326 



ELECTRICAL MEASUREMENTS 



Ryan Power Diagram Indicator. 5 The Ryan Power Dia- 

 gram Indicator is a device in which the electrostatic tube (see 

 page 647) is employed to trace diagrams, the areas of which are 

 proportional to the power supplied to the load. Its particular 

 field of usefulness is the measurement of small amounts of power 

 at high voltage. It has been applied to the measurement of 

 corona losses and to the total losses in samples of insulating 

 materials. Losses as small as 0.03 watt at 9,000 volts have been 

 measured. The accuracy of the original arrangement was about 

 5 per cent. The application of the device (sometimes called 

 the cyclograph) to the investigation of the behavior of insulating 

 materials has been developed by Minton. 6 



\\-G 



P P 



Primary of 

 Supply Transformer 



FIG. 191. Connections for Ryan power diagram indicator. 



In order to obtain the diagram, it is necessary to employ two 

 sets of electrodes. One set is arranged to deflect the fluorescent 

 spot along the X-axis on the screen; another, along the F-axis. 



Looking along the axis of the tube, the electrodes are placed 

 as shown in Fig. 191, which also shows the other connections. 



To employ this arrangement, one must be able to divide the 

 secondary of the testing transformer into two equal sections so 

 that the two condensers CC may be inserted between them. 

 The junction of the condensers is grounded. By means of the 

 electrodes, TI, the fluorescent spot is at every instant deflected 

 along one coordinate on the screen proportionally to v. The 

 electrodes, T 2 , cause the spot to be deflected along the other 

 coordinate proportionally to the instantaneous values of vi, 



