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Easy way to find core saturation point

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  • Jerko Golubovic
    the core begins to take place. The core begins to act as if no iron were present in its core. Because the transformer primary looses its effective impedance,
    Message 1 of 4 , Dec 3, 2004

      the core begins to take place. The core begins to act
      as if no iron were present in its core. Because the
      transformer primary looses its effective impedance,
      where the presence of iron in the core causes that
      impedance effect; beyond that critical voltage input
      point, the primary amperage begins to skyrocket, which
      if left unchecked will result in insulation meltdown
      of the primary. Thus we can burn up a transformer,

      Hi!

      I will show you very simple method of finding core saturation point. I came on idea during my lab session with transformers and was classified as "nice" in our HAM club (once members figured out how simple it is).

      You need:

      • some wire (diameter not critical)
      • variable voltage source (variac)
      • voltmeter

      Procedure:

      1. Wind some round number of turns in biffilar way on core. Number of turns is best to be around "rule of thumb" formula for calculating transformers (in order to get sufficient impedance while still having amper-turns to saturate core) unless you want to spend too much power and heat wire
      2. Connect primary to variac
      3. Connect bottom of primary with bottom of secondary
      4. Between top of primary and top of secondary place your voltmeter

      Start rising voltage slowly. As long as you are not in core saturation, secondary voltage is following primary. Instrument will show small voltage - this represents (roughly) losses into transformer - so called "Kapp triangle".

      When you reach saturation point - secondary voltage will not follow primary anymore and difference will rise. Congratulations - you found saturation point!

      Now just measure voltage on variac. Divide number of turns with voltage and you immediately get numbers of turns per volt you can maximally apply to selected core in question.

      Of course - do not ride till saturation point in practical case; leave some gaps. (unless you want to build scalar wave detector which needs saturation point - with this one you can see if your magnet is strong enough to keep your core in non-linear region)

      Those who attempt to "do it yourself" audio output transformers for valve amplifiers will also find this useful - you can without any special equipement (like scopes) find in which part your transformer is most linear and - what is more important - did you sized your airgap in the core (used on DC-biased applications in SE amplifiers) properly or you need adjustements.

      If you plot this curve - it will be proportional to first magnetisation curve (so you can see it).

      Not very accurate - but extremely useful in practice.

      If you want to see hysteresis then you need scope and integrator (since hysteresis curve represent losses as area - it is integral and therefore you need integrator device - prefferably simple one constructed with opamp - see some books for schematics).

      You connect primary to AC voltage (mains over variac or sinewawe generator). You connect X of the scope into this. This should be H (magnetomotive force). Then you connect integrator on secondary and output of integrator to Y. This should be B (magnetic flux).

      When you callibrate properly - nice hysteresis will appear on screen. You can read:

      • core losses (area)
      • remanent magnetism (where curve cuts Y axis)
      • find saturation point

      If using sinewave generator - try to increase frequency and see what will happen.

      I am not 100% sure if X and Y should be connected this way (long time passed) - if you get rotated image - simply reverse them.

      For VTA group: try to experiment with this setup when it is placed in permanent magnetic field.

      I hope you will find this useful.

      Jerko.


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    • Harvey Norris
      ... Daka. I hope the group will find this useful/ For years I experimented with releasing power of Sf Fe magnet wafers. The ending of that was passing a
      Message 2 of 4 , Dec 4, 2004
        --- Jerko Golubovic <jerko_golubovic@...> wrote:

