A  description  of  the  circuits  follows :  The  apparatus  of  the  power  set  is  represented  by  the
alternator  armature  A,  C,  the  primary  winding  of  the  closed  core  transformer  P,  the  circuit
including  the  wattmeter  W.  The  secondary  circuit  comprises  the  secondary  winding  of  the
transformer  S,  the  high  potential  condenser  C-l,  spark  gap  G  and  the  primary  winding  of  the
oscillation  transformer  P-l.  The  aerial  circuit  is  represented  by  the  secondary  winding  S-l,
the  short  wave  condenser  C-2  and  the  aerial  tuning  inductance  S-2.
The  circuit  of  the  emergency  induction  coil  extends  from  the  D.  C.  switch  at  the  left  of
the  drawing,  though  the  underload  circuit  breaker  B,  through  the  regulating  resistance  R,  to
a  24-30-volt  storage  battery  shunted  by  a  small  voltmeter  V.  The  charging  resistance  R  is
proportioned  to  pass  from  6  to  7  amperes  through  the  storage  battery  during  the  charging
process.  The  function  of  the  underload  circuit  breaker  has  been  described  in  Part  V,  and
it  is  sufficient  to  say  here  that  it  automatically  opens  the  circuit  in  case  the  voltage  of  the
generator  falls  below  that  of  the  storage  battery.
E4YOLT  STORAGE
BATTERY


&  V.  6V.
Fig.    204 — "Plain    Aerial"    Emergency    Transmitter.
(a)  Adjustment  and  Tuning  of  the  Set.  To  place  the  storage  battery  on
charge,  the  D.  C.  switch  is  closed  and  the  plunger  U  of  the  underload  circuit
breaker  pushed  upward  by  hand,  the  charging  circuit  thereby  being  closed  through
the  contact  points  E,  E.
