[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[TCML] A Safe Tesla Coil - was: Tesladownunder update, briefcase coil, lots of sparks etc



Peter,
I'm sure from the construction pictures of your coil that a dangerous failure is unlikely and ensuring the subject is holding an earthed neon is a good way of minimising the risk.

I have been searching a way of making a "safe" tesla coil for a while from the point of 'the sparks can't kill you' . I know about RF heating, skin effect an the other associated dangers of high voltage RF. I know it can't ever be totally safe, but if you are using a coil as a demonstration piece the possibility always remains that you or a subject will come in contact with an arc.

So far my attempts a making a safe coil have resorted to designing them battery powered to eliminate the danger of mains connecting to arc by whatever means.

I too have been skeptical about the primary-secondary arc increasing the arc current. I have always used the possibility as a worst case scenario when thinking about coil safety. I had wondered if the Henry Transtrom case was caused by a faulty secondary earth which would make more sense than purely a secondary-primary strike in a solidly constructed TC. Maybe one of the historians in TCML could shed some light on this.

I'm not too sure I would trust PVC pipe either as a good insulator at TC frequencies, I have a number of small coils with PVC primary formers burning through or around to the secondary.

Maybe an earthed spiral metal shield between primary and secondary would help to remove the possibility of primary-secondary arc over/through.

   Cheers
      Derek

Peter Terren wrote:
Hi Derek
Firstly, mains earth is the RF earth and goes to all the metal in the briefcase which is the centrepoise. Secondly, spark length is such that it is just not going to connect through the PVC pipe surround separating the primary and secondary. The primary is fully enclosed. Child use means the child holding a small neon tube that is earthed and drawing sparks. It is hard to imagine a circuit path that will be a problem in this situation. I have always been a little skeptical about the situation you describe anyway. Simultaneous sparks from primary to seconday plus toroid to subject seem a bit far fetched. The circuit path for a mains = RF earth would be very largely in favour of flow through the base of the secondary rather than through the subject. Do you (or anyone) have reasonable evidence that this has increased secondary current and if so why aren't we exploiting this all the time to increase our TC sparks? I am aware the Henry Transtrom was said to have been killed in this way but I would have thought it was just a high power coil that was the problem.

Cheers
Peter
www.tesladownunder.com


----- Original Message ----- From: "Derek" <tesla@xxxxxxxxxxxxxxxxxxxxxxxx>


Peter,
..... I am interested as to how you have made this coil safe "for supervised children to use". I realise that the power levels and performance mean that the risk of electrocution directly are very small, but to my mind the most dangerous aspect of you coil is the possibility of a primary to secondary arc whilst a "tasting" was in progress. In this case there is a very real danger of connecting the 6Kv@30mA output from the NST via the secondary and arc channel to the "taster".

Have you designed the coil in a way to limit or prevent this possibility ?

   Derek

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla

_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla