ELECTRICAL EQUIPMENT - Q.3 Batteries  overcharging  and  Ammeter  indicates  high or full output all the time. Check    regulator    positive    sensing    lead    and    its connection at regulator. If no fault, regulator is faulty. 5. Fault Finding on 11 AC If the alternator does not produce its rated output of 43  amps  for  12  volt  and  23  amps  for  24  volt  circuit,  the failure  may  be  due  to  any  unit  or  the  associated  wiring, and the following procedure should be followed. TEST 1. Check the Field Isolating Relay Disconnect   the   earthed   battery   terminal   and   the cable    from    the    alternator    main    output    terminal. Connect  a  0-60  DC  ammeter  between  the  terminal and disconnected cable.  Link terminals 'C1' and 'C2' on   the   field   relay.      Reconnect   the   battery   cable. Close the master switch and start engine and run at charging  speed.    If  ammeter  shows  a  charge  the relay is faulty.  or its wiring and connections. If ammeter shows no charge, carry on with Test 2. TEST 2 Check the Alternator and Control Box Leave  the  test  ammeter  connected,  and  disconnect cables   'F'   and   '-'   from   control   unit   and   join   them together.  Remove link from field relay terminals and ensure  they  are  connected  to  'C1'  and  'C2'.    Start engine and run at charging speed. Ammeter  should  indicate  current  values  of  35  amps or more for 12 volt circuit or 22 amps or more for 24 volt  circuit.    A  zero  or  low  reading  indicates  a  faulty alternator. If satisfactory output is recorded, a faulty control unit is indicated. TEST 3 Checking or Adjusting the Voltage Setting The regulator of the 4 TR control unit must be set on CLOSED   CIRCUIT,   when   the   alternator   is   under load.    Also,  the  system  must  be  stabilized  before checking  or  resetting  is  carried  out,  and  the  battery must   be   in   a   well   charged   condition.      Check   the battery   to   control   unit   wiring,   to   ensure   that   the resistance  of  the  complete  circuit  does  not  exceed 0.1  ohm.    Any  high  resistance  must  be  traced  and remedied.  Connect a test DC voltmeter (suppressed zero  type)  scale  12-15  volts  for  12  volt  installations or  24-30  volts  for  24  volt  installations,  between  the battery   terminals,   and   note   the   reading   with   no electrical  load.    Disconnect  battery  earth  cable  and connect    test    ammeter    between    alternator    main terminal and disconnected cable.  Reconnect battery earth   cable,   and   switch   on   an   electrical   load   of approximately  two  amps.    Start  engine  and  run  at about 2000 rev/min, for at least eight minutes.  If the charging   current   is   still   greater   than   ten   amps, continue  to  run  engine  until  this  figure  is  reached. Then    compare    the    volt    meter    reading    with    the appropriate    setting    limits,    as    specified    for    the particular control unit as follows. 12 V (37423)/(37449) 13.9 14.3 volts 24 V (37444)'(37502) 27 9 28.3 volts 12 V 37429 13.7 14.1 volts (Part   no.   marked   on   upper   edge   of   the   moulded cover of Control Unit). If    reading    obtained    is    stable    hut    outside    the appropriate    limits    the    unit    can    be    adjusted    as follows. ADJUSTMENT OF VOLTAGE SETTING Stop the engine and remove the control unit from its mounting..      At   the   back   of   the   unit   is   a   sealed potentiometer  adjuster.    Carefully  scrape  away  the sealing compound.  Then start the engine, and while running  the  alternator  at  charging  speed,  turn  the adjuster   slot   —   CLOCKWISE   to   INCREASE   the setting  or  ANTI-CLOCKWISE  to  DECREASE  it  — until the required setting is obtained. Recheck   the   setting   by   stopping   the   engine,   then start again and slowly "run-up"  to charging speed.  If setting   is   now   correct,   remount   the   control   unit, disconnect   test   meters   and   restore   original   wiring connections.        If,    after    adjustment,    the    voltmeter reading   remains   unchanged,   or   increases   in   an uncontrolled  manner,  then  the  control  unit  is  faulty and a replacement must be fitted.