Re: "SSTC" Reliability

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

Original poster: "James B" <zebulan123-at-yahoo-dot-com> 

I know I do not post much, but I have built a few sstc
and ran them at varyious powers for extended time
periods. All of them have failed eventaly. With self
tuning topologies being the most reliable, from what I
have observed. I found little correlation (in well
built models) with power input and reliability. That
is my sstc drives seem to be as reliable at power
inputs close to there max rating as they are at lower
power inputs. I have no clue why my current designs
fail after prolonged use( I know what parts go bad of
course but can't figure out why) I would guess the
best approach would be to use a storage oscilloscope
to monitor the vital currents and voltages during
failure.
--- Tesla list <tesla-at-pupman-dot-com> wrote:

 > Original poster: "S&JY" <youngsters-at-konnections-dot-net>
 >
 >
 > I see my original question was interpreted more
 > literally than I intended.
 > I meant the term "SSTC" to be generic - a
 > semiconductor based (solid state)
 > Tesla Coil (to include DRSSTC and their ilk), not a
 > particular architecture.
 >
 > Dr. Resonance & others successfully build spark gap
 > TCs that can run at
 > science museums & other places with very minimal
 > maintenance.  I presume
 > most maintenance would be occassional adjustment of
 > the spark gap, or
 > replacement of electrodes now and then, and wiping
 > off the evaporated
 > electrode deposits nearby.  This could be done by
 > the museum staff.
 >
 > Would someone ever be able to place a
 > semiconductor-based coil in a facility
 > without incurring high specialized maintenance
 > costs, or putting IGBTs in a
 > machine-gun ammo belt arrangement, or whatever?  My
 > guess is today the
 > reliability is too low and maintenance costs would
 > soon eat up any profit
 > and would be beyond the skills of museum staff.
 > Maybe in 5 years or so we
 > can learn how to achieve spark gap reliability with
 > semiconductors?
 > Besides, the bright noisy spark gaps probably have
 > more audience appeal.
 >
 > --Steve
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Tuesday, November 09, 2004 8:22 AM
 > Subject: RE: SSTC Reliability
 >
 >
 >  > Original poster: "Aron Koscho" <kc5uto-at-wt-dot-net>
 >  >
 >  > Hi Steve,
 >  >
 >  >
 >  > As Terry and Steve W. have said, it would have to
 > be thoroughly over
 >  > designed. Also, a project of that magnitude would
 > not be inexpensive.
 >  >
 >  > However, I do believe it's possible given the
 > right amount of
 >  > time/money/expertise. There are several key
 > factors to getting more than
 >  > two feet out of a traditional SSTC such as
 > frequency, component ratings,
 >  > heat dissipation, and circuit protection. When I
 > first achieved 36" with
 >  > 7kw the system became unstable and nuked its self
 > in less than two runs.
 >  > After adding fairly complex protection and a
 > large heatsink/fan it
 >  > became more reliable. Still, the best topologies
 > for a large system
 >  > would seem to be the "DRSSTC". Regardless of the
 > chosen topology more
 >  > work needs to be done concerning coil
 > efficiencies, peak currents, and
 >  > component cooling.
 >  >
 >  > Bottom line, it can be done and hopefully some
 > will do it:)
 >  >
 >  > -Aron
 >  >
 >  >
 >  >
 >  >
 >
 >
 >