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Dude99

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About Dude99

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    EE
  1. The wording is important FAULT power...NOT total input power obviously the xfmr has losses but input P = fault + losses output = fault therefore the FAULT P component is the same on both sides but total in vs out is not another take: inf bus Z source = 0, ie, no Vdrop input P=1/pu Z, no drop means output P =1/pu Z AVAILABLE the losses are still fault P supplied by the source, even if the bolted fault Z=0 meaning all fault P is dissipated in the xfmr itself
  2. Most texts on transients have a chapter on lightning, most common cause of outages This is the one I used class was taught by a guy taught by the author for the price a must have imho https://m.alibris.com/search/books/isbn/9780471620587?ds_rl=1264488&ds_rl=1264488&gclid=EAIaIQobChMI7ISa2MTP5wIVj5OzCh3EHw_8EAQYBCABEgLXAPD_BwE&gclsrc=aw.ds&utm_campaign=NMPi_Smart_Shopping&utm_medium=cpc&utm_source=Google&utm_term=NMPi_Smart_Shopping
  3. Most texts on transients have a chapter on lightning, most common cause of outages
  4. Lethality has 2 factors Duration/time and i magnitude i = 175/(sqrt t) i mA, t in sec, , 175 is avg wt in lbs look up Dalziel (invented the gfci), an EE prof at ucla iirc a static charge is uSec so a higher i can be tolerated, TC ~ RC, typ body R 600-1200 Ohm, very little C
  5. NGR's are required by law in mining to limit frame V to <40 An add on ? what is the N-G V of the ungrounded phases during a gnd fault? hint: what is the N V elevated to?
  6. B during + swing 2 x sqrt2/Pi x 240/20 x 10 = 108 during - swing RL shunted so RL sees no i so V = 0 avg = 54
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