262 



ALTERNATORS. 



be modified somewhat from those given above. Since it 

 may be necessary to run any machine with any other, or 

 with several other machines, a simple means must be pro- 

 vided whereby the low-pressure winding of the synchronising 

 transformer of any machine may be readily connected to 

 that of any other. The usual method adopted is to have 

 synchronising bus bars extending across the back of all the 

 generator switch-board panels, as shown in Fig. 125 where 



MAIN BUS- BARS 



FIG. 125. CONNECTIONS FOR SYNCHRONISING ALTERNATORS. 



G lt G z represent the armatures of two of the machines, of 

 which there may be any number connected to the switch- 

 board in a similar manner. 



The letters given on the diagram, Fig. 125, have the 

 following meaning : . 



Alternator armature. 



S S Main 2-pole switch. 



A Alternator ammeter. 



V Alternator voltmeter. 



S T Synchronising transformer. 



L Synchronising lamp. 



L S Synchronising lamp switch. 



It will be noticed that the generator voltmeter is shown 

 connected to the secondary of the synchroniser transformer. 



