Re: SSTC, Modes and soft switching

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

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

Hi Bob,

On 20 Aug 2004, at 13:01, Tesla list wrote:

 > Original poster: "Bob (R.A.) Jones" <a1accounting-at-bellsouth-dot-net>
 >
 > Hi all,
 >
 > As described in my message subject: Mode splitting.  By offsetting the
 > primary and secondary frequencies one of the modes of the split
 > fundamental mode disappears.
 >
 > This may be a useful configuration for an SSTC because both the
 > initial transient and the steady state current may be in phase with
 > the drive voltage if its at the frequency of the remaining mode.
 > Hence soft switching even at the start of a burst may be achievable
 > (assuming no break out)
 >
 > I have not yet done the transfer function analysis or transient
 > analysis. Which I will try to do unless someone can point out a
 > problem with this approach or error in my thinking. As always it may
 > well have already been considered.
 >
 > I believe it has been suggested that from observation of the
 > performance that a system with an offset works better. Has anyone
 > quantified the offset and or got a frequency response of such a
 > system?
 >
 > Comments anyone?
 >
 > Bob

A very loose observation from practice on my part suggests that best
performance is obtained when the primary of a standard sparkgap coil
is tuned to what would have been the lower sideband in a system with
equal pri-sec tuning with the same coupling constant. A frequency
sweep shows the LSB enhanced at the expense of the upper.

Malcolm