[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 3 phase distribution transformer question/ 360 hz tesla coils??




--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "Bert Hickman"
> <bert.hickman-at-aquila-dot-com> 
> 
> Tesla list wrote:
> > 
> > Original poster: ghub005-at-xtra.co.nz
> > 
> > I have been offered a three phase 15kVA, 11kV,
> 240/415 volt
> > distribution transformer - free if picked up.
> > 
> > What would happen if this unit was run on single
> phase 240V? Apart
> > from derating the output voltage by sqrt(3), can a
> three phase core
> > cope without all of the separate magnetising
> currents?
> > 
> > I would appreciate any information or hearing
> about the experiences
> > that others have had with single phase operation
> of three phase
> > transformers.
> > 
> > Safe coiling,
> > 
> > Gavin Hubbard
> Gavin,
> 
> Nice catch! You should be able to use one or two of
> the three LV
> windings, but you'll need to leave the third set of
> windings
> open-circuited. You COULD energize the transformer
> from a single LV
> winding and pick off HV off two of the secondary
> windings at reduced
> power.
> 
> To get maximum power from a single phase source,
> you'll want to use two
> of the LV windings. However, you will need to insure
> that they are
> connected so that the magnetic flux from one is in
> the same direction
> (via the magnetic circuit through the core) as the
> flux from the other
> winding. 
Thanx for this excellant info. In the past I had
noticed from combining phases from diodeless
alternators that combining two of these phases in
series could produce a greater voltage amplitude than
a single phase, but as you say all three phases cannot
be incorporated. A look at reference books show that
if all 3 phases were wired in series this produces
complete voltage cancellation, therefore zero current
draw. This seems most unusual since shorting a single
of these phases produces maximum amperage. I now have
a functional dual 3 phase alternator, where each
alternator can be adjusted to any phase angle with
respect to the other set. These are real monster bus
altenators driven by a  220 volt 5 hp single phase
electric motor. However they are designed for high
amperage, not high voltage,each phase only producing
25- 30 volts, so a 3 phase transformer scheme is being
used. The immediate problem is that the frequency is
360 hz. I would think a conventional iron core
transformer would heat up, but thinking of the higher
impedance at this frequency this may not be a problem.
Heres what a colleague wrote;
Many power transformers are rated form 50 to >400 Hz.
The reactance may limit the current and power at
higher frequencies, so they should not overheat at
400Hz. High magnetization currents would be from
operating a 400Hz transformer at a lower frequency,
such as 50 or 60Hz. There may be more hystersis loss
at 400+ Hz, but this is "iron" loss, not in the
copper.

Now what really intrigues me is the next possibility
of making each alternator set of phases 90 degrees out
of phase, which is what I am doing for various
research purposes anyways. However my voltage input
for these purposes needs to be about 10 times what the
alternators supply, so three phase transformers in
step up function are to be used. If you could take the
time to look at this idea;

The use of a poloidal winding along with the usual
toroidal winding has been the subject of several
patents.
If the poloidal and toroidal windings are driven at
quadrature the B field rotates around the torus with
zero hysteresis according to the patents.



http://www.patents.ibm-dot-com/details?pn=US04595843__


A transformer utilizing a rotating flux for saturating
the entire core. The transformer uses a core
configured such that a vector sum of the induction
produced by two windings in the core rotates through
360°. This is accomplished by arranging the component
induction vectors to be perpendicular and the source
voltages associated with each of the component
induction vectors to be 90° out of phase. If the
inductions are of equal magnitude and the vector sum
is sufficient to saturate the core, rotation of
the vector sum saturates the entire core and the
transformer experiences a very low or nearly
negligible hysteresis losses. Various topological
configurations for the core, including a toroid, are
described. The transformer windings can be arranged
for single, two-phase, three-phase, or
multi-phase operation.

My important question then become since I already have
the 90 degree phased inputs as  a dual alternator
input, cant I use the three phase tranformer in a step
up application where each phase constructively
interacts  to eliminate these hysteresis effects? Isnt
poloidal winding the ordinary windings found on power
transformers? Now for my last unanswered question,
couldnt I construct another voltage rise past a 10/1
ratio to drive two tesla coil primaries at 360 Hz?
Wouldnt it be a wonderful thing to run 2 tesla coils
90 out of phase, and have that input phasing
arrangement correspondingly increase the efficiency in
its driving input transformers! I guess an application
of NST's would not fill the gap here? Any ideas?
Essentially then because of transformer problems
should it be stated that it is impossible to make a
360 hz tesla coil, unless special measures as these
are used? More patent info;

http://www.patents.ibm-dot-com/details?pn=US04639610__


A rotating flux transformer having at least two
magnetic cores, each in the form of a torus, with each
magnetic core having poloidal and toroidal
windings. The need for breaking the torus and bringing
out leads from the poloidal winding is eliminated by
passing each torus through the core window of the
remaining torus, or tori. Each poloidal winding is
shorted, with the toroidal winding, or windings, of
the other magnetic core or cores, inducing
an excitation voltage into each shorted poloidal
winding which is 90° out of phase with the voltage
applied to the toroidal winding on the same magnetic
core.

http://www.patents.ibm-dot-com/details?pn=US04638177__


A rotating flux transformer which includes a magnetic
core having poloidal primary and secondary windings
and toroidal primary and secondary windings.
Quadrature flux is produced in the magnetic core by
connecting one end of the poloidal primary winding to
the center of the toroidal primary winding.
The quadrature flux combines vectorially to produce a
rotating induction vector in the magnetic core.

Again since I already have the 90 degree input,
shouldnt I be able to produce this rotating induction
vector by merely attaching those inputs to any two
phases on the three phase transformer? Appreciate any
input as I am over my head on this 3 phase thingy. But
it just seems like 90 degree phasing is a thing that
folks have totally overlooked the possibilities
involved, and building a set of tesla coils from the
power input might further show the possibilities
involved with what I have termed nature's correct
power input. I will shortly have a web page up showing
this power system in NE Ohio, visitors are welcome.

Sincerely Harvey D Norris, Tesla Electric Co.






=====
Binary Resonant Systemhttp://www.insidetheweb-dot-com/mbs.cgi/mb124201

__________________________________________________
Do You Yahoo!?
Get Yahoo! Mail ­ Free email you can access from anywhere!
http://mail.yahoo-dot-com/