BALANCED POLAR MERCURY CONTACT RELAY 



1401 



measured after applying a given ampere turn soak in each of two polari- 

 ties. 



SPEED OF OPERATION 



Fig. 7 shows typical operate times of the relay for one balanced adjust- 

 ment and one biased adjustment. The ordinates correspond to time to 

 effect closure at the opposite contact after input is applied to the coil. 

 The abscissae are shown both in terms of power in the full relay winding 

 and the corresponding number of ampere turns. Two circuit conditions 

 are indicated, one in which the voltage was applied directly to the full 

 winding and the other in which the voltage was appUed through a re- 

 sistance equal to the coil resistance. 



The winding used in this case is one which is specially designed for 

 speed rather than sensitivity, being shorter in length, with the working 

 gap near the middle. Its time constant (inductance-resistance ratio) is 

 about 0.0006 second. 



Fig. 8 shows "release" time measurements, where the relay, with 

 various biased adjustments, was operated by opening the circuit. The 

 curve is shown plotted against the "operate" setting of the relay. In this 

 form it is relatively independent of the differential ampere turn adjust- 

 ment. 



The time required to open the contact from which the armature moves 

 is typically about 0.0002 second longer than the closure time, as the 



2.25 



1.50 



1.25 

 1.00 

 0.75 

 0.50 

 0.25 



^^m 



^X""*^ 



O X 



40 



80 120 160 200 240 



N.I. SOAK VALUES PLUS AND MINUS 



280 



320 



Fig. 6 — Change in NI. To operate versus plus and minus NI soak. 



