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Transformer analysis

  1. Apr 14, 2012 #1
    I am asked to compare analytical values of the loaded transformer with measeured values of the transformer. I have got no clue how to do that. The transformer is singl ephase 230/115V with rated secondary current 0.43 A.
    According to open circuit test the Rcore = 15.9kOhm, Xcore = 10.5kOhm. From SC test Req= 80 Ohm,
    Xeq = 33.8 Ohm, Zeq = 86.8 Ohm

    I have values of load test as follows. The load is connected to secondary R= 150k Ohm,
    Vp = 211V, Ip= 24 mA, Pp = 3.2W, Vs = 115.1, Is=0.75 mA.

    I am not sure what to do with that data. I also dont know how to find actual efficiency of the transformer. What is the power output of that transformer?
    Thank you
     
  2. jcsd
  3. Apr 14, 2012 #2

    rude man

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    What exactly is "Rcore" and "Xcore"? Also your "ewq" parameters. How exactly were they measured?

    What you should have measured id
     
  4. Apr 14, 2012 #3
    have you been introduced to an equivalent circuit model? I would guess that you have to compare your results from the 150k loaded experiment, to the results from the open and short circuit experiments.
     
  5. Apr 14, 2012 #4

    rude man

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    What exactly are "Rcore" and "Xcore"? Also your "eq" parameters. How exactly were they measured?

    What you need is:

    with no other connections to the transformer:
    primary inductance L11
    primary resistance R1
    secondary inductance L22
    secondary resistance R2

    with primary excited:
    secondary voltage, open-circuit secondary: V2(oc)
    secondary voltage, loaded secondary: V2(150K)

    You might also determine the reverse voltage gain, i.e. V1(oc) and V1(150K) with V2 excited, although that should be redundant.

    EDITED:
    Not sure what the intent here is. Looks like you are to do just the unexcited measurements (the first four) and then assume a fully coupled transformer (k = 1.0) and compare the caculated output voltage with the measured one. But I'm just guessing.
     
    Last edited: Apr 14, 2012
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