        >
        > the core begins to take place. The core begins to
        > act
        > as if no iron were present in its core. Because the
        > transformer primary looses its effective impedance,
        > where the presence of iron in the core causes that
        > impedance effect; beyond that critical voltage input
        > point, the primary amperage begins to skyrocket,
        > which
        > if left unchecked will result in insulation meltdown
        > of the primary. Thus we can burn up a transformer,
        >
        > Hi!
        >
        > I will show you very simple method of finding core
        > saturation point. I came on idea during my lab
        > session with transformers and was classified as
        > "nice" in our HAM club (once members figured out how
        > simple it is).
        >
        > You need:
        >
        > some wire (diameter not critical)
        > variable voltage source (variac)
        > voltmeter
        >
        > Procedure:
        >
        > Wind some round number of turns in biffilar way
        > on core. Number of turns is best to be around "rule
        > of thumb" formula for calculating transformers (in
        > order to get sufficient impedance while still having
        > amper-turns to saturate core) unless you want to
        > spend too much power and heat wire
        > Connect primary to variac
        > Connect bottom of primary with bottom of
        > secondary
        > Between top of primary and top of secondary place
        > your voltmeter
        >
        > Start rising voltage slowly. As long as you are not
        > in core saturation, secondary voltage is following
        > primary. Instrument will show small voltage - this
        > represents (roughly) losses into transformer - so
        > called "Kapp triangle".
        >
        > When you reach saturation point - secondary voltage
        > will not follow primary anymore and difference will
        > rise. Congratulations - you found saturation point!
        >
        > Now just measure voltage on variac. Divide number of
        > turns with voltage and you immediately get numbers
        > of turns per volt you can maximally apply to
        > selected core in question.
        >
        > Of course - do not ride till saturation point in
        > practical case; leave some gaps. (unless you want to
        > build scalar wave detector which needs saturation
        > point - with this one you can see if your magnet is
        > strong enough to keep your core in non-linear
        > region)
        >
        > Those who attempt to "do it yourself" audio output
        > transformers for valve amplifiers will also find
        > this useful - you can without any special equipement
        > (like scopes) find in which part your transformer is
        > most linear and - what is more important - did you
        > sized your airgap in the core (used on DC-biased
        > applications in SE amplifiers) properly or you need
        > adjustements.
        >
        > If you plot this curve - it will be proportional to
        > first magnetisation curve (so you can see it).
        >
        > Not very accurate - but extremely useful in
        > practice.
        >
        > If you want to see hysteresis then you need scope
        > and integrator (since hysteresis curve represent
        > losses as area - it is integral and therefore you
        > need integrator device - prefferably simple one
        > constructed with opamp - see some books for
        > schematics).
        >
        > You connect primary to AC voltage (mains over variac
        > or sinewawe generator). You connect X of the scope
        > into this. This should be H (magnetomotive force).
        > Then you connect integrator on secondary and output
        > of integrator to Y. This should be B (magnetic
        > flux).
        >
        > When you callibrate properly - nice hysteresis will
        > appear on screen. You can read:
        >
        > core losses (area)
        > remanent magnetism (where curve cuts Y axis)
        > find saturation point
        >
        > If using sinewave generator - try to increase
        > frequency and see what will happen.
        >
        > I am not 100% sure if X and Y should be connected
        > this way (long time passed) - if you get rotated
        > image - simply reverse them.
        >
        > For VTA group: try to experiment with this setup
        > when it is placed in permanent magnetic field.
        >
        > I hope you will find this useful.
        >
        > Jerko.
        >
        Daka. I hope the group will find this useful/
        For years I experimented with releasing power of Sf Fe
        magnet wafers. The ending of that was passing a
        vibration of one magnet to another through space
        alone. The ending magnet(S) vibrates and can be felt
        by hand. The ending magnet can have an inductor placed
        over it, and the inductor registers that vibration,
        via scoping of that vibration. It is literally a
        magnetic vibration passed through space. The closest
        idea of Sweets idea is conveyance of magnetic
        vibrations, but I cant make it continuous, when the
        source shuts down, so does the vibration. I have never
        found a vibration that acts otherwise.

        Pray tell me and the audience where such an example
        exists! As usually found these things are found by
        accidental observations. I was treating a patient via
        neon treatment al la Priore method where the ending
        body recieves the polar reception of the ending neon
        discharge as a polar capacity. I had recomended to him
        to place the neon near the actual aluminum foil
        connection against his back, which was filled with
        boils. The small neon on that connection then began to
        give an entirely different glow, a pale discharge vs
        the usual orange glow. This was the accidental
        introduction of an imperfect electrical connection,
        which manifested itself as a small air gap, later to
        make a high freq. signal riding on th 60 hz signal
        refined to make that a continuous signal to the
        patient. This was making a better treatment to the
        patient because the arc gap in the series circuit
        changed the 60 hz to many high freq signals riding on
        that 60 hz.
        It is hard for many folks to realize what I am
        talking about, so i have supplied some pictures to VTA
        list, but perhaps not enough.
        Binary Res/ Single Phase/ Neon to Magnet over C(s)
        Application.
        http://groups.yahoo.com/group/Sweet-VTA/files/ALTMAG/Dsc00411.jpg

