SWITCHING EQUIPMENT 



587 



attendants stand by. Extra men report to floorman or operator, 

 unless otherwise detailed. Chief and assistant chief operators 

 proceed to benchboard, maintenance men report to chief operator." 



There is another emergency whistle located on the roof of the 

 building, for the purpose of calling assistance during operating 

 emergencies and for calling the 

 operating heads and company 

 physician in case they could not 

 be located by telephone. This 

 whistle can be heard a distance 

 of five or six miles. 



A novel signal system is used 

 by the Mississippi River 'Power 

 Company in its station at Keo- 

 kuk. In general it consists of 

 transmitting and receiving dials 

 with the signal words plainly 

 marked thereon. A pointer on 

 the receiving dial is electrically 

 connected to follow the position 

 of a handle on the transmitting 

 dial. Fig. 378 illustrates a ped- 

 estal containing a transmitter 

 (lower dial) and a receiver 

 (upper dial). One pedestal is 

 located in front of each genera- 

 tor in the generator room (Fig. 

 3), and a similar equipment, 

 although without the pedestal, 

 is located on each generator 

 panel in the control room. 



A diagram of connection of 

 the apparatus, which is known 

 as position indicators, is given in 

 Fig. 379. Each complete equip- 

 ment consists, as said, of two machines, a transmitter and a re- 

 ceiver, connected as shown and resembling in design small induc- 

 tion motors. The stators are provided with an ordinary closed 

 winding, three equidistant points being permanently connected 

 together. The rotors are bipolar, connected in multiple and ener- 



FIQ. 378. Signal Equipment at 

 Mississippi River Power Com- 

 pany. Generator Room Ped- 

 estal. 



