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

# Re: BH data

- To: femm@yahoogroups.com
- Subject: Re: BH data
- From: "mikejhutch" <mhutchings@solartronmetrology.com>
- Date: Thu, 24 Oct 2002 15:31:29 -0000
- In-reply-to: <5.1.0.14.0.20021023131401.01d62ad0@staff-mailin.lboro.ac.uk>
- User-agent: eGroups-EW/0.82

    --- In femm@y..., Keith Gregory <k.gregory@l...> wrote:
    > Mike,
    >
    > I think you would find that static finite elements models with
    single
    > valued magnetization characteristics would give pretty good
    approximations
    > of field distribution and winding inductances in the 50-60Hz types
    of
    > applications where the materials are laminated. Although
    calculating
    > inductances in saturated conditions is complicated. Loss
    calculations even
    > at 50 or 60 Hz are not as straightforward. Operating in Khz I
    really have
    > no idea how good results would be.

    A basic model LVDT model using mumetal core at even 100 Hz shows
    pronouned skin effect. At 5kHz there is a danger of saturation near
    the material surface at normal drive levels.

    >
    > >I am currently interested in trying to observe Barkhausen noise for
    > >NiFe materials. I expect to use up to about 100 Hz field for this,
    and
    > >believe that the spectrum of the noise will contain much
    information,
    > >if it can be unravelled; early days yet. Comments are very welcome
    >
    > The classic demonstration of Barkhausen jumps is done with "DC"
    > magnetization, usually with a permanent magnet. I have a vague
    memory of a
    > paper describing a different way which can produce noise displays
    on an
    > oscilloscope. I'm not sure what information it would contain
    though, what
    > had you got in mind?

    I hope to use LF ac to cycle the jumps and give larger noise output.
    Literature suggests that Barkhausen noise can indicate heat treatment
    and internal stresses, inter alia; as properties of cores are
    affected by handling stresses I believe BN can provide an insightful
    tool into known quality issues.

    > In addition, if my memory serves aren't there several different
    Radiomental
    > alloys differentiated by a number such as Radiometal 36?

    Yes. The 36 refers to % nickel in the alloy. Varoius types give
    different permeability / resistivity / cost materials for different
    applications.

    Mike

- Follow-Ups:
  - Re: [femm] Re: BH data
    - From: Keith Gregory <k.gregory@lboro.ac.uk>

- References:
  - Re: [femm] Re: BH data
    - From: Keith Gregory <k.gregory@lboro.ac.uk>

- Prev by Date: Re: BH data
- Next by Date: Direction of Magnetization, Other Flux patterns
- Previous by thread: Re: [femm] Re: BH data
- Next by thread: Re: [femm] Re: BH data
- Index(es):
  - Date
  - Thread