transformer losses

Discussion in 'General Electronics Chat' started by james7701, Feb 10, 2016.

  1. james7701

    Thread Starter New Member

    Jan 5, 2016
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    when dealing with losses in transformers what is Hysteresis (loss)
    and eddy current?
     
  2. Brownout

    Well-Known Member

    Jan 10, 2012
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    Welcome to AAC

    Hysteresis is a result of magnetization of the core. When current has flown in one direction, the core becomes magnetized and remains so after current has ceased to flow. This magnetization subtracts from magnetic flux produced by current flowing in the opposite direction, until the core is re-magnetized in the opposite direction.

    Eddy current is current flowing in the core under the influence of the magnetic field. Iron cores are conductive and will flow eddy current. Ceramic cores are not conductive, so eddy current will not flow in them. Iron cores are often made from thin iron laminate isolated by varnish to minimize eddy current.
     
    Last edited: Feb 10, 2016
  3. #12

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  4. james7701

    Thread Starter New Member

    Jan 5, 2016
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    Hysteresis: so pretty much current is flowing backwards(from secondary to primary instead of primary to secondary? )
     
  5. #12

    Expert

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    No. Hysteresis losses would happen if there was no secondary winding at all.
     
  6. Brownout

    Well-Known Member

    Jan 10, 2012
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    Hysteresis is caused by magnetization of the transformer core by the transformer current, regardless of whether the current is primary or secondary current. It makes it seem like current is flowing backwards, but it isn't. And current cannot flow from the secondary backwards to the primary, or forward from the primary to the secondary for that matter. Current is induced in the secondary as a result of magnetic flux produced by primary current. Likewise, current is induced in the primary as a result of magnetic flux produced by current in the secondary. Neither induced primary nor induced secondary current is a result of hysteresis. Hystersis is a whole different thing altogether.

    PS: I re-read my first response and understand the source of your confusion. When I said current flows in one direction, then the opposite direction, I mean like in an AC current. I don't mean direction like primary->secondary or secondary->pirmary.
     
  7. james7701

    Thread Starter New Member

    Jan 5, 2016
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    oh okay... i got u.. thanks so much:)
     
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