286 



SYNCHRONOUS MOTORS. 



other excitations the power-factor oiily becomes fairly 

 high at the higher loads. The explanation of the curve 

 for 1'8 amps, being higher than the '9 amp. curve is to 

 be found in the greater armature waste power in the motor 

 when over-excited. 



Graphic Representation of Conditions in a Circuit Containing 

 Two Synchronous Machines. In Experiment I. it was shown 

 how to obtain the resultant voltage when two alternators 



i-o 



6. 



8 

 o 



\\l\\ 





1 



8 9 



234567 

 Lbs. pull at rim of pulley. 



Fio. 135. VARIATION OF POWER FACTOR WITH LOAD IN A 

 SYNCHRONOUS MOTOR. 

 Pulley Sin. diameter. 



differing in phase were connected to the same circuit. The 

 running of two alternators in parallel, or the connection of a 

 synchronous motor to an alternator, are special cases of the 

 problem then discussed, the only additional feature 

 introduced being that of a "current in the circuit. In 

 following discussion the voltages of the two machines will 



