TM 10-3930-671-24 45 Amp System with Regulator FIGURE NO. 5.1 The  lamp  driver  function  works  off  AC  taps.    The  lamp turns  off  at  a  voltage  >  9  volts.    When  AC  tap  potential drops  below  6  volts  the  lamp  turns  back  on  (FIGURE NO.  5.2). When the ignition switch is "on" and the alternator is not spinning,    the    indicator    lamp    will    be    "on".    With    the alternator spinning, the regulator turns Non" at approximately    800-1000    RPM    (rotor    RPM)    and    AC voltage  generated  in  stator  windings  is  amplified  by  the turn-on   circuit   in   voltage   regulator.   Once   this   point   is reached, the power transistor is turned "on", allowing the rotor to be magnetized (Full Field).  When this condition is  reached,  the  alternator  starts  to  charge  (Rotor  speed reaches  approximately  1700  RPM).    The  lamp  will  turn "off" when a voltage at the AC Tap is > to 9 volts. System voltage is at 14.3 + .2 volts. FIGURE NO. 5.2 ZENER  DIODE  -  The  Zener  diode  is  a  rather  unique diode; the ability to pass current in the forward bias mode of the Zener diode is similar to the "normal" characteristics  of  an  ordinary  diode.    However,  in  the reverse bias direction, the Zener diode has the ability at a   predetermined   voltage   to   literally   "destroy"   its’   high reverse  bias  characteristic,  thus  allowing  current  to  flow through it. FIGURE NO.  6 The   above   may   be   seen   more   clearly   by   observing Figure No.  6.  Figure No.  6 shows the typical operating characteristics  of  a  1  O0V  Zener  diode.    This  can  be seen when starting at the zero bias point and moving to the    right,    or    in    to    the    forward    bias    area.        Almost immediately, the diode allows current to flow, identical to the operational characteristic of a "normal" diode.  Now, F-273