        What is going on there is a short path to a high
        voltage expression of a C value in series with an L
        value. L and C are in resonance, from an alternator,
        but an alternate pathway is made so that the high
        voltage has another pathway directly through the SrFe
        magnet wafer, pictured by the yellow wire touching the
        top of the magnet , by its own magnetism. Also on the
        picture are white an yellow wires that go downward
        that lead to aluminum foil connections in which
        plexiglass insulation are between those foils, and
        that makes the C value for the LC 480 hz resonance. An
        alternative (short) pathway is made on the C value's
        resonant voltage rise, so that it can light a neon,
        then travel through the magnet via the top yellow
        wire, and then travel through the remaining plexiglass
        top insulator plate via dielectric conduction
        currents. Then a coil placed upon the top of this
        magnet can scope record the vibrations imposed upon
        that ferrite magnet for the simple fact that electric
        currents have been passed through the north and south
        poles of that magnet. The magnet has been vibrated,
        and the coil above that magnet scope records that
        vibration. Then one sees a saturation point of the
        magnet itself, the magnet will not release more of a
        voltage signal to the scope, in accordance to the
        voltage imposed upon it by the high voltage neon
        exposure of its path, and that signal appears as a
        sine wave, not a double sine wave with opposite
        signatures. Now we shut the energizing field of the
        alternator down, so that practically no action occurs.
        The neon does not light, yet the magnet pathway still
        exists as a short to the possible resonant voltage
        rise. Yet at the same time we see that the scope
        signal has now become very active showing much
        activity from the magnet...
        Parametric Magnet Scoping/ .2 volts@ 2 us/div
        http://groups.yahoo.com/group/Sweet-VTA/files/ALTMAG/Dsc00387.jpg

        There is a great difference between a "Forced"
        vibration, and a free vibration, where the free
        vibration itself establishes the same idea as a
        saturation point. Something can only be vibrated so
        high, and after that no further input of energy can
        make it vibrate better. The appearance of double sine
        waves has nothing to do with scalar effects either, it
        is an idiosynchrosy of recording multiple rf bursts
        per source freq on the monitored high frequency. Look
        at the thicker white signals/ they are out of phase
        with the main ones.ect... In summo I can barely scrape
        the bottom of things here, so I scrape-ich.

        That exposed magnet in this example vibrates because
        it sits on a high voltage electric field, and because
        a mechanism has been introduced to pass currents
        through its poles. Yet more spectacular examples then
        this exist. A magnet such as ferrite can be made to
        vibrate through similar examples, and magnets around
        it can be made to vibrate; through the medium of space
        alone! A magnet can be made to vibrate, and pass its
        vibration through space itself. Take my word for that
        as it has already been accomplished many years ago.
        Guess I'll load a pic to VTA to show that condition
        also, where it was found that Priore neon treatment
        involving arc gap reflected back to the magnet, in
        such a way to cause that magnet to vibrate...
        HDN

        =====
        Tesla Research Group; Pioneering the Applications of Interphasal Resonances http://groups.yahoo.com/group/teslafy/
      • Harvey D Norris
        Date: Fri, 19 Nov 2004 To: Sweet-VTA@yahoogroups.com ... Hi Mike. Thanx for your very informed comments on transformers. I thought the following would be of
        Message 3 of 4 , Dec 4, 2004
          Date: Fri, 19 Nov 2004
          To: Sweet-VTA@yahoogroups.com

          --- Mike <mikefurness2002@...> wrote:

