Delta Connected Loads - Help Please :)

Discussion in 'Homework Help' started by ElecNerd, Jan 2, 2011.

  1. ElecNerd

    Thread Starter New Member

    Jan 2, 2011
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    Hi People, new to this so thought I would give it a go :).

    I am currently completing revision for 3 phase theory and in the process am completing some example questions. Due to lack of support/teaching from the lecturer I am having to look a majority of the info up myself...

    I am currently trying to calculate the power dissipated in one phase of a Delta connected load comprising of a resistor of 10Ω per phase and a line voltage of 650V. In addition to this I need to calculate the total power dissipated.

    Im not really looking for answers as such as thats not going to assist in the long run however I do not have even the basic calculations and formulas for this...

    Really appreciate your help people
     
  2. edgetrigger

    Member

    Dec 19, 2010
    133
    19
    In delta connection line and phase voltage are same. Just v*v/r will give you thw wattage per line. Thrice that is the total power.
     
  3. ElecNerd

    Thread Starter New Member

    Jan 2, 2011
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    0
    Hi thanks for that does that mean that the calculations are the same as that for a Star connected load then?

    Also your formula please could you clarify this for me in terms of the * you have used...sorry for the simplicity :)
     
  4. edgetrigger

    Member

    Dec 19, 2010
    133
    19
    * is multiplication symbol.

    It is not same for star connection.

    Anyways, the basics are as under

    VL is line voltage
    Vp is phase voltage

    IL is line current
    Ip is phase current

    For Star Connection

    Line current = Phase Current
    But Line Voltage VL = √3 Vp

    For Delta Connection

    Line Voltage = Phase Voltage
    But Line Current IL = √3 Ip
     
  5. ElecNerd

    Thread Starter New Member

    Jan 2, 2011
    20
    0
    Thanks a lot for your assistance. Am I right in that...

    Ip = 650/10 = 65A and therefore
    IL = 1.732 x 65A = 112.53A

    From this I have calculated the power dissipated within 1 phase (red) as...

    650 x 650 / 10 = 42250
    Therefore power dissipated in red phase = 42250W

    and 42250 x 3 = 126750W = Total power dissipated.

    Thanks alot
     
  6. edgetrigger

    Member

    Dec 19, 2010
    133
    19
    Yes, it is correct.
     
  7. ElecNerd

    Thread Starter New Member

    Jan 2, 2011
    20
    0
    Thanks a lot for all your assistance its appreciated :)
     
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