/or put croc-clips to all the metal pipes that you have buried in the ground. The currents required are so high, the impedance so low, that you need all the help you can get.
Neither grounding system depends on the other. Neither grounding system will do the job of the other.
Re: Correctely ground a TC
brandon3055, Fri Jul 13 2012, 08:16AM
For my.latest tc build I use manes ground for safety and for the rf ground I just have a wire from my secondary to my shed and it seems to work ok what is you opinion on this method
brandon3055, Fri Jul 13 2012, 08:16AM
For my.latest tc build I use manes ground for safety and for the rf ground I just have a wire from my secondary to my shed and it seems to work ok what is you opinion on this method
Re: Correctely ground a TC
Dr. Dark Current, Fri Jul 13 2012, 09:57AM
I have ran coils with sparks up to 60cm (24") grounded to mains ground. Put some caps a few tens of nF from live and neutral to Earth.
Dr. Dark Current, Fri Jul 13 2012, 09:57AM
I have ran coils with sparks up to 60cm (24") grounded to mains ground. Put some caps a few tens of nF from live and neutral to Earth.
Re: Correctely ground a TC
Sigurthr, Fri Jul 13 2012, 11:38AM
Being a Ham I fully agree and understand the importance of a proper ground plane grounding system when dealing with most RF sources, but I have a practical question for you: How do you stop the ground plane from sapping energy out of the system due to induced eddy currents from the Primary's magnetic field? I tried a similar setup using a large sheet of steel under the coil and got zero output from the secondary and the ground plane got VERY hot very fast. I tried increasing the vertical distance between the tesla resonator and the ground plane but could not achieve a set up where the ground plane was not badly drawing energy from the coil, even if heating was reduced below perceivable levels.
From my experience a ground plane is good in theory for a TC but bad in practice.
Sigurthr, Fri Jul 13 2012, 11:38AM
Dr. Slack wrote ...
Sigh, I see so much BS talked about coil grounding.
Why do you want to ground your coil? Electrical safety, like able to blow supply fuses in the event of short circuit, or RF performance?
If you want RF performance, which includes reducing emissions to to other parts of the house, then you need something approximating to an RF ground plane *immediately below the coil*, connected to the bottom of the secondary.
Sigh, I see so much BS talked about coil grounding.
Why do you want to ground your coil? Electrical safety, like able to blow supply fuses in the event of short circuit, or RF performance?
If you want RF performance, which includes reducing emissions to to other parts of the house, then you need something approximating to an RF ground plane *immediately below the coil*, connected to the bottom of the secondary.
Being a Ham I fully agree and understand the importance of a proper ground plane grounding system when dealing with most RF sources, but I have a practical question for you: How do you stop the ground plane from sapping energy out of the system due to induced eddy currents from the Primary's magnetic field? I tried a similar setup using a large sheet of steel under the coil and got zero output from the secondary and the ground plane got VERY hot very fast. I tried increasing the vertical distance between the tesla resonator and the ground plane but could not achieve a set up where the ground plane was not badly drawing energy from the coil, even if heating was reduced below perceivable levels.
From my experience a ground plane is good in theory for a TC but bad in practice.
Re: Correctely ground a TC
Dr. Dark Current, Fri Jul 13 2012, 12:11PM
I think the frequencies of normal TCs are so low (few hundred kHz), that a ground plane is not necessary.
Dr. Dark Current, Fri Jul 13 2012, 12:11PM
I think the frequencies of normal TCs are so low (few hundred kHz), that a ground plane is not necessary.
Re: Correctely ground a TC
Unleashed, Fri Jul 13 2012, 01:42PM
Thanks for the answer.
What i'm going to do, it's connect the logic part metal box to ground, together with the down lead of the secondary (that's what the project says).
But since i'm going to run this TC on the third floor of my home, can i run a 9-10meters cable from the TC to the ground without problems?
Unleashed, Fri Jul 13 2012, 01:42PM
Thanks for the answer.
What i'm going to do, it's connect the logic part metal box to ground, together with the down lead of the secondary (that's what the project says).
But since i'm going to run this TC on the third floor of my home, can i run a 9-10meters cable from the TC to the ground without problems?
Re: Correctely ground a TC
Dr. Slack, Fri Jul 13 2012, 02:58PM
Well, yes you can. But why? Just because you can do something without problems, for instance recite a valedictory before disposing of any durable product, doesn't mean it will acheive anything, or that you should.
