TM 5-6115-593-12 TO 35C2-3-463-1 low   and   deenergizes   when   it   does. Contacts    7    and    8    of    K11    open deenergizing the CB2 trip coil which in turn,  disconnects  the  generator  from the     load.     Simultaneous     with     this action,   K11   contacts   3   and   4   close activating relay K33 and UNDERVOLTAGE indicator lamp DS33.  A false undervoltage condition will,  of  course,  exist  while  the  engine is  shut  down  or  is  in  the  process  of picking   up   speed.      To   prevent   the needless   disconnecting   of   generator G1,  relay  K11  contacts  3  and  4  have been   placed   in   series   with   normally open contacts 7 and 9 of K52.  Relay K52    will    not    energize    until    engine speed  is  in  excess  of  1200  rpm  and speed switch SS2 closes. (3) Reverse Power Protection. While in a parallel mode of operation, an out-of- phase   or   an   undervoltage   situation could     cause     the     current     of     one generator to feed the second generator.      Such   a   condition   might either  burn  out  the  second  generator or  cause  it  to  "motor"  (the  generator functions    as    motor).        Relay    K112 activates    upon    sensing    a    reverse- power condition and through its normally    open    contacts    3    and    5, energizes  K34  and  lights  REVERSE POWER indicator lamp DS34.  Relay K34     normally     closed     contacts,     in series with the generator circuit breaker     control     circuit,     open     and subsequently disconnect the generator from the main buss. (4) Overload   Protection.      If   the   output current  of  any  phase  winding  of  G1 exceeds an amount that might possibly  be  harmful  to  the  generator, thermal    relay    K114,    after    a    short period of time, activates. Consequently, relay K35 and indicator lamp DS35 both energize, and normally closed contacts of K34 open to interrupt the generator circuit breaker   control   circuit.      As   before, when this occurs, the generator output is immediately disconnected from the main  buss.    Generator  G1  is  capable of safe operation while overloaded for short  periods  of  time.    This  accounts for the delayed operation of K114. (5) Short Circuit Protection.  In the event of  a  short  circuit,  the  generator  must be immediately disconnected from the load.        Relay    K113,    upon    sensing excessive   current,   will   energize   and close its contacts 7 and 8; then, relay K36  and  short  circuit  indicator  lamp DS36  will  energize.    Normally  closed contacts   of   K36,   in   series   with   the generator circuit breaker control circuit,   open   and   consequently   CB2 disconnects   the   generator   from   the main buss. (6) Generator     Output     Monitoring.     The voltage,    current,    frequency,    power, KVAR, and power factor of the output must    be    continually    monitored    to ensure  proper  use  of  the  generator. The voltage and current are measured    by    voltmeter    M101    and ammeter    M102    and    switched,    as required, by S101 and S102 respectively from one generator winding  to  another.  Output  frequency is monitored by a circuit consisting of A103 and M103.  A103 is a frequency converter   which   produces   a   voltage analog  of  the  output  frequency.    This voltage  is  applied  to  and  metered  by M103     which     indicates     the     output frequency in Hertz.  Power (kilowatts) and KVAR (kilovolts-amperes reactive) are measured by KW meter M107    and    KVAR    meter    M108    in conjunction with converters A107 and A108,   respectively.   A107   and   A108 convert   current   and   voltage   into   an output 1-29