Indoor Tesla Coil Use / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Indoor Tesla Coil Use

Move Thread

LAN_403

Erik

Thu Sept 06 2007, 12:47AM

Registered Member #982 Joined: Thu Sept 06 2007, 12:32AM
Location: Oakland, CA
Posts: 2

I'm new to tesla coils and don't have a convenient place to run test and debug outdoors. I'd like to build a coil which I can use in my indoor workshop. I have seen many pictures of people running tesla coils indoors. What are people doing for an RF ground? What are some precautions people take to not kill electronics in their house? How bad is it that the arcs strike the walls, ceiling, and floor (also seen in many pictures?)

Thanks,
Erik

Ken M.

Thu Sept 06 2007, 07:03AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

RF grounding, I'd say we all use RFI plugs a little box that has the gnd, hot and neutral pins with some caps and inductors inside, these RFI plugs WON'T stop the RF but it will diminish it. AS for the indoor use I try to stay at least 1 room away from any sensitive electronics, but even that isn't all that safe, I usually run my on the kitchen table and the wall outlet I use Is on its own circuit breaker in the house along with a ceiling light, but the RFI still manages to reach my pc in the next room over and I can here the ESD in the speakers, even though its more of a staticy sound with a click, NEVER use a TC on the same Circuit as any sensitive electronics, the Micro coil that I built (from steve wards design) awhile back was plugged into an outlet on the same circuit as my pc, and My pc would randomly restart if the tc was on, and that was from a small TC.

Hazmatt_(The Underdog)

Thu Sept 06 2007, 08:06AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

It depends on the type of coil and power level.

I can't really comment on any solid state coil, but for spark gap systems Do Not use the house ground to terminate your RF ground in your coil system. What I mean by this is do not connect the strike rail, end of secondary or secondary strike objects to your house ground. You do not want any HV potential on ANY of your wiring. A few KV in your wiring could cause serious problems, destroyed equipment, and for the case of apartment neighbors their equipment as well.

You will have to be aware of what can and what cannot share the house ground, like the ground on the NST, line filter, variac housings, spark gap motor housing, etc. But this has already been discussed a few times and is in the forum if you do a search for it.

Steve Conner

Thu Sept 06 2007, 09:23AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Hi all,

These days I do most of my Tesla coiling with a DRSSTC in a 4th floor apartment full of computers

What I do is to tie the secondary base, strike rails, and any strike targets all together with heavy wire, and call this the RF ground. I connect the RF ground to the ground wire of the electrical service where it enters the apartment. I have seen people use water pipes, but I know that I have sections of plastic pipe somewhere.

All the other grounds (drive electronics, heatsink, etc) are connected to the green wire of the outlet that I'm powering the coil from. I don't use any form of EMI filter or surge protector on the line.

I'm not saying that this is the right way to do it, because grounding is a controversial subject. I'm just saying that it has worked for me so far. I've made 4 foot long ground arcs without even having the DSL modem drop the line, let alone crashing my computer.

I think solid-state coils are more benign from an EMI point of view, though. The streamers from a coil don't seem to generate too much RFI, unless they arc to ground, and even then, it's relatively low frequency stuff. The spark gap in a SGTC generates a lot of RFI at VHF frequencies, and I wouldn't care to try using one in an apartment for fear of trashing my neighbours' TV and radio reception.

thedatastream

Thu Sept 06 2007, 01:00PM

Registered Member #505 Joined: Sun Nov 19 2006, 06:42PM
Location: Yorkshire!
Posts: 329

Steve Conner wrote ...
I think solid-state coils are more benign from an EMI point of view, though. The streamers from a coil don't seem to generate too much RFI, unless they arc to ground, and even then, it's relatively low frequency stuff. The spark gap in a SGTC generates a lot of RFI at VHF frequencies, and I wouldn't care to try using one in an apartment for fear of trashing my neighbours' TV and radio reception.

What about SISGs? They don't have the formation of a spark so presumably they are less "noisy" than their spark gap equivalents?

James

Steve Conner

Thu Sept 06 2007, 01:40PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Yes, I would like to think that a SiSG would be no noisier than a DRSSTC or OLTC.

Dr. Drone

Thu Sept 06 2007, 03:00PM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Finn Hammer

Thu Sept 06 2007, 05:33PM

Registered Member #205 Joined: Sat Feb 18 2006, 11:59AM
Location: SkÃ¸rping, Denmark
Posts: 741

thedatastream wrote ...

What about SISGs? They don't have the formation of a spark so presumably they are less "noisy" than their spark gap equivalents?

James

At present I am having strong hopes in that same direction.

Cheers, Finn Hammer

Terry Fritz

Thu Sept 06 2007, 11:55PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

What about SISGs?

A lot of RF noise is from the very high current/voltage spark gap crushing local capacitively stored energy near the electrodes through very low inductances. This causes powerful RF noise well into the GHz range. The SISG has a far more gentle turn-on and the energies are lower since there is a long low voltage string instead of a high voltage single point area (e = 1/2 x C x V^2). The SISG is also fairly isolated from the AC line and such as a conductor of RF noise. So, in general, the SISG primary system is far quieter than a fire breathing conventional gap. Of course, the output arcs are electrically noisy especially if conducted directly to ground (a good thing).

So there is still enough noise there to mess with near radio and broadcast TV, but the magnitude is pretty safe for nearby electrical equipment as long as the grounding is well considered.

Cheers,
Terry

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob