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# Re: [femm] Re: various

- To: <femm@egroups.com>
- Subject: Re: [femm] Re: various
- From: "Bruce McGee" <mcgee@mcmillan-mcgee.com>
- Date: Mon, 22 May 2000 18:26:25 -0600
- References: <dd.4a841c8.265a97a3@aol.com>

    Recommend that you stay with peak quantities since it follows naturally from
    the quasi-steady state formulation of Maxwell's equations.

    ----- Original Message -----
    From: <dcm3c@aol.com>
    To: <femm@egroups.com>
    Sent: Monday, May 22, 2000 8:01 AM
    Subject: [femm] Re: various

    > In a message dated 5/18/00 5:34:54 AM Eastern Daylight Time,
    > rlbrambilla@cesi.it writes:
    >
    > > These are my suggestions that, I hope, require simple modifications.
    > >
    > > GLOBAL : a command for a custom dafault settings (units, materials
    etc.).
    > > Actually I use a template file.
    >
    > Including some sort of standard (but user-modifiable) template would be a
    > good idea.
    >
    > > GEOMETRY : commands for inserting points and lines by keyboard. In
    large
    > > packages there are tens of this commands, most of them never used. Only
    two
    > > commands are strictly enough (but unavoidable) for the model precision
    :
    > > Point(x,y), and Line(x1,y1,x2,y2).
    >
    > You can do this already. In pretty much any situation where a specific
    point
    > needs to be specified, you can hit the <tab> key. A dialog will pop up,
    > allowing you to enter the coordinates of a point by keyboard, rather than
    > having to use the mouse.
    >
    > > RESULTS : similar Point and Line keyboard commands to read results and
    to
    > > paste values to the clip-board for exporting. Actually it is possible
    to
    > > paste only the field picture, but I need to export values to other
    programs
    > > for successive elaborations.
    > > Fine will be to have command to select the quantity I want the contour
    > > lines (as in actual xy-plot).
    >
    > You can get the data from an xy plot to disk by checking the "write data
    to
    > text file" check box in the dialog where you select what sort of xy plot
    is
    > to be created. Having an option to send it to the clipboard might be a
    good
    > idea as well.
    >
    > > And now a little remark.
    > > In frequency dependent problems, inserting point currents,
    > > I insert peak value, i.e. Io for a varying current Io exp(jwt).
    > > Reading the results for a selected point I find Bx, By, |B|.
    > > I suppose again Bx exp(jwt), By exp(jwt).
    > > Now your |B|=sqrt(|Bx|^2+|By|^2) and the time factor is cancelled
    > > by conjugation. So it may be considered an "istantaneous constant
    modulus".
    > > Usually we need the time averaged over a period so this value
    > > has to be divided by sqrt(2). To avoid this external operation
    > > I insert Ieff=Io/sqrt(2) as a point current. But in this case
    > > I cannot suppose Ieff exp(jwt)! So it seems to me that the output
    > > <|B|> = |B|/sqrt(2) and peak value insertion would be more clear.
    >
    > In an attempt to be consistent and make things flow sort of "naturally"
    from
    > the magnetostatic to harmonic cases, I have kept all results in terms of
    > amplitudes, rather than RMS quantities. I might see about putting in a
    > choice of "modes" for the output results, either the complex amplitudes
    (as
    > it does now), amplitude and phase angle, or RMS quantities.
    >
    > > Hoping for future improvements,
    > > sincerly yours Roberto
    >
    > Thanks for your comments.
    >
    > -----------------------------------------
    >
    > In a message dated 5/18/00 8:16:04 AM Eastern Daylight Time,
    > eckart.nipp@m-v-l.de writes:
    >
    > > A difficulty is the rectangular selection tool. With that it is
    comparably
    > > troublesome to select e.g. a rotor of an asynchronous motor with all
    its
    > > slots but not any part of the stator. This is particularly hard if the
    > > airgap is short. Maybe an optional circular selection tool can be
    > > developed. Also a deselection possibility, e.g. by holding shift, would
    be
    > > useful. When playing around with a not predefined geometry also the
    > > possibility of moving parts per mouse may be useful.
    >
    > Different selection tools might be useful. With the way that the
    selection
    > tool currently works, you can use it multiple times to select all the
    parts
    > of a geometry that has a more complicated shape--the previously selected
    > stuff doesn't automatically get deselected.
    >
    > Anyhow, a good way to analyze a rotor at different positions in the 3.0
    > version is to assign all of the parts of the rotor to one "Group" as you
    > build it. Then, you can select the entire rotor with just one right-click
    of
    > the mouse when the editor is in "group" mode.
    >
    > > Can the circuit property also be used to define the voltage of an
    exciter
    > > coil which is aymmetrically placed so that it is unknown in the
    beginning
    > > how the total voltage distributes on forward and backward pathes?
    >
    > There's a feature that's sort of "hidden" having to do with circuit
    results.
    > In the postprocessor, choose the View | Circuit Props selection off of the
    > main menu. This allows you to see what voltage was required to impose a
    > prescribed current, or how much current was obtained from an applied
    voltage
    > for a particular circuit (as appropriate). This might allow you to get
    the
    > information that you are after.
    >
    > > Now I think I also found a bug in the group copy tool. When I chose a
    > > circle consiting of two 180deg arcs and copy it as a row, i.e. several
    > > copies at once, I get the desired circles but in addition a row of
    anchor
    > > points.
    >
    > I've been able to duplicate this bug--many thanks for catching it. This
    was
    > the sort of thing that I was hoping to have people find with this beta
    > version....
    >
    > > Greetings
    > > Eckart
    >
    > Dave.
    > --
    > http://members.aol.com/dcm3c
    >
    >
    > ------------------------------------------------------------------------
    > Best friends, most artistic, class clown Find 'em here:
    > http://click.egroups.com/1/4054/2/_/5054/_/959004088/
    > ------------------------------------------------------------------------
    >
    >

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    - From: dcm3c@aol.com

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