Re: PFC Question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Dmitry,

I think you are missing my point.  The idea is not to characterized 
the variac, but to test the statement that the leakage inductance of 
the variac causes the phase of the charging waveform to change as the 
voltage output of the variac is brought up.  It is fairly commonly 
understood that the timing of the SRSG needs to be readjusted at 
higher variac output to compensate for the phase shift occuring 
during the initial turn on process.   It has been assumed in the past 
(even by me) that the cause for the phase shift is the leakage 
inductance of the variac.  Now here is a chance to verify or 
demythify this belief.  True, what ever phase shift the leakage 
inductance causes will be dependent on the load.  So lets give the 
variac a load representative of the context of the original 
statement.  Lets measure the phase shift of the variac, and the phase 
shift of the NST and see how the two change as power is brought up 
using a NST system with a SRSG and a Cp of 2.8*Cres (for 
instance).  Then we will know :o))

Gerry R

> Original poster: "Dmitry (father dest)" <dest@xxxxxxxxxxx>
>
> > Bad idea????  Not if leakage inductance is insignificant as was
> > suggested.
>
> this idea is bad independently from the leakage inductance value,
> coz by such way we obtain  the answer only in a specific situation -
> at the specific conditions. but i`m offering to get something  more
> common, because the leakage inductance is the property of the given
> variac and by  knowing this value we can calculate the phase shift for
> _any_ arbitrary load in any arbitrary situation.
> and, by the way - i`ve no nst and i`m indifferent to how the variac
> influence it - i`ll never use nst in my psu :-D
> but variacs - always ;-)