TM 10-3930-671-24 FIGURE NO.  17. TABLE 2. ALTERNATOR  OUTPUT  AND  SYSTEM  TEST  -  This  test  will  determine  if  the  alternator  is  capable  of  producing  a minimum rated output.  The charging circuit is also tested under partial load to determine if there is excessive voltage loss between  the  alternator  and  battery.    The  test  ammeter  remains  connected  in  series  with  alternator  output  to  battery. Carbon  pile,  with  load  control  knob  turned  off,  is  connected  across  the  battery.    Connect  voltmeter,  negative  lead  to alternator ground terminal, positive lead to alternator output terminal (Figure No.  17). Start engine and run at 700 to 1000 rpm.  Slowly apply carbon pile load until alternator produces 10 ampere output.  Let engine operate in this manner for 5 minutes to stabilize component temperature.  Increase engine speed to provide 3000 to  4000  alternator  rpm.    Repair  punctured  insulation  with  tape.    Regulator  may  require  replacement,  if  circuit  inspection fails to locate difficulty.  A low voltage reading would indicate a defective voltage regulator.  Remove or switch out 1/4 ohm resistor immediately after test.  Reconnect output lead to alternator output terminal. Increase  carbon  pile  load  on  the  battery  so  alternator  will  develop  its’  minimum  rated  output,  indicated  in  Table  No.    2. Voltage  must  remain  between  13.0  -  15.0  volts.    If  minimum  rated  output  cannot  be  reached,  the  alternator  will  require disassembly and repairs. System voltage loss, due to loose connections, etc., is determined while the alternator is producing 10 ampere output.  The voltage measured across the battery should be within 0.3 volts of voltage measured from the alterna- tor output and ground terminals.  Turn carbon pile control knob off after test to avoid discharging battery. Make necessary repairs to insulated or ground circuit to correct any deficiency. F-284