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# Dave Meekers Induction Motor in FEMM example: a question

- To: <femm@yahoogroups.com>
- Subject: Dave Meekers Induction Motor in FEMM example: a question
- From: "Douglas Stevenson" <Douglas@magtech.co.uk>
- Date: Wed, 9 Oct 2002 13:53:29 +0100
- Thread-index: AcJl5GdWIBB19ZSSR6uEAgGo8PgsEQJq3D7g
- Thread-topic: [femm] Re: Induction Motor in FEMM

    I have a few conceptual questions regarding this model.

    The example clearly demonstrates the "deep bar" effect on the rotor at
    different frequencies. The current density in the rotor bars is clearly
    redistributed towards the outer edge of the rotor at reasonable starting
    frequencies of 50-60 Hz.

    However, how would one assess the so-called "Proximity effect" in the
    stator windings? At higher frequencies of applied current (say a few Khz
    caused by a current source with severe distortion), the presence of a
    winding with parallel turns or conductors that are large w.r.t the skin
    depth, would create an effect similar to the deep bar situation. The
    ferromagnetic slot would cause the current density to be "redistributed"
    in those stator windings, once again producing an effective AC
    resistance far greater than the DC resistance, and a corresponding
    increase in undesirable losses.

    One would cleary need to define a large number of conductors/turns with
    their own circuit properties in FEMM, but how would one assess which
    regions of the individual conductors/turns have higher and lower
    resultant current densities? Each condcutor /turn has both its self
    inductance, causing the skin effect, and the mutual inductances with all
    the surrounding conductors/turns as well as with the eddy currents in
    the core causing the proximity effect. How and which would one define
    boundary conditions for the individual turns/conductors?

    Douglas Stevenson

    -----Original Message-----
    From: David Meeker [mailto:dcm3c@earthlink.net]
    Sent: 27 September 2002 06:18
    To: femm@yahoogroups.com
    Subject: [femm] Re: Induction Motor in FEMM

    Ok--I've been threatening to make an example of how one might go about
    analyzing an induction motor using FEMM, and now I've done it. Well,
    at least I've got a draft of an example anyhow...

    If you're interested checking out this example, I've put it at:
    http://femm.berlios.de/2horse.zip

    This example goes through the identification of parameters in an
    induction motor model with FEMM. Torque results from the circuit
    model are then compared to torques predicted via stress tensor
    integrations. Some additional issues are also presented that are
    important to consider for the purposes of design and comparison to
    experimental results.

    If I've made a mistake in the example, please point it out to me--I
    don't usually do "normal" induction motors...

    Dave.

    --- In femm@y..., Lindolfo Marra <lindolfomcneto@y...> wrote:
    > I am work with simulation in the induction motor. Simulation lf
    loked rotor conditions and running conditions.The simulation is not
    good. Femm(groups), you make this simulation, please you can send the
    simulation(rotor conditions and running conditions) in the FEMM. thank
    you
    >
    > ---------------------------------
    > Yahoo! PageBuilder - O super editor para criação de sites: é grátis,
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