430 



ELECTRICAL MEASUREMENTS 



If it is desired to regulate the motor at some other speed 

 either C or M must be altered. 



To adjust the tension of the springs so that the center of gravity 

 is in the proper initial position, that is, to give a' e' its correct 

 value, it is necessary to experiment with the completed appara- 



Diagram showing Relation of 

 r to u when o'= 3 



90 91 92 co 



Angular Velocity 



870 f 880 



devolutions per Minute 



FIG. 252. Pertaining to Giebe speed regulator. 



tus. Tests show that the regulator will keep the speed constant 

 to about Ko>ooo part of its mean value. 



The Leeds and Northrup Automatic Speed Controller. The 

 constant speed necessary for driving secohmeter devices, as 

 well as sufficient energy (about 150 watts at 70 volts) for most 

 of the measurements of inductance and capacity made in an ordi- 

 nary laboratory, may be conveniently obtained by use of a device 



