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BELL SYSTEM TECHNICAL JOURNAL 



For one of the larger motor-generator sets the cost of the first set, 

 including a filter, is about the same as that of the former "telephone 

 generator" type outfit. The cost of the additional sets used in the 

 power plant, which under present conditions are not provided with 

 individual filters if a common filter is placed in the talking discharge 

 circuit, is about half that of the present type sets. 



Power Factor Correction 

 In connection with the new generators, synchronous motors are 

 being made available for use where it is desired to improve the power 

 factor of the load. The synchronous motors will be arranged to give 



Fig. 6 — Generator end of control switchboard, as provided five years ago, rear view. 

 Six 1,000- and 1,500-ampere generators, bus bars terminated for growth when addi- 

 tional units required. 



0.8 leading power factor, so all motors in the plant will not need to be of 

 this type. The standard induction motors which are cheaper will be 

 retained, both types thus being available to meet all conditions. For 

 existing installations requiring a moderate amount of correction to 

 avoid the imposition of penalties and where no new motor-generator 

 sets are to be added, static condensers are available to improve the 

 power factor and thereby reduce the excess charges on the power bill. 



