the succeeding sections are below it. When the section having the lowest 

 value of resistors has been removed from the holder (in the desired cali- 

 bration increments) , the other gage sections in the holder should be 

 removed and a succeeding section put in the bottom; thus, all sections 

 having the lowest resistors will be removed from inside the gage mount 

 in succession during the calibration process. 



Calibration of the gage proceeds as follows: 



a) If a magnetic tape recorder is used, calibrate it with the 

 strip-chart recorder as outlined on page 93. 



b) Remove the epoxy gage sections from the gage mount. 



c) Set the a.c. voltage-adjust control (autotrans former) on the 

 voltage-control, rectifier-filter, programmer unit to its 

 counterclockwise position. 



d) Apply power to the gage system and turn on the strip-chart 

 recorder. 



e) Using the mechanical adjusting lever on the strip-chart recorder 

 penmotor, adjust the .recording pen to the left side of the 

 recording chart. 



f) Place all epoxy gage sections under water. The sections should 

 be placed adjacent to the metal gage holder with the lead contact 

 tips near the ground rod. The spacing between the tips and the 

 ground rod should be nearly the same as that provided when the 

 sections are inside the gage holder. 



g) Adjust the a.c. voltage control clockwise to provide full-scale 

 movement of the strip-chart recorder pen. 



h) Repeat steps b, e, f, and g until zero and full scale are stable. 



i) Remove the top epoxy gage section from the water 1 foot at a 

 time, and mark the strip-chart recording accordingly. Continue 

 with the remaining gage sections. This is the calibration for 

 the wave gage. If the calibration is nonlinear, clean the lead 

 contact tips on the gage sections, check the electrical con- 

 nections of the epoxy gage cables and the connection to the 

 ground rod, and recalibrate. 



j) Mount the transformer unit near the top of the gage holder. 



k) Adjust the programmer to provide the desired recording periods 

 of the wave gage. The programmer may be set to provide a re- 

 cording beginning any hour for a selected number of minutes. 

 Hours may be skipped by proper installation of the knurled 

 screws in the programmer dial . 



43 



