THE TRANSFOBMEE. 



149 



By making a series of such observations, and plotting the 

 results on a curve, as shown in Fig. 68, it will be found that at 

 low frequencies the effects of the eddy currents are hardly 

 seen, and loss and frequency are proportional, i.e., the curve 

 is straight. If there were no eddy current losses the curve 



400 800 1200 1600 



Revolutions pep minute of 4-pole alternator. 

 FIG. 68. SEPARATION OF IRON LOSSES IN TRANSFORMER. 



would continue straight, i.e., along the line M, which is 

 drawn as a tangent to the lower part of the curve. 



The ordinates of the curve above the line M represent the 

 losses due to eddy currents alone, and the ordinates of the 

 straight line represent the power spent in hysteresis losses. 



EXPERIMENT XXVII. SEPARATION OF LOSSES IN A 

 TRANSFORMER., 



DIAGRAM OF CONNECTIONS. 

 (Same as for Experiment XXV., page 141.) 



Instructions. Connect the transformer to a source of 

 alternating current in series with a low-reading ammeter. 



