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Re: power transformers efficiency



Original poster: Terry Fritz <vardin@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

I have generally used:

Vsec = 1/SQRT(2) x Vpri x SQR (Lsec/Lpri)

Or

Vsec = 1/SQRT(2) x Vpri x SQR (Cpri/Csec)

The "1/SQRT(2)" was pulled from thin air :o))) But 0.7, 70%, or 0.707106781188... all give answers that pretty well agree with real world measurements and are a darn good guess at this level of calculation for a coil that is running swell.

Cheers,

        Terry



At 05:23 PM 11/19/2005, you wrote:


A classic circuit with good quenching (first 1-2 notches) hits about 70% efficiency. I believe Terry has some measurements to this value in his archives somewhere.

After measuring sec potential and also calculating it we find that:

Vsec = 70% x Vpri x SQR (Lsec/Lpri)

is very accurate for most applications.

Dr. Resonance

> Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

> > stop - my inattention - what`s the connection between the tank > circuit
> > losses and the (E x BPS)? none at all - we compare the consumpted
> > energy from the mains and the energy in the cap, not in the toroid!
> > the difference between W and (E x BPS) is determined only by the
> > losses in the transfomer/ballast - it easily can be less than 10% for
> > example, so - i`m right even more.


> Richard Quick might have disapproved of your armchair methods ;)

yeah, Obi Van Quick :-D is the _experimenter_, who thought, that
maximum theoretical efficiency  of the classical coil is 50%, but the
magnifier`s one is 100% :-)
"armchair methods" - d`you remember like Richard Hull (without doubt a
great _experimenter_) told, that the voltage on the toroid didn`t
depend from its capacitance at all? but you have objected, that
_theoretically_ it can`t exceed a definite value, in accordance with
the energy conservation law? do you remember what did he reply to you?
i can remind you :-)))

> Again, wait until you try it.

NO! i must know this BEFORE, else - what`s the use of this list? ;-)

> Bear in mind that 50Hz iron does not perform well with step
> functions from the gap being presented to it.

step function is the very small part of the energy transfer period from
the mains to the cap, isn`t it so? anyway - isn`t it possible to solve
this problem? as i`ve cope with  the power arcing problem :-)

> And high voltage current limited transformers have rather a lot of
> secondary resistance.

one mot secondary resistance is 113 ohm, i`ll have 4 of them +
the inductor resistance - not  more than ~700 ohm total. cap`s
impedance - about 32 kohm, the inductor`s one - about 12.5  kohm, so
everything will be cool :-)

>  I'm awaiting your measured results with interest.

me too by the way - even with more greater interest ;-D it`s a pity i
have to wait very long.

-----
If you ever set up a wireless power transmitting station like
Wardencliffe as proposed by Tesla, I will personally come and kick
your ass! (c) 25-07-1996 Robert W. Stephens