208 



ELECTRICAL MACHINERY 



such a circuit is low. In fact it often occurs in the laboratory 

 that a wattmeter is burned out when the indicating finger 

 shows only a fraction of the full scale deflection; the low 





FIG. 125. A Portable Wattmeter. Weston Electrical Instrument Co. 



reading is due to the low power factor of the circuit and is 

 low in spite of the fact that the current through the meter 

 is dangerously high and may be burning the windings. 



Wattmeter Ammeter 



factor are to 

 be measured 



FIG. 126. Connection of Meters for Measurement of Power and 

 Power Factor. 



Connection of Meters for Determining Power and Power 

 Factor. Fig. 126 shows the connection of an ammeter, 

 voltmeter, and wattmeter to a circuit in which it is desired 

 to know the power consumption and power factor. When 

 it is desired to obtain the highest possible accuracy of 



