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Please help me with this math I'm stupid

  1. Dec 16, 2014 #1
    for transformer , Zeq multiply with I .. let say the Zeq is ( 0.140 + j 0.532 ) , while I is ( 8.7 /_ -36.87 ' ) A ...... -36.87 is degree.. how to multiply these two things up? please help me . i m in urgent.. thanks.. please...
     
  2. jcsd
  3. Dec 16, 2014 #2

    SteamKing

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    Convert Zeq to polar form first.

    Since Z = x + j y, the modulus2 = x2 + y2 and the phase angle is the arctan (y / x)

    For Zeq = 0.140 + j 0.532,

    the modulus2 = 0.1402 + 0.5322 = 0.3026; modulus = 0.550
    the phase angle is then arctan (0.532 / 0.140) =arctan (3.80) = 75.26° (1st. quadrant), thus

    Zeq = 0.140 + j 0.532 = 0.550 ∠ 75.26°

    I = 8.7 ∠ -36.87°

    Zeq * I = 0.550 * 8.7 ∠ 75.26° - 36.87° = 4.785 ∠ 38.39° = 3.75 + j 2.97
     
  4. Dec 17, 2014 #3
    thanks much.. appreciate it...
     
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