A TC has very high voltage AC on that terminal thing on the top, which induces a voltage in everything that has a non-zero capacitance with it, from which a current will flow according to its impedance back to the bottom terminal of the secondary.
If you are on the third floor, then the most useful thing you can do is to run several ground radials out from the bottom of your TC, to the earth pin of each mains socket in the room, to each bit of exposed water pipe, balcony railings, set of metal shelves etc. Failing that, one wire to one socket will still be better than 10m out of the window down to yard.
OK, most people don't do that. They use one connection to the mains earth, or via a long wire to a remote bit of dirt. I do what I recommend, as it minimises the interference to other stuff in my house, and in the neighbours'. Basically it tries to complete as much of a Faraday cage around the TC and connected to the secondary bottom terminal, without physically going to the bother of building one, just using the conductivity of all the stuff that is around it. If you connect one wire to one socket, you are energising the random antenna that is your house wiring more strongly than if you recruit all the conductors in the room. A lot of people get away with that. If you drop 10m of wire out of the window, you are making a nice long inductor/antenna.
Calling it ground doesn't make it ground.
Dr. Slack, Fri Jul 13 2012, 02:58PM
Unleashed wrote ...
But since i'm going to run this TC on the third floor of my home, can i run a 9-10meters cable from the TC to the ground without problems?
But since i'm going to run this TC on the third floor of my home, can i run a 9-10meters cable from the TC to the ground without problems?
Well, yes you can. But why? Just because you can do something without problems, for instance recite a valedictory before disposing of any durable product, doesn't mean it will acheive anything, or that you should.
A TC has very high voltage AC on that terminal thing on the top, which induces a voltage in everything that has a non-zero capacitance with it, from which a current will flow according to its impedance back to the bottom terminal of the secondary.
If you are on the third floor, then the most useful thing you can do is to run several ground radials out from the bottom of your TC, to the earth pin of each mains socket in the room, to each bit of exposed water pipe, balcony railings, set of metal shelves etc. Failing that, one wire to one socket will still be better than 10m out of the window down to yard.
OK, most people don't do that. They use one connection to the mains earth, or via a long wire to a remote bit of dirt. I do what I recommend, as it minimises the interference to other stuff in my house, and in the neighbours'. Basically it tries to complete as much of a Faraday cage around the TC and connected to the secondary bottom terminal, without physically going to the bother of building one, just using the conductivity of all the stuff that is around it. If you connect one wire to one socket, you are energising the random antenna that is your house wiring more strongly than if you recruit all the conductors in the room. A lot of people get away with that. If you drop 10m of wire out of the window, you are making a nice long inductor/antenna.
Calling it ground doesn't make it ground.
Re: Correctely ground a TC
Mattski, Fri Jul 13 2012, 07:21PM
Mattski, Fri Jul 13 2012, 07:21PM
Sigurthr wrote ...
Being a Ham I fully agree and understand the importance of a proper ground plane grounding system when dealing with most RF sources, but I have a practical question for you: How do you stop the ground plane from sapping energy out of the system due to induced eddy currents from the Primary's magnetic field? I tried a similar setup using a large sheet of steel under the coil and got zero output from the secondary and the ground plane got VERY hot very fast. I tried increasing the vertical distance between the tesla resonator and the ground plane but could not achieve a set up where the ground plane was not badly drawing energy from the coil, even if heating was reduced below perceivable levels.
From my experience a ground plane is good in theory for a TC but bad in practice.
Put slots in your ground plane. If you current is flowing in a circle in your primary the induced eddy currents want to flow in a circle in the opposite direction. Put radial slots to break that current path. It's the same purpose of the laminations in a steel transformer core. You still get the capacitive return path from the top of the secondary to the bottom, which is the purpose of the ground plane.Being a Ham I fully agree and understand the importance of a proper ground plane grounding system when dealing with most RF sources, but I have a practical question for you: How do you stop the ground plane from sapping energy out of the system due to induced eddy currents from the Primary's magnetic field? I tried a similar setup using a large sheet of steel under the coil and got zero output from the secondary and the ground plane got VERY hot very fast. I tried increasing the vertical distance between the tesla resonator and the ground plane but could not achieve a set up where the ground plane was not badly drawing energy from the coil, even if heating was reduced below perceivable levels.
From my experience a ground plane is good in theory for a TC but bad in practice.
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