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RSG -- rotary spark gap

Subject: 
        RSG -- rotary spark gap
  Date: 
        Fri, 28 Mar 1997 10:06:08 -0700
  From: 
        "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
    To: 
        "Tesla List" <tesla-at-pupman-dot-com>


A 5/8 inch thick G-10 glass laminate makes a good rotor disc.  For 5-15
KVA
systems use a 1725 RPM 3/4 HP motor equipped with 10 electrodes on a 12
in.
dia. disk.  3450 RPM seems to overquench.  We use 1/2 dia. brass thru
holes
that have been precision reamed .001 oversize and brass is press fit
with a
small press.  The brass is 1 1/2 inches long and each end fitted with a
standard tungsten-molydenum screw in electrode.  They seem to last about
7
years in rotary service.  We use a 1 inch dia. screw in electrode for
the 4
fixed electrodes and replace them once every 3 years (that assumes
museum
is doing 3 presentations a day x 6 days per week).  They are a little
expensive but in experimenter service should last about 40 years or so!!

Type LE and CE phenolic (carmel colored) seems to soften slightly so
safety
becomes an issue with these materials. Never try to build the rotor
yourself --- always have a machine shop do it so absolute precision is
maintained -- never mind expense either -- how much is an eye worth??? 
A
machine shop should balance the rotor to 5000 RPM.  Again cost enter the
picture but these rotors can be dangerous so safety has to become a
strong
concern.  We have been making our rotors this way for over 20 years
without
ever having a single rotor explosion (knock on wood). 

DR.RESONANCE-at-next-wave-dot-net

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-poodle.pupman-dot-com
> Subject: RE: A "Revolutionary" Idea
> Date: Wednesday,March 26,1997 9:45 PM
> 
> Subject: 
>             RE: A "Revolutionary" Idea
>        Date: 
>             Thu, 27 Mar 1997 07:50:38 +1200
>        From: 
>             "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
> Organization: 
>             Wellington Polytechnic, NZ
>          To: 
>             tesla-at-pupman-dot-com
> 
> 
> Hi William, all,
>                    Commenting on more revolutionary ideas....
> 
> >   From: 
> >         "William Noble" <William_B_Noble-at-msn-dot-com>
> >     To: 
> >         "Tesla List" <tesla-at-pupman-dot-com>
> > 
> > 
> > why not spin a notched ceramic disk, so the insulator moves and the gap
> > stays 
> > fixed???  actually, a saphire disk would not be too expensive either,
or
> > pyrex 
> > - put holes in it (maybe better than notches due to stress build up) -
> > when 
> > the hole aligns with a gap, it can spark, once it passes, it cannot. 
> > And, the 
> > spinning disk would still create a good wind to cool and quench.
> 
> It is an idea I like. In fact it is similar to one I came up with a 
> couple of years ago only my idea at the time was to spin a Teflon 
> disk. However, that one was nogo due to the bad effects of heating 
> Teflon. The beauty of the scheme is that as the hole parts company
> from the gap, the spark is drawn out twice as quickly for a given 
> disk speed. A possible drawback is that sparks like to track for long 
> distances over insulators. Perhaps it could be souped up using 
> judiciously placed jets of air.
> 
> Malcolm