RE: MMC cap bank

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

Original poster: "Lau, Gary by way of Terry Fritz <teslalist-at-qwest-dot-net>" <gary.lau-at-hp-dot-com>

I have to concede, you are correct.  The cap will ultimately fail.  The 
question is when.  But the cap maker is spec'ing that cap for continuous 
24-7 operation under the most adverse conditions.  In a TC application, we 
typically demand far less life from a cap.  For most of us, if we run our 
coils for a couple hours over the course of a year, that's probably all we 
need.  If a coil were to be run for several hours every day, in a museum 
perhaps, then a far more conservative design would be required.

For recreational coiling though, the norm has been to design MMC's based on 
the DC spec.  Folks have been doing that since the advent of MMC's, and 
it's very rare that a failure is seen.  Certainly less often than with 
rolled poly/foil/oil caps!

Regards, Gary Lau
MA, USA


Original poster: "Dr. Resonance by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>

The manufacturer has spec'd the rating at 900 VAC.  He's running the caps at
14.4 kV (mfgr rating is only 9 kV AC).  It's not rocket science.  He's
exceeding the manufacturers ratings severely.

DC ratings have to be completely ignored because RF corona will occur at the
caps plate edges.  They will fail --- it's only a question of when failure
will occur.

Dr. Resonance

  >
  > I'm not sure I agree with this dismal assessment.