Re: More three phase fun...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Harvey Norris <harvich@xxxxxxxxx>


--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>
>
> OK.. here's another idea.
>
> You want a BIG coil, drawing a bunch o' power (say,
> 10kVA +)
>
> you want to run off three phase (so you can use
> primary side chokes and
> resonant charging)
Theres a lot of options here to discover things when
you start working with three phase. I certainly have
just playing with my AC car alternator over the years.
For example the issue of current limiting a pole pig
transformer. You can bypass all that stuff if you wish
because youre no longer dealing with the wall that
supplies practically infinite current only limited by
the house breakers.  With the three phase alternator,
you can first short the outputs, and measure the
current through the three phases, BEFORE the field is
energized. Because  the stator phases now see a
changing inductance in its core via rotation of the
fields pole faces, and due to other factors such as
remanent magnetization and the effects of metallic
rotation itself; one optains a weak current and
voltage which I refer to a parametric effect, where
this effect can be controlled to the degree by
resonant circuits attached to the alternators
circuits, so that a portion of the output is DC
rectified and sent back to the field to obtain a self
energized field of practically any voltage desired
within the limits of the machine.  Like the invention
of the jet engine, where a feedback loop of the output
energy to the input portion for compression of gas: in
some cases such a feedback loop can lead to overload,
or even explosion of the early tested jet engines.
Similarly a direct rectification of a parametric
stator output for a DC supply will soon cause a
runaway magnetic chain reaction between the field and
the stator cores, causing the alternator to go
overload which will cause insulation breakdown from
excessive heat. Very similar in principle to
microphone- speaker feedback screech that occurs that
when the two devices are brought into vicinity. When
we feed the output back into the input, a voltage
reduction device is needed at the top end of
operation, so that the fields effective voltage is
many times less then the actual operating voltage.
Water can be used to offer a voltage drop, and
resonant circuits can be used so that intially in the
parametric start up state, the feedback loop provides
a DC voltage in EXCESS of the stator voltage, causing
the feedback loop to be instantly engaged, which in
uncontrolled form may take between 20 and 30 seconds
to work. The additional advantage of having a resonant
circuit as a governor is that it should work as a rpm
dependent magneto, and only supplying large electrical
actions at a certain rpm of operation. At a 35 volt
output as a power phase in my tested example with a
small DELCO REMY model, having the diodes removed for
3 phase AC, 13% of the output wattage was recycled
back to field, but in contrast the stator voltages on
the average increased 13% beyond what that amount of
field amperage would normally produce. This should be
due to the fact that not only rotating flux leakage is
being produced for the stator output, but also the
expansion and collapse of the field beyond its
rotational amount. Because of the fact that we are now
"pulsing" the exciting field with an internally timed
DC, each phase will see a different output. The DC
pulse may begin from phase 3, but because of field
reactance the majority of the DC peak occurs during
phase 1 reading 35 volts. Phase 2 occurs during the dc
pulse collapse to zero, so it reads 25 volts, and the
intervening phase 3 reads 30 volts, which is the
timing source of the dc field feedback current which
only uses about 5 volts.
    In any case with an externally powered field, the
output short currents can be measured initially by
variac DC input to field, so that for example we know
that one field amp will produce a 10 amp supply ect.
There is then no need for any further ballasting when
the alternator is attached to a high voltage
transformer, but we can also compute whether the
supply can meet the demand. Typically we may wish to
operate at 8 times 60 hz or 480 hz. I seem to recall
that my alternator can yeild 8 amps given a 14 volt
open circuit. 14 *62 = 860 volt pole pig supply. A 5
nf cap would have a reactance of 66,348 ohms, for a
secondary current of 13 ma, creating only a primary
demand of .8 A., one tenth of its ordinary supply.

In order to bridge this gap Maximum Energy Transfer
Resonances can be designed. I have made these with 4
layers of Radio Shack Megacable Speaker wire. They are
essentially the most amount of resistance that can be
placed on the outputs, before that output starts
delivering below its shorted current rating.  The
coils at resonance actually produce the same current
available on a short of the outputs. The 2.3 mh
spirals,@ ~.8 ohms each phase using ~ 44 uf @ 480 hz
produces an acting q factor of 5, but this is obtained
at a cost that the derived higher voltage currents are
now current limited by the impedance of the individual
reactances, which for this case is 7 ohms. The
interphasal voltage rise being 1.7 times that of the
individual q factors of 5, a 14 volts stator now
produces 119 volts between the LC midpoints, where the
current limitation on those interphasal branches are
also 1.7 times less. If the interphasal voltage lines
were now placed on a step up transformer, the moment a
short is seen on the output, the entire input reverts
to a tank circuit supply, where formerly it was a
series resonant voltage rise supply, and both the
withdrawal of the voltage and amperage should help to
instantaneously quench the arc. Going back to this
example, if a pole pig 62/1 voltage step up were used
where a 14 volt stator consumed .8 A, given the 8.5
ratio of voltage step up made by series resonance,
this would now demand 6.8 A  from the primaries. If a
short were placed on the transformer the primaries
will only supply an interphasal current of 1.7 times
the reactance of 7 ohms for this example, where 14
volts would yeild a reactance current of 2 amps, so
only 1.7 * 2 = 3.4 A for a demand now placed at twice
that requirement of 6.8 A. It would be interesting to
see what would occur in this case where the supply
cant meet the demand, but I imagine only half the
expected voltage would then appear on the outputs.

So... also realizing that with the increase of
frequency the energy transfer to the LC ringdowns
increases proportionally so that energy wise running a
8 nf cap @ 60 hz is equivalent to running a 1 nf cap @
480 hz. If the arc formation is dependent on the
amount of energy transfer, a arc might be operational
at a lower voltage at higher frequencies. In the
presently designed system, it is seen the given the
fact of using a 5 nf capacitor, this would not allow
the primary current demand to develope, but if the
demand were to be met, it could then supply a 2.5 nf
limtation instead, which again is equivalent in power
delivery to a 20 nf 60 hz tesla primary.  Hence the
design factors  for the primary of higher frequency
supply input mean that the primaries can contain more
inductance, and the capacities made smaller.
HDN