Re: Freau's efficiency theory=Success!

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

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "R.E.Burnett by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<R.E.Burnett-at-newcastle.ac.uk>
> 
> Hi John, all,
> 
> > I thought that adding PFC would stop the NST's (over-current) suffering.
> 
> I believe this is not the case.
> 
> A PFC capacitor connected across the primary of an NST draws a reactive
> current from the supply which is 180 degrees out of phase with the
> reactive part of the NST current.  The supply current is the sum of these
> two currents.  So the inductive part of the NST current is cancelled by
> the capacitive current drawn by the PFC.
> 
> This reduces the overall current drawn from the supply line,  but the
> windings of the NST still see the same total current with or without
> PFC.  It is only the line current which is reduced by cancelling the
> reactive contribution.  However, PFC is still worthwhile as reduced line
> current makes life easier for the Variac, circuit breakers and wiring.
> 
> This is one of the reasons why I believe that larger systems should be
> designed with high PF in mind from the outset.  A poor power factor in
> a large system burdens the transformer and ballast,  and requires a lot of
> PFC capacitance to make a significant improvement in the power factor.
> 
>                                                         Cheers,
> 
>                                                         -Richie,

	When the transformer secondary is loaded with a capacitor and spark
gap, how do you figure the amount of inductive reactance to cancel?

Ed