Re: OLTC Thoughts

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Richard, Terry,

On 11 Aug 2002, at 21:35, Tesla list wrote:

> Original poster: "Wall Richard Wayne by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <rwall-at-ix-dot-netcom-dot-com>
> 
> Antonio,
> 
> > > Richard Hull's H2
> > > thyratron magnifier, by necessity, quenched at the first zero crossing
> of
> > > the wave form.  So only the positive half of the energy cycle was
> passed to
> > > the primary.  While a very interesting design, it is not a spectacular
> > > performer, if one measures performance by spark length.  It's a
> phenomenal
> > > research device though.  
> > 
> > This is quite strange. A Tesla coil, or a magnifier, can't operate
> > correctly without at least two polarity reversals in the primary
> > current.
> > If the current is interrupted after the first half-cycle, only a small
> > fraction of the primary energy is transferred to the secondary.
> > Where is this magnifier described?
> 
> Yes, it does seem quite strange.  Even though with only one half cycle
> there is still some energy transfer.  The coil does spark and has a
> peculiar harsh audible hum.  But, overall performance is inhibited.  I
> posted this point because Terry's OLTC will have similar very quick
> quenching which may inhibit expected performance.  I have no doubt he will
> figure out timing problems though.  A fly back diode on each switch will
> get it through one complete cycle.

*Some* IGBTs come with a body diode tailored to match the normal 
conductive channel's characteristics. 

Regards,
Malcolm

> Richard Hull designed and built this thyratron maggey.  He has demonstrated
> it at the TCBOR Teslathon.  I'm sure many on this list have seen this coil
> in action.  Richard is no longer on this list, but I'm sure he would advise
> you where it's written up.
> 
> RWW
> 
> 
> 
> 
>