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Mixed Resistive Inductive load

  1. Nov 11, 2013 #1
    hello

    i do have something unclear about =..

    POWER Real Power Reactive Power Inductive Load
    500 511 W 329VAR 1.2
    400 519W 312VAR 2.0L
    300 490W 382VAR 3.2L

    IS ABOUT MIXED RESISTIVE INDUCTIVE LOAD..

    MY THOUGHT OF THIS IS THAT… THE PURPOSE OF THE INDUCTIVE IS TO STORE ENERGY..
    BUT WHEN THE POWER IS 500, MY REAL POWER IS 511 AND REACTIVE POWER IS 329.. BUT THE INDUCTIVE LOAD IS 1.2.. SO AM I RIGHT TO SAY THAT THE LOWER INDUCTIVE AND HIGHER THE REAL POWER???

    I WOULD LIKE TO KNOW WHAT CAUSE THE CHANGE AND HOW DOES IT EFFECT???
     
  2. jcsd
  3. Nov 12, 2013 #2

    NascentOxygen

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    Staff: Mentor

    Where did you get that set of numbers from?

    What does the L signify in 2.0L ?
     
  4. Nov 12, 2013 #3
    The L is Henries I would assume and is the example induction for the 1st and 3rd columns The first column is probably "apparent power" for mixed circuits. The 2nd column is for resistive only circuits. 3rd column is for reactive only circuits. Just my educated guess but I'm a newby to this stuff.

    Real power is resistive circuits only from just reading about it here:
    https://en.wikipedia.org/wiki/AC_power

    I could be wrong about that first column meaning apparent power.
     
  5. Nov 12, 2013 #4
    It looks to me (again I'm a noob) that the higher the inductionthen the higher the reactive power (obviously) and thus lower Real power. So I believe you are correct when you say the lower the inductive load the higher the real (resistive) power. I would assume it's something to do with the phase offsets of voltage vs current via the inductive portion that causes this effect.
     
  6. Nov 12, 2013 #5
    When R = 0 you have 90 degree current lag due to induction. As the resistance increases, the 90 degree current lag due to induction decreases towards non lag.
     
  7. Nov 13, 2013 #6
    Thanks for the reply gents,

    But what is the purpose of having inductance to it?? How does it effect...

    Cos the voltage input is 380, the resistive load is 300w and inductance is 3.2L.
    The output of real power is 490w and reactive is 382var... How does it effect each other....????
     
  8. Nov 15, 2013 #7

    NascentOxygen

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    Staff: Mentor

    Some inductance in the load is unavoidable, it's a consequence of using wires to create electromagnets in devices such as solenoids, transformers, and motors, and of using wires as long power transmissions lines. Everything made using coils of wire has inductance, and it's inescapable.

    As for explaining your set of numbers, I'm still waiting for my question to be answered:
     
  9. Nov 19, 2013 #8
    is a experiment that i need to do..
     
  10. Nov 19, 2013 #9
    In testing - high inductance allow you to test at full voltage, AND full current - but at very low power.

    For example - you could conceivably test a 100KW system that is 90% Eff, with only a 10KW supply - granted there are some REAL losses in the inductor.
     
  11. Nov 22, 2013 #10
    let take take voltage is 380v
    line length is 150km
    active power consume is 300w

    output after setting up

    voltage: 377
    current (line end) ; 0.45
    reactive power: 35
    power factor :0.99
    current (line start); 0.44
    active power :303
    reactive power (line start); -31

    i still unclear about the result
     
  12. Nov 23, 2013 #11

    NascentOxygen

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    Staff: Mentor

    Where did you get these figures from? What is the exact question associated with them?
     
  13. Nov 23, 2013 #12
    It does not seem that your data "adds up" - 1Ph or 3 Ph?

    Active (real ) power 300W? 300W/(377V * Sqrt 3) = I line .459A..... that is just the current due to the REAL power - etc

    Also -- 150kM line will often be capacitive but the load at the end is inductive. ( I believe that is the root issue you are looking for)

    Also -- if you are looking for an accurate formula - include the units - when the units are applied in the mathematical formula you will often find the errors because the units come out wrong.
     
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