376 Report S.A.A. Advancement of Science. 



for, as we increase the losses in the four mains 1.5 fold, by super- 

 posing a single phase current of half the power, this same total loss 

 would be caused by an increase in the two phase current of a pure 

 two phase system equal to 



times the original current. Consequently, we can transmit 



I. - V 17 



1-5 



■^ X 100, 



or 23 per cent, more power with the polycyclic system. 



A three phase single phase system is not so advantageous, and 

 the saving is only about 6 per cent, instead of 23, so that it would 

 seem advisable to convert a three phase current into a two phase 

 current before distribution by means of the well known Scott system. 

 This has been done in Fig, 20. For, since a three phase, three wire 

 system requires a quantity of copper equal to 75 per cent, of that 

 wanted for a single phase plant, all conditions being equal, the 

 saving in material is 



100 = 60/0, 



assuming that the superposed power is equal to half the three phase 

 power. 



Advantages of a Polycyclic System. 



1. The desired frequencies for lighting and power circuits are 

 obtained. 



2. The regulation of the lighting pressure is simple. 



3. The P.D. for motor circuits is raised, and copper is 

 therefore saved. 



4. The power transmitted with a polycyclic system over mains 

 with a given cross-section is greater than that from a pure single 

 phase plant. 



The advantages which the inventors Arnold-Bragstad-La Cour 

 claim for their system, have been confirmed by a series of tests by 

 Dr. F. Marguerre. * 



See " Experimentelle Untersuchtingen am Polycyklischen Strotnvertetlungs system 

 Arnold-Bragstad-La Cour." F. Enke, Stuttgart. 



