over   speed   protection   device   actuates,   read   and   record all   instrument   readings   just   prior   to   the   point   of actuation  and  note  on  the  data  sheet  that  the  protection device    actuated. NOTE This   step   is   not   applicable   to   generator sets   having   governors   that   utilize   a threaded  shaft  and  lock  nut(s)  or  other mechanical  means  as  a  method  of operator   speed   adjustment. (h)   Adjust   the   generator   set   frequency   for the  minimum  attainable  frequency.  Read  and  record all   instrument   readings. NOTE This   step   is   not   applicable   to   generator sets   having   governors   that   utilize   a threaded  shaft  and  lock  nut(s)  or  other mechanical  means  as  a  method  of operator   speed   adjustment. (i)  Repeat  16-16c.  (1)  and  16-16c.  (2)(a) through  (f)  for  each  frequency. d.   Results.   The   data   sheet   shall   show   the   maxi- mum   and   minimum   frequencies   attained   at   rated   load, the   maximum   and   minimum   attainable   frequencies   at no  load  and  actuation  of  the  protection  devices  (if applicable).   Compare   these   results   with   the   require- ments  of  Table  16-1. 16-17.   Overspeed   Protective   Device   Test. a.   General.   To   assure   that   adequate   protection is   afforded   the   generator   set   against   overspending, the   overspeed   protective   device   must   operate   properly. b.   Apparatus.   A   frequency   meter   or   tachometer as   described   and   illustrated   in   MIL-HDBK-705, Methods   104.1   or   109.1   shall   be   required. c.   Procedure. (1)   Preparation   for   test.   Connect   the   frequency meter   in   accordance   with   the   applicable   figure   of MIL-HDBK-705,   Method   205.   l,   Paragraph   205.   1.9, or   utilize   the   tachometer   in   accordance   with   the   man- ufacturer’s   instructions.   Electronic   governor   and throttle   stops   must   be   deactivated. (2)   Test. (a)   Start   and   operate   the   generator   set   at rated  speed  (frequency),  rated  voltage  and  no  load. (b)  Slowly  increase  the  engine  speed  until the   overspeed   protective   device   actuates.   Record the  speed  of  the  generator  set  at  this  point,  and  the malfunction   indicator   light   indication. CAUTION Do  not  operate  the  set  in  excess  of  125 percent   of   rated   speed   or   as   otherwise limited   in   the   procurement   document. (c)  Attempt  to  start  the  set.  Record  if starting  is  achieved. If   the   set   did   not   start,   reset the   overspeed   protective   device. (d)  Repeat  steps  (a)  through  (c)  above  two additional   times. d.  Compare  the  test  results  with  requirement  of Table   16-1. 16-18.   Circuit   Interrupter   Test   (Short   Circuit). a.   General.   A   circuit   interrupter   is   connected between   the   generator   voltage   reconnection   system and   the   generator   set   output   terminals   to   disconnect the  generator  output  from  the  load  and  also  to  protect the   generator   from   a   short   circuit.   The   circuit   inter- rupter  is  operated  from  a  current  sensor  external to   the   interrupter. b.  Apparatus.  Instrumentation  for  measuring load   conditions   shall   be   as   described   and   illustrated in   MIL-HDBK-705.   In   addition,   a   non-inductive shunt,   as   short-circuiting   switch,   galvanometers mat  thing  net  works,  an  oscillograph  as  described  and illustrated   in   MIL-HDBK-705,   Method   106.1,   para- graph  106.  1.3  and  galvanometers  having  a  flat frequency  response  (flat  within  plus  or  minus  five percent)  from  DC  to  3,000  hertz  will  be  required. c.   Procedure. (1)   Preparation   for   test. (a)   Connect   the   load   and   instrumentation   in accordance  with  the  applicable  figure  of  MIL-HDBK- 705,  Method  205.  1,  paragraph  205.  1.  10  for  one voltage   and   frequency. (b)   Connect   the   shunt,   galvanometers matching   net   work,   oscillograph,   and   short-circuiting switch   as   illustrated   in   figure   512.   1.I. (2)   Test. (a)   Start   and   operate   the   generator   set   at rated   voltage,   rated   frequency   and   rated   load. (b)   Set   the   oscillograph   time   marker   to   a minimum  of  0.  01  seconds  or  use  a  60  hertz  timing trace   set   the   chart   speed   such   that   the   individual peaks   of   the   current   waveform   are   clearly   visible and   adjust   the   peak   -to-peak   rated   current   amplitude to  a  minimum  of  0.5  inch  (or  approximately  12 millimeters). 16-9