Energy Storage 



Although the principle of energy storage is as old as 

 the electrical industry, great advances have recently been 

 made in the construction of energy storage capacitors, 

 largely as a result of atomic power developments. The type 

 of job to be done will dictate whether to use very low capa- 

 city at high voltage, or very large capacity at lower voltage. 

 The basic formula for energy storage is: 



E = CV^ 



In most of the experiments reported here, very large 

 capacitors were used at moderately high voltages, for exam- 

 ple 60 microfarads at a working voltage of 15, 000. Most 

 early work used 100 or more microfarads at 4000 working 

 volts. Corona discharge causes little trouble at these 

 voltages but can be severe at higher voltages, particularly 

 in the damp atmosphere at sea. 



Few experimenters have made any mention of the 

 inductance of energy storage capacitors. It is important 

 to keep this value low for efficient operation. Only recent 

 designs have this feature. It is equally important to keep 

 all the "tank circuit" leads of heavy copper bus, since the 

 discharge currents run into many thousands of amperes. 



Dielectric Ma terial for the Gap 



For many years there has been a continuing search for 

 a suitable dielectric material that could withstand the explo- 

 sive forces at the point of discharge. A number of materials 

 have been found that are fairly satisfactory for energy levels 

 up to about 1000 watt-seconds, at 1 atmosphere of pressure. 

 Pressure increased beyond that level resulted in water 

 getting inside the gap and causing internal explosion. Many 

 materials were found that could withstand severe beating 

 with a hammer without breaking or chipping but fractured 

 when used in the gap. A certain amount of pliability seems 

 desirable and also reduces the problem of recoil which is 

 very great in the underwater spark explosion. Additional 

 evidence of the tremendous forces at the gap is that the 

 shock wave generated can be used to form metals such as 

 stainless steel, titanium, etc. Numerous combinations of 



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