nr.SICX Cll.lR.ICTF.RlSTlCS or EI.F.CTRO magnets 2i\ 



Kij;. IS shows the (losign features for the supervisory and rinRinR 

 frf<|ueiH-\- relays. In this figure the winding; has been omitted so 

 as to show dearly the unusually small core. This construction is 

 especially efficient in circuits where the relay receives at times a 



rA-!>«i^ iDs'-UCT SCRIW 



C-<Ei"-^<.C- b'K'NO scr^" 



Fig. 18 



very small amount of energ\- for operation and must also release 

 reliably against a leak current immediately after operation by a com- 

 paratively large amount of energy. The small core saturates mag- 

 netically on a relatively small current or energ>' so that excessive 

 energy" does not store up additional magnetism which would retard 

 or prevent the release of the relay. 



Referring further to Fig. 18 the micrometer screws "A" and "B" 

 are used to adjust the back and front contacts respectively, and to 

 fix both the unoperated and operated positions of the armature. 

 The screw "C" is used to control an armature restoring spring which 

 is in the form of a flat spring riveted to the armature. These 

 relays are generally provided with individual cov ers which are efifective 

 in preventing cross talk of telephone voice frequencies when used 

 as supervisory relays in telephone switchboards. 



