60~ 



A.C. 



STARTER 



AND 



OVERLOAD 



MOTOR 

 GENERATOR 



_/'V 



EXCITER 



OVERLOAD 

 PROTECTOR 



PULSING 

 UNIT 



CONTROL AND 

 SEQUENCE SWITCH 



LOAD 



OR 

 ARRAY 



Figure 9. — Block diagram of sequential switching equipment used to supply d.c, square- 

 wave pulses. 



316 



PiGtrRE 10. — Lead-in screens and throat (arrow) of array trap. 



U.S. FISH AND WILDLIFE SERVICE 



