1074 THE BELL SYSTEM TECHNICAL JOURNAL, OCTOBER 1951 



battery is floated at 13 volts and a discharge resistor in each fused discharge 

 lead is adjusted during installation to drop the voltage to the normal limits 

 of 11.0 zb 0.1 volts at the radio bays. Under 60-cycle a-c. power failure condi- 

 tions before the gas engine or diesel alternator accepts the a-c. load, the 

 radio bays may operate between their emergency limits of 9.9 to 11.5 volts. 



Fig. 23-i2V and 24V power plant. 



Figure 23 illustrates the installation in a t)^ical tower of the —12 volt 

 supply required for a main route of six radio channels in each direction. 



B. +J30 Volt Supply 



The 130-volt plate supply consists of a 63-cell storage battery which is 

 charged and floated by two to eight 8-ampere regulated tube rectifiers. As 



