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Re: which coilform parameters best?



Original poster: "boris petkovic by way of Terry Fritz <twftesla-at-qwest-dot-net>" <petkovic7-at-yahoo-dot-com>

Bart,
.
> 
> > > Assume a 14.4/347 (5kva) pig is pushed to 10kva
> with
> > > the 0.1uF cap = 10.4ms to charge cap to 20362
> Vp.
> > >
> > > 120 bps = 8.33ms = 19900 cap V = 19.83 joules.
> > > 240 bps = 4.17ms = 16900 cap V = 14.28 joules.
> > > 480 bps = 2.08ms = 10955 cap V = 6.04 joules.
> > >When the cap size gets up there, I think it would
> be advantageous to go
> > > higher, especially if one wants to play with
> faster breaks.
> > ---
> > This is relative again.Depends on stray
> inductance( +
> > ballast) and Cp size you deal with.These two make
> > possible many combinations as concerns same
> charging
> > frequency of system.There is case where Cp small
> and L
> > large,and case where Cp big and L small giving the
> > same charging frequency.
> 
> Will we ever see a case where Cp is small in
> comparison? Maybe in an
> extreme case, but I would think
> rare.
> 
> > Cp small results in higher voltage, than Cp large.
> 
> Like you said, it's relative to the inductances. In
> your case of a small Cp
> and large L, current has
> changed, and if selected for the same charging rate,
> the voltage would be
> the same as, well as the
> time (assuming power factor was unchanged).
---
Actually it's not.Take my post from theoretical side
of view.
Larger inductor and smaller capacity results in
somewhat higher peak voltage due to higher charging Q.
Since both Qs are pretty high ,in usuall
arrangments,in 120 BPS sync mode ,the difference
between V1 and V2 is negligible to bring in question
which option is better regarding energy stored.
I tend to agree it would be one with larger Cp.
---
> 
> > You refer to VA figure ,but what is more important
> is
> > W (real power).If one doesn't care about that, may
> get
> > very poor overall efficiency of charging system
> > despite respectable VA levels drawn from mains.
> 
> Yes, in keeping with the transformer ratings and to
> get the point across.
> But regardless of
> efficiency's, apparent or real power, the affect of
> the transformer under
> the stated conditions still
> apply, simply at better or worse efficiency's.
> Assume if you will, the
> previous va numbers were 100%
> efficiency (then va=p). Anything less (va < p) will
> make those numbers even
> worse for the metered
> power in and strengthen the case for more current.
---
a)Loseless case and Fcharging=Fmains.Even here there's
only one case,which is further idealization in
idealization,where VA=W,and under such case ,despite
no looses and resonance attained transformer doesn't
draw infinite power.
Other conditions being equal,but capacity not
discharged when all off magnetic energy in circuits
collapsed to absolute nill,makes numbers of power go
up very quckly.
---
> 
> Maybe what your showing here is that it is also a
> good idea to attain the
> highest power factor
> possible on any given charging system. And that, I
> totally agree.
---
Mainly yes ,it was.
b)Reality.Fcharging~Fmains,and overpowering
transformer,Nx120 BPS mode.
It's not only due to distortion of current-voltage
waves (higher harmonics mixed back with source
frequency),but it's transformer itself not made for
that way of delivering power.
Power factors sequence decreases faster than
expected,as you switch to 240,480 BPS etc. fittingly
overpowering it with VA.

regards,
Boris