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Homework Help: Alternating current

  1. Jul 5, 2009 #1
    1. The problem statement, all variables and given/known data

    in figure shown below, a lamp load taking 6A and a single-phase motor taking 4A from 120v/60Hz source. the current to the lamp load is in phase with the voltage and the current to the motor logs 50 degrees. determine:
    a) value of total current IT (rms)
    b)angle by which current logs 6A
    c)angle by which total logs voltage

    2. Relevant equations

    iT = i1+ i2

    3. The attempt at a solution

    iT = i1+ i2

    i am confused on how they get this

    iT =8.49(sin wt cos 40 - cos wt sin 40)+ 5.66(sinwt cos 90 - cos wt sin 90)

    please help ...tnx!!!

    Attached Files:

    • img.doc
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  2. jcsd
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