534 



ELECTRICAL EQUIPMENT 



signals such as " start," " stop," " stand-by," etc., and is con- 

 controlled from the switchboard, a whistle being used for calling 

 the operator's attention to the signals. Sometimes provision 

 is also made for answering or returning the signals to the switch- 

 board. 



Possibly the most satisfactory and most generally used signal 

 system is the individual push-button equipment, shown in Fig. 

 376. It consists of an individual stand for each machine unit with 

 the signals mounted thereon, as shown. Similar signal equip- 



I'lfi. 



FIG. 376. Individual Push-button Signal Equipment with Stand for One 



Machine. 



ments are also provided on the respective machine panels on the 

 benchboard, the two corresponding equipments being connected 

 together electrically. The signals consist of colored glass win- 

 dows with white letters illuminated by small lamps behind. Oppo- 

 site each signal is a three-way push-button switch, and a gong is 

 installed near each machine and also at the switchboard. Pushing 

 a button, for example, at the switchboard rings the gong at the 

 machine to which the signal is sent simultaneously illuminating 

 the particular signal which was sent at both places. The gong 



