does arsg switch ac or dc?

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

Original poster: "Laurence Davis by way of Terry Fritz <twftesla-at-qwest-dot-net>" <meknar-at-hotmail-dot-com>

srsg switching 50/60hz makes sense. does an async gap switch ac? Is that why 
a sync gap is preferable?  i would think to get an async gap to
perform would be with a dc supply.  rectifying 15kv, would that be an mmd 
bridge? ;) or are there single diodes available that can handle 15kv? (bet 
they're expensive).  if motor speed could be regulated, then an arsg 
switching dc could be beneficial.

larry.