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  1. S

    Ripple factor & Complex Imag. 1-75

    Complex Imaginary Vol I problem 75 asks to find the ripple factor of a 3 phase DC rectifier. The formula they use for the solution is r = (Vrms/Vavg) * 100 (actually, they write Vac for Vrms and Vdc for Vavg) for a ripple factor of 103%. But I thought ripple factor r = sqrt((Vrms/Vavg)2-1) *...
  2. S

    NCEES #129

    Digging this topic back up, because I still can't make sense of these! For 129, the method posted above with Ze=R*pf + X*[sin(arccos(0.8))] I can understand, but then isn't the Ze=0.0232+j 0.0288? Not seeing how to get 0.052 Ohm-N... Also the NEC and previous poster note that the R and X...
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    Current Transformer

    If I understand right, the sqrt(3) for the secondary isn't necessarily for the 30 deg shift, but it's because the secondary CT's are in a delta configuration. The fact that the CT's are wye-delta accounts for the 30 deg shift. This is an interesting problem, is it out of a particular book?
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