512 



ELECTRICAL EQUIPMENT 



indicated by the figures 1.5, 2, 3, 5, etc., in the " Times current 

 tap setting" column. These figures can be translated into 

 amperes by multiplying them by the current tap setting which 

 is to be used. Time settings are made by a lever which changes 

 the length of travel of the disc, the time scale being at the bottom 

 of the index plate. Therefore, with the time lever set over a 

 definite graduation mark, the values given in the correspond- 

 ingly marked column are the approximate time delays, in seconds, 

 which will be obtained at the current values opposite in the 



i s s 4 , o 7 8 o io 20 30 40 50 



Current, in Multiples of Current Tap Setting 



FIG. 317. Induction Type Time Limit Relay Characteristics. 



" times current tap setting " columns. In general, the time 

 delay values should be chosen at a current value approximating 

 the short-circuit current of the line, and the proper setting of 

 the time lever for a given time delay may be determined by 

 referring to the table on the time current index plate. First 

 determine which factor in the " times current tap setting " 

 column represents the current at which this time delay is 

 desired. The position of the time lever can then be found by 

 an inspection of the row of time delay values opposite this 

 factor. 



