Re: Primary and Secondary?????

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Hollmike-at-aol-dot-com>

Nolan, 
  The main thing is to try to get very close to 'critical' coupling.  If you
tune your coil in an undercoupled state, then your primary and secondary
circuits tune at the same frequency.  You then can increase the coupling until
you reach critical coupling, which transfers the maximum energy to the
secondary. 
  If your primary and secondary are overcoupled, the maximum transfer of energy
occurs only if you detune your primary(there exists two frequencies - one above
and one below the res. freq of the secondary and equally offset).  This is
often referred to as the 'camel hump' due to the shape of the graph of power
transfer vs. frequency. 
   The real problem with overcoupling is that now you have two different
frequencies working which will create constructive/destructive interference
patterns.  The obvious visual effect of this is the racing sparks along the
secondary coil and possibly arcing between the primary and secondary.   The
interference patterns cause point of high voltage to appear at spot below the
top of the coil and thus the racing sparks. 
Mike