          > Perhaps I should add a 'postscript' which was why I
          > joined this group.
          >
          > Common Knowledge, and my training, told me that, as
          > even stated in my
          > previous note, LINES OF CHANGING FLUX generate
          > voltage when cutting
          > conductors!
          >
          > Later we are told that 'in a perfect transformer'
          > all the flux is contained
          > in the core! So what cuts the wire, certainly NOT
          > flux!!!!!
          >
          > I think the answer to all our endeavours lies in
          > this little understood
          > 'IGNORED' effect.
          >
          > Has been called 'MAGNETIC 'A' VECTOR'
          >
          > Mike.
          Hi Mike. Thanx for your very informed comments on
          transformers. I thought the following would be of
          interest concerning the A field.
          Does the ferromagnetic transformer show the
          Aharonov-Bohm effect? (Fri, 27 Feb 2004)

          Bill Beauty has a page on the A vector field effect,
          which to me now has ceased to be something so exotic
          or misunderstandable. Basically the issue seems to be
          that a closed loop doesnt need to have a movement of
          field lines across its windings for it to contain
          induced voltage. The secondary closed loop containing
          magnetic flux changing in time can still have an
          induced voltage on it by the A field vector.

          Heres a reply on the subject to freenrg list.
          This E-mail is regarding Bill Beaty's "Right Angle
          Circuitry"
          http://www.amasci.com/elect/mcoils.html

          I find some misconceptions at this site, namely

          FIG. 2 A toroidial inductor is interesting because the
          induced magnetic field remains hidden within the iron
          core. If the coil was wrapped around the entire core
          rather than in one spot as shown, then the magnetic
          field would exist only within the iron core. In both
          cases the magnetic field will exist entirely inside
          the core. It is only when the amp-turns of the
          windings exceed the transformer ratings, ie
          saturation, that the magnetic field lines will start
          to emerge in space outside the core. This in turn
          will cause the core to act with less impedance, hence
          a non linear rise of input amperage vs voltage input
          will occur after a certain voltage level is attained.
          This can actually happen after a certain point of
          voltage input and cause a "runaway amperage " level to
          develope, and meltdown of insulation wires may occur.
          At full saturation the iron core is entirely
          ineffective to produce the impedance to the source,
          and the core acts as if it were replaced by air.
          Running a 120 volt rated Neon Sign Transformer at 140
          volts and beyond will start to cause these saturation
          effects, and you will quickly destroy the transformer
          insulation on the windings because of the excessive
          currents that develope from saturation.

          FIG. 3 Even if the coil of wire does not touch the
          core, it still induces a strong magnetic field inside
          the core. The gap between the coil and the iron ring
          can be very large, yet this does not reduce the
          strength of the field within the core.[Note; this is
          where I have a disagreement, see my concluding
          comments on flux density vs cross sectional area
          enclosed by loop] The mmf on the
          core should be reduced by having a larger volume
          inside the exciting windings.

          I am not exactly sure about these definitions, but if
          the inside volume area of the exciting windings is
          doubled, I would venture to say that the mmf on the
          core is halved, and vice versa.

          FIG. 4 Although the magnetic field stays inside,
          something else does come out of the core. The changing
          field within the core produces a field of Vector
          Potential which surrounds the core. This field is
          commonly called the "A-field."

          Bearden often notes things about this Aharonov-Bohm
          effect which was noted in the late fifties. In 1959
          Aharonov and Bohm published a fundamental paper in
          Physical Review which pointed out the QM implications
          of potentials as the real entities, while force fields
          were the real effects. Soon after the publication of
          the Aharonov-Bohm effect. experiments showed that, if
          the magnetic field is trapped inside a long solenoid ,
          a phase shift still is induced in the two slit
          electron experiment, even though classically, no
          contact of the enclosed magnetic field and the moving
          electrons occurs. These are Beardens comments, which I
          dont quite exactly understand, which perhaps others
          can elaborate on. I do think I understand the premise
          in far simpler words. The A field is perpendicular to
          the B field. We have two laws to understand the same
          phenomenon. The first law is the more familiar one
          which states that when a magnetic field line crosses
          an orthogonal conductive wire by moving through space
          at right angles to that wire, such as occurs when we
          rotate a magnet pole at right angle to the wire, a
          voltage is induced in that wire that can cause
          electron movement in that wire as a consequence of the
          magnetic lines of force transversing the wire at right
          angles. The second interpretation to me merely
          restates the A-B effect WHERE NO MAGNETIC FIELD
          CROSSES THE WIRE. Here the induced voltage is
          dependent on the enclosed flux (density) change
          encompassed on the interior volume area of the loops
          containing that flux change. Hence for the
          ferromagnetic transformer, the induced voltages and
          currents on the secondary already show this AB
          principle, since the magnetic field lines are confined
          to the core, and do not intersect the secondary
          windings, but those windings do recieve emf acording
          to delta B/ cross sectional area of flux change.(
          which gives the flux density) If we increase that
          cross sectional area, ie , increasing the distance of
          the transformer windings from the core, this of course
          also changes the flux density in the area enclosed by
          the loops, since the flux density itself is the amount
          of flux divided by the cross sectional area
          encompassed by the loops. Less flux density/cross
          sectional area of enclosed loops must then translate
          to a smaller induced emf. In summo something very
          exotic or mysterious is seemingly made that way by
          ASSUMING that the transformer example implies a wire
          crossing magnetic lines of force, which in actuality
          is only a convenient assumption that never actually
          occured. Sincerely HDN

          (Now some further comments on your interesting post
          reply)

          > When you wind a secondary, & draw power, the
          > secondary flux opposes the
          > primary, the flux in the transformer core tries to
          > drop, causing reflected
          > impedance, & primary current increases to maintain
          > the 'status quo', so the
          > core flux remains constant. There are many other
          > 'peripherial'
          > considerations to consider, but minor to main
          > diccussion.
          If the core flux is dependent on the amp-turns of the
          primary input, and the amount of amps on those turns
          increases as we draw power, wouldn't the increase of
          the mmf by the increased amp-turns also imply an
          increased core flux, and not a constant value as you
          seem to be implying here?
          > When you get to 'serious power' levels, the larger
          > core can give a larger
          > core factor, so less turns for same inductance, more
          > area for cooling, &
          > less turns on secondary. From memory only, as my
          > work centres on high
          > frequency devices, a small 1 - 5 VA transformer may
          > have 10 turns per input
          > volt, and a large utility one maybe 2 turns per volt
          > or less, hence the
          > cooling fins you see on them! On 'switchmode'
          > devices,
          If I understand correctly this would describe the new
          solid state neon sign transformers that output some
          20,000 hz. I am eager to learn about these devices, so
          if you have any corresponding URL's that might
          increase my knowledge in this area, they would be
          appreciated. Wouldnt we have to use a special ferrite
          core for those devices, as silicone iron starts
          becoming innefective around 500 hz?

          with their
          > frequencies of maybe 10 thousand times higher
          > frequency, 4 - 20 volts per
          > turn is achievable, thus allowing a (UK) 400v
          > rectified input, to feed a
          > transformer with only 40 turns on the primary & 1
          > (one) turn only on the
          > secondary for 10 volts out! (Not quite that simple,
          > but sufficient for
          > example).
          >
          > I have also done considerable work on 'automotive'
          > alternators, They all
          > require a 'controllable' field, due to speed & load
          > changes, which is
          > derived from output windings. Usually a bleed from
          > battery to energise, but
          > there are some (Motorola, Prestolite) which have a
          > small embedded magnetism
          > to make them 'self starting'
          Seven of Nine Reasons for Gyroscopic Conclusions
          jlnlabs@yahoogroups.com- Sat, 22 May 2004
          Think of a ferromagnetic metal as a carrier of
          uncohered electron spins. If the spins are random in
          three dimensions no magnetism is observed. If they are
          cohered in that the spins lie predominantly all in one
          plane, all in the same direction of spin, then we see
          magnetism. Think of these orbiting electron orbits as
          molecular gyroscopes. That means when we spin the
          metal, a gyroscopic reaction occurs on the
          "incorrectly" oriented spins, that tends to "push" the
          incorrect spins at an angle that forces a precession
          so that these spins all become aligned, exactly as a
          collection of randomly oriented gyroscopes on a
          spinning disc would behave. Thus macroscopic metallic
          spin itself creates a small amount of magnetism, but
          not quite the amount of magnetism that would be
          released if the metal were made into an electromagnet.
          The difference between rotational magnetism and
          electromagnetism can be detected with alternator
          experiments when we spin the field without it being
          energized. A certain amount of rotational saturation
          exists, and if the electromagnetism effect has not
          surpassed that value, it adds very little to the field
          magnetism already present. Following is a past posting
          concerning this matter...
          Sat Apr 17, 2004 11:22 pm
          Subject: Dispelling the Remanent Magnetism of Field
          Rotor Theory

