RE: secondary question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

On 8 Mar 2004, at 7:44, Tesla list wrote:

 > Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>
 >
 >  >Long streamers are the
 >  >result of repetitive growth along a hot and possibly partially
 >  >ionized channel of air.
 >
 > OK, then why doesn't that hot and partialy ionized channel of air form
 > down the middle of the secondary? :)
 >
 > Steve C.

It can if you let it. Capping the secondary coil is one way of
preventing it from happening. Having the relative creepage distance
between the ends of the coil higher inside the former than outside is
another. Allowing the highest electric field stress to form away from
the former is one way of preventing it. I have made uncapped
secondaries flashover internally by running them at a high enough
voltage to allow it. The job is made easier by drilling a couple of
holes in the form at the top and bottom and threading the wire in and
out to hold the ends fast. Perhaps one of the modelling programs can
be extended to show the internal vs external stresses under these
conditions. The point is, it will happen if you make it happen. If
you don't believe me, run your coil single shot and increase the
primary energy until a flashover does occur.

Malcolm