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  • RE: tests for magnetic materials

    Neodymium is being used in many applications where strong magnets are required,


    and other interesting ones. My "Supa Mag" magnet has one pole, is about 1" in


    diameter and has a strength of about 3500 Gauss. With it I was able to almost


    pull a car rear axle out of a canal!


    If you wind a short flat coil of wire on a former, place the magnet in the


    centre, connect the ends of the wire to a DVM, and simply swing the arrangement


    at the end of a piece of string over the ground, you can detect metal objects.


    Check out the links below.


    http://www.painreliever.com/dmaxmagnet.html


    http://www.promagnet.com/products/neo.htm


    http://eastsources.com/motor/ndfeb.htm


    http://www.arborsci.com/Data_Sheets/neo_pari.htm interesting


    http://giftsandgadgets.com/magnets/index.htm


    Cris.


    -----Original Message-----


    From: Dale Seppa [mailto:[email protected]]


    Sent: Friday, June 16, 2000 10:00 AM


    To: The Proton Mag Forum


    Subject: Re: tests for magnetic materials


    The Proton Mag Forum


    Many thanks to Cris, Peter and George for the valued input.


    Some of it quite a bit above my head but I feel I have already


    learned something and hope to learn more if you are kind


    enough to answer this posting.


    Cris: I did not quite understand if the Neodymium "Super Mag"


    is a magnetometer, gaussmeter, metal detector or what. Also


    not clear if it is the same thing that sells for 99 Quid. I


    can afford that amount so if it is simple enough that there is


    a reading and a big reading is bad and a small reading is good


    (or vice versa), I want one and would appreciate knowing where


    I can get product literature and order one as I could find no


    reference on the web.


    I keep coming back to the "hand held digitial gaussmeter shown


    at


    http:www.ascscientific/gauss.html


    and it seems to me that this or something similar would


    work??? (Does anyone know why this web address does NOT


    highlight and the one below DOES highlight???


    Peter: The only item that I know of that shows it is


    specifically to measure the "magnetic susceptibility" of


    something is a rather pricey item (I think US$2000.00 or so)


    made in Australia and found at


    http://www.geoinstruments.com.au/main.html. I also know


    TerraPlus and some other firms have them but I think price


    even greater than that shown above.


    At the risk (or probably certainty) of sounding really


    stupid - is a "magnetic suceptibility meter" the same as a


    "gaussmeter"???


    George: Your method sounds like the most exciting of the


    bunch, but considering the knowledge base that I am starting


    from and the fact that I am the only man in the world who has


    frittered away six months and haven't even selected my


    toroidal form yet, if I got started on your project, I'd be


    six feet (1.82880 metres) under before I finished. I am not


    depreciating or denigrating your greatly appreciated answer -


    only trying to interject a bit of humor into MY own personal


    failings. Or possibly "LMF".


    Again thanks and very best regards to all,


    Dale


    PS I regret boring you with these things you all know so well


    but I just can't seem to learn it from books. In fact for


    whatever reason I cannot even read a full page in a technical


    book anymore without my mind wandering so bad that I start


    the same page five times before I give up.


    ----- Original Message -----


    From: "George Davidson"


    To: "The Proton Mag Forum"


    Sent: Thursday, June 15, 2000 11:40 AM


    Subject: Re: tests for magnetic materials


    > The Proton Mag Forum


    >


    > Mag forum,


    >


    > Another angle:


    >


    > Am late on this discussion as I have been maggin in


    Mocambique


    > and have returned without malaria, cholera or yellow fever.


    >


    > I have wound a number of coils mostly solenoids and found a


    > simple test for magnetic buildup which may be useful, as


    follows:


    >


    > In the field, a magnetized solenoid will show a deviation if


    swung


    > from E-W to W-E, at worst up to 5 nT . Couldnt find any


    effect


    > of ferrous contaminated Cu wire and assumed it would cancel


    > itself out within the wire**. Did get deviations when


    mag probes


    > were rubbing against anchor chain in the bilges of the boat


    or


    > dragged across a warehouse floor or deck of a steel survey


    vessel.


    >


    > The test system I used was a hollow solenoid into which a


    bottle


    > could be placed for testing the various fluids and over


    which a


    > PVC housing with various plastics could be tested . Ran it


    > overnight at 2 A from 24v DC to get some serious


    polarization and


    > tested it in the field on top of a 3 Metre wooden pole


    which could


    > be rotated and the trace observed. Using a notebook and a


    > PICOSCOPE oscilloscope a number of measurements of various


    > type s could be obtained


    > . After that one can use the least offensive of the


    various


    > materials from the same stocks to build the final toroid


    etc.


    >


    > I like the idea of bifilar windings but always think of the


    field


    > situation like what cable to use and where the earth will


    be .


    > Cable is always a problem and stray voltages on a boat can


    realy


    > become a character -building experience. In addition


    ,cables can


    > be microphonic and change capacitance (pF) with wave


    action ...


    >


    > George


    >


    > **PS Quiz: a ferrous particle in the very centre of a


    current


    > carrying copper wire will become polarized in which


    direction?


    >


    >


    >


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