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In the 'good old days of spark transmitters' it was common for rotor or even the rotor and stationary electrodes of tthe rotary gap to be made of cast zinc and I don't remember reading of any health problems or any precautions. Besides , you get a nice blue spark. Ed Futuret wrote: >I've heard that vaporized zinc (from the galvanizing) is >extremely toxic. Whenever I've tried using brass >electrodes they eroded away very quickly. I've had >much better results with copper electrodes. Others >may have had different results, but I thought I'd >mention it. > >John > > > > > > > >-----Original Message----- >From: Greg Peters <greg.j.peters@xxxxxxxxx> >To: Tesla Coil Mailing List <tesla@xxxxxxxxxx> >Sent: Thu, Nov 21, 2013 11:55 pm >Subject: Re: [TCML] DC Coil progress. > > >Thanks everyone for their interest in this project. I will post more >pics of the various components and transformers over the weekend. > >I have some 10mm galvanised steel rod on hand so I will substitute >that until I can find some brass. Hopefully it will perform OK. Sounds >like it will be OK given what Dave said in his post, though I wouldn't >have though the thermal conductivity would be any better than >stainless. > >Ted, thanks for the info. That 6 mot coil of yours must be a real >beast. I've been wanting to build a 3-phase coil since I was a >teenager! I'm hoping to not have to use any filter cap at all given >that I will only be drawing 5-6kW from a supply that could easily do >10. It will be nice to not have to pull 40A from one phase and dim the >neighnours lights! I'm still working the choke thing out. I was >contemplating having a go at winding one myself. Or the series gapped >mots could work too. Still trying to decide which way to go with it. > >Greg, that's a great paper and coil there and I appreciate having some >real DC coil specs on hand. I like your "medium" designation for a >50kW coil! > >I'm happy to try any power supply configuration if you're willing to >advise a suitable topology. I find the one I posted easy to understand >but would need help setting up a delta version. I need a topology that >extracts the full phase to phase voltage, or at least close to it, >given that my transformers are only 2400v. > >I was planning to use 6 MOTs, they have 240v primaries and 2400v >secondaries. We run 240v here in Oz, so I have 415v between phases. I >was going to run two mots per phase with the primaries in parallel and >the secondaries in series. The primaries were going to be run between >active and neutral in a star configuration, as per the image on my >site. This gives 24kV or so in the tank circuit after the choke. >Naturally there is the potential to run the primaries in series >between phases in a delta configuration. Are you able to offer some >advice on how such a configuration should be set up? > >Anyway, I hope all that makes sense. Thanks again everyone for your >advice and interest. > > > > >_______________________________________________ >Tesla mailing list >Tesla@xxxxxxxxxx >http://www.pupman.com/mailman/listinfo/tesla > > > > _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla