I need help with another formula:)

Discussion in 'Homework Help' started by ESPguitar, Aug 26, 2005.

  1. ESPguitar

    Thread Starter Member

    May 15, 2005
    16
    0
    Hi again;)

    If i have 3 elements, each rated at 200W, 500W and 800W, how do i calculate the total power for these three elements?

    Thanks,

    Robin:)
     
  2. ESPguitar

    Thread Starter Member

    May 15, 2005
    16
    0
    I forgot to ask if it is the same formulas for power as for resistors?

    Since heating elements is resistors..

    Thanks,

    Robin
     
  3. string

    New Member

    Aug 26, 2005
    1
    0
    hey man,if all the elements are resistors ,then u can add all the powers.

    But if there is any presence of reactive elements then u need to find the resultant of resistive and reactive powers to get the total power,

    suppose total resistive power=P

    and total reactive power=Q

    then the resultant power is reprsented by P+jQ


    its magnitude is √ (P square+Q square)
     
  4. ESPguitar

    Thread Starter Member

    May 15, 2005
    16
    0
    Ok, thanks string;)

    But what about the total power if i just get this information:

    Three heating elements is connected in paralell, the voltage is 230V and the elements have this ratings:

    P1=200W
    P2=500W
    P3=800W

    Is the total power of this 1500W? Or do i have to calculate how much resistance each elemt have and work from there?

    Thanks guys:)

    Robin
     
  5. pebe

    AAC Fanatic!

    Oct 11, 2004
    628
    3
    As the devices are specifically heating elements, reactance will be negligable. So just add the individual powers. Your assumption of 1500W is correct.
     
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