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  VIII. 
  Theory 
  of 
  the 
  Alternate 
  Current 
  Generator. 
  By 
  

   Thomas 
  R. 
  Lyle, 
  M.A.., 
  Sc.D., 
  Professor 
  of 
  Xatural 
  

   Philosophy 
  in 
  the 
  University 
  of 
  Melbourne 
  *. 
  

  

  IT 
  has 
  been 
  usual 
  hitherto 
  to 
  ascribe 
  the 
  distortion 
  of 
  the 
  

   wave-form 
  of 
  the 
  current 
  given 
  by 
  an 
  alternate 
  current- 
  

   generator 
  to 
  ; 
  — 
  

  

  1. 
  " 
  Lack 
  of 
  uniformity 
  and 
  pulsation 
  of 
  the 
  magnetic 
  

  

  field, 
  causing 
  a 
  distortion 
  of 
  the 
  induced 
  e.m.f. 
  at 
  

   open 
  circuit 
  as 
  well 
  as 
  under 
  load/^ 
  

  

  2. 
  " 
  Pulsation 
  of 
  the 
  reactance 
  causing 
  higher 
  harmonics 
  

  

  under 
  load/^ 
  

  

  3. 
  " 
  Pulsation 
  of 
  the 
  resistance 
  causing 
  higher 
  harmonics 
  

  

  under 
  load 
  also 
  " 
  t« 
  

   And, 
  as 
  far 
  as 
  I 
  have 
  been 
  able 
  to 
  find 
  out, 
  another 
  cause 
  has 
  

   been 
  overlooked, 
  namely, 
  the 
  mutual 
  reactions 
  between 
  

   armature 
  and 
  field, 
  which 
  when 
  tlie 
  generator 
  is 
  loaded 
  is 
  

   at 
  least 
  as 
  important 
  as 
  any 
  of 
  the 
  foregoing. 
  

  

  If 
  such 
  is 
  the 
  case 
  it 
  can 
  only 
  be 
  explained 
  by 
  the 
  fact 
  that 
  

   the 
  theory 
  of 
  the 
  simple 
  alternator 
  has 
  not 
  been 
  completely 
  

   worked 
  out. 
  

  

  In 
  the 
  following 
  paper 
  this 
  is 
  done 
  for 
  an 
  alternator 
  with 
  

   a 
  uniform 
  field 
  by 
  means 
  of 
  a 
  new 
  application 
  of 
  the 
  vector 
  

   method 
  in 
  which 
  all 
  the 
  harmonics 
  of 
  a 
  periodic 
  function 
  are 
  

   dealt 
  with 
  simultaneously. 
  

  

  In 
  the 
  same 
  is 
  shown 
  how 
  to 
  take 
  account 
  of 
  hysteresis 
  

   and 
  eddy 
  currents, 
  and 
  the 
  theory 
  of 
  the 
  action 
  of 
  dampers 
  

   in 
  reducing 
  the 
  heating 
  in 
  the 
  field 
  is 
  also 
  given. 
  

  

  The 
  theory 
  of 
  the 
  alternate 
  current 
  synchronous 
  motor 
  is 
  

   also 
  dealt 
  with. 
  

  

  Fig. 
  1. 
  

  

  1. 
  Let 
  two 
  coils 
  be 
  arranged 
  as 
  indicated 
  in 
  fig. 
  1, 
  one 
  of 
  

   them, 
  F, 
  called 
  the 
  field 
  coil, 
  being 
  fixed 
  and 
  having 
  a 
  battery 
  

   of 
  constant 
  e.m.f. 
  = 
  77 
  in 
  its 
  circuit, 
  the 
  other^ 
  A^ 
  called 
  the 
  

  

  * 
  Communicated 
  by 
  the 
  Physical 
  Society 
  : 
  read 
  April 
  23, 
  1009. 
  

   t 
  Steinmetz, 
  * 
  Alternating 
  Current 
  Phenomena.' 
  

  

  