          Well strictly speaking a ferromagnetic steel probably
          does generate magnetism by spin alone, which is even
          justified by considering that a gyroscopic reaction to
          electron spin orbits would justify this appearance. In
          any case the arguments used to say that remanent
          magnetism of a alternator field rotor are responsible
          for the currents generated by the unenergized field of
          a spinning alternator: those arguments would seem to
          be like the janitor sweeping the discordant elements
          under the rug. Essentially a small unknown phenomenon
          doesnt EXACTLY produce ratios of electrical action
          comparable to the real operation of the device, and
          then we are dealing in potential unknowns, as to how
          much electrical power can be obtained by mettallic
          spin alone? The electrical power we obtain in that
          circumstance might be highly efficient vs the motive
          amount of input, and truly here we are bordering on
          DePalma ideas himself, which to say the least was
          controversial some years ago. In any case using the 3
          phase air core principles; and appropriate resonances
          attached to the 3 phased inputs I was able to energize
          a 20 inch neon tube on one ended disharge which
          requires 500-600 volts, and this was made from
          ferromagnetic spin of a 480 hz alternator with
          unenergized field alone. Here is a sampling of
          evidence...

          1) Once the diodes from a car alternator are removed,
          and a three phase AC conversion of outputs made for
          pure form of conversion of its motional spin emf of
          the rotor to electrical energy without that DC
          conversion, a remarkable increase of output occurs.

          2) If we then add resonances as a filter to that
          output, and THEN rectify that output interphasingly, I
          was able to produce motion on a small 9 volt motor,
          which means motion is literally transfered through
          wires by spin, with parametric principles. The
          ordinary (unergized field)car alternator (with
          internal diodes outputing DC) of course should not
          accomplish that delivery as its output voltage is
          considerably reduced.

          3) There is a "correct direction" for inputing DC
          current to the field. The wrong direction will result
          in less stator output given the amount of field
          excitation.

          4) Remarkably The actual DC resistance of the field is
          affected in a very non-linear manner prior to the
          point where electromagnetism of the field rotor
          exceeds the pre-existant rotational magnetism.
          Initially the field appears as a much higher DC
          resistance than is actually measured without motion of
          the field rotor taking place.

          5) Rotational field "Saturation" is a consequence of
          the above observation, where little stator increase
          of output from alternator is made until where the
          elecrtromagnetic field effects surpass the rotational.

          6) DC feedback of parametic stator effects to field to
          increase that pre-existant parametric output were once
          thought impossible by this researcher, until later
          trials many years later showed that in some
          circumstances , a delayed reaction occurs, but once it
          occurs a magnetic chain reaction occurs in the field,
          instantly becoming magnetised to its highest
          saturation point, and causing overload on the
          alternator, all accomplished through ferromagnetic
          spin alone. This Demon of a Beast has never been tamed
          by this observer, [Post note; This has now been
          controlled via use of a water cell inserted into
          alternator resonant circuit to control the voltage on
          the field feedback loop] but it should be possible
          through
          zener diodes. This then could be a self energized
          field, made possible by the electrical energy of spin
          alone, but controlled in such a manner that the
          excessive feedback of that loop does not occur.

          7) 7 easy reasons for dispelling the remanent
          magnetization of field rotor myth. Once the field is
          ACTUALLY energized, and then turned off, we see an
          increase of parametric readings. THAT is that totality
          of remanent magnetisation effect, which of course is
          lost after a certain time after motion of the field
          rotor has ceased. It is ONLY that amount of increase
          that should be attributed to remanent magnetism of the
          field pole faces, and of course the ordinary
          parametric levels of operation are then seen when that
          remanent magnetism ceases to be present...

          HDN

          Again another post on this matter;
          Several years ago I started working with
          the concept of a self energized field for an
          alternator. By taking one of the three phases of AC
          output, and rectifying it back to DC current for the
          field, which is a rotating electromagnet, a runaway
          magnetic chain reaction occurs, causing the alternator
          to go into overload. This process can start from an
          unenergized field, because of remanent magnetization
          of the field rotor, because the assembly actually also
          acts as a parametric generator,(Delta L on the stator
          windings over time acts when the pole faces rotate
          inside the stator core, causing a changing inductance
          to be recorded on the stator windings, which is the
          principle of a parametric oscillator), and thirdly due
          to the fact that metallic rotation itself of a
          ferromagnetic metal causes a gyroscopic reaction of
          the free unpaired electron spins in the electron cloud
          of the metal, with the macroscopic result that
          metallic spin in of itself also causes a weak magnetic
          field to be exhibited. This is also prooved by the
          fact that there is a different efficiency of result in
          the field's rotating electromagnet dependent on which
          polarity we input DC amperage through the field. If
          the DC field amperage creates a magnetic field in the
          same direction as what the spin itself establishes,
          that is the CORRECT polarity to use in establishing
          the field, and if it is in the opposite direction, it
          must fight the natural tendency of the magnetic field
          that itself is estqablished by spin, hence the wrong
          direction of DC amperage input means less efficiency
          of the alternator per input of the DC fields amperage.
          Going even further with DC field studies, it is found
          that both BACK emf effects exist; when the fields
          amperage creates a magnetic field below that of the
          pre-existant magnetic field made by rotation, and even
          more importantly FORWARD emf effects can be shown,
          where the field starts loosing resistance after
          exceeding the rotational pre-existant magnetic field
          of the field rotor. This also is easily proovable,
          where the DC resistance of my field rotor is 20 ohms
          when not moving, some 100 ohms at the lowest levels of
          amperage introduction to the field after rotational
          movement is established, and finally it becomes around
          5 ohms at the point of action I use in experiments.

          > You stated that you couldn't exceed 40 volts?
          No, what I meant here was that I wouldnt want to
          operate past 40 volts for prolonged time periods
          because of excessive stator core heating. Actually the
          alternator I have used in experiments is a Delco Remy
          model that is not a large amperage output model. About
          50 or 60 volts output I start hearing significant
          bearing knocking noise so I dont press the issue and
          operate in sensible power output ranges.
          > probably because the unit
          > wasn't going fast enough, a 12 volt bobbin probably
          > saturates at about 18
          > volts, so more core current just causes rapid
          > heating.Voltage out (assuming
          > constant energisation) is directly proportional to
          > speed, rate of change of
          > flux,(as in tacho- generator) so much more voltage
          > is available if you run
          > the device faster.
          Yes my pole face field rotor has 7 pole faces, where I
          have first tested at 190 hz, and now at a medium rpm
          range that outputs 480 hz. Since frequency may also
          be an issue with ferromagnetic stator saturation I
          wish to keep things below 500 hz, as I have taken out
          the diodes to explore the effects of attaching
          resonant circuits to the AC output. I have also found
          that attached transformers seem to have a non-linear
          rise of impedance in accordance with increasing the
          frequency input. I would think that operating near 500
          hz would be operating near the top limit for
          ferromagnetic transformers. These transformers
          sometimes also bleed off a lower harmonic into the
          sound spectrum producing a whine noise that resembles
          a high pitched musical note. Plexiglass plate
          capacitors used in 480 hz high voltage resonances
          produce this musical note whine at a very high volume.
          > As a precursor to designing a high speed
          > generating set, I did some
          > experimenting with a prestolite 24 volt 175 amp
          > truck alternator. The core
          > was energised from a seperate 24 volt constant
          > supply, rectifiers were
          > changed for high voltage 800V PIV devices & unit was
          > run into a very large
          > water cooled variable resistance nerwork.
          > The speed at which the rotor started to 'grow' was
          > at 24,000 RPM, off load
          > voltage was about 310 volts,(declining rapidly with
          > load), maximum
          > continuous power out, 26KW
          Hmm, I am jealous now, I need to set up a alternator
          that has more guts and power, your work sounds
          interesting.
          > An interesting discovery was that (as per
          > transformer) when the 'ampere
          > turns' in the stator equalled the ampere turns in
          > the core, (at 175 amps)
          > the unit would give no more, even into a short
          > circuit load, & therefore
          > unloaded the prime mover & didn't overheat. maximum
          > power out was obtained
          > by suitable load matching.
          This sounds somewhat interesting because when I
          arranged things according to the principle of maximum
          energy transfer and resonated those resistances made
          into the form of a spiral, I was also able to output
          larger amperages without any significant stator
          heating occuring. It is only when I put interphasal
          loads on the resonance's voltage rises that
          significant stator heating then is observed. I called
          the spirals METR components, {Maximum Energy Transfer
          Resonances}. What seems to go beyond the established
          electrical theory is that they obey the aspect that
          the voltage drop in comparison to open circuit voltage
          will be about 50%, but acoording to theory there is
          also supposed to be a corresponding 50% drop of
          amperage compared to the value obtained when shorting
          out the outputs. Instead these resonances obtain the
          same value of amperage that will be found when the
          outputs are instead shorted. The METR components were
          made by making R(load) ~ = to R(int) which was found
          by noting what voltage appeared across the outputs
          when shorted, and the dividing the obtained amperage
          by the obtained voltage, giving a value near a half
          ohm for this particular Delco Remy alternator.
          Everything had to be duplicated for all three phases,
          or else different values for R(int) were obtained. A
          short on two phases produces more current on the
          phases then for the case when all three phases were
          shorted.
          > It was decided that this arrangement would not be
          > ideal, so I called in
          > outside help to design a 90,000RPM direct drive
          > alternator (genset to be
          > powered initially with Russian cruise missile
          > engine, 50KW at 90,000RPM)
          > Permanent magnet, no brushes at that speed, Output
          > voltage 210 off load & 90
          > volts full load, boost transistor to take this to
          > the 800v required for PWM
          > line invertor.
          Whew how in the hell can bearings stand such an
          excessive rpm! I also have a set of paired bus
          alternators that I think are known as reluctance
          alternators. Those alternators have a cup shaped field
          that does not revolve! Instead a tight clearance is
          involved where a set of rotating pole faces rotate
          around this metallic cup. The pole faces "grab" the
          fields magnetism by being a path of least reluctance.
          Since the field itself does not rotate, there are no
          brushes or slip rings in that model.
          > Whole device intended to weigh 40KG (90 pounds) &
          > highly portable. Still
          > have some very large transistors laying around.
          Each of the bus alternators also probably weigh at
          least 90 lbs also. They even have inputs for oil
          cooling like a transmission! These are some monster
          machines that need a 240 volt AC motor to turn the
          pair which outputs 360 hz.! The stator windings are
          made from varnished thick copper bus bar type windings
          intersecting segments of laminated silicone iron. The
          pole faces rotate just underneath this assembly. Only
          59 stator winds are around the circle, making for 18
          winds per phase. I have not turned this machine on for
          several years, as the smaller alternator provides for
          a convenient tool for researching effects of
          resonance, and also I dont have 240 VAC in the garage
          and must use a long extension cord taken from the air
          conditioning 240 outlet. Since these alternators are
          paired by a variable connection pulley, this gives the
          option of making a special 6 phase system, where any
          desired phase angle between the two 3 phase systems
          can be procured. Spent a lot of money on that project!
          The AC phases are also isolated, meaning that they can
          be outputed in either delta or wye, or in perfect
          isolation.
          > Sorry to have wandered so far 'off topic' thought
          > it might have some
          > general interest.
          Enjoyed the interchange of information... Thanks, it
          wasnt off topic for me...HDN
          > Mike.
          >
          > Mike. J. Furness.
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