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THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1957 



Fig. 6 — J-7 solenoid valve. 



the armature of the valve. The push rod, G, attached to the armature, 

 is connected to an S shaped spring, H, which tends to keep the movable 

 assembly centered, or the valve closed. 



When a current passes through the coil, J, magnetic flux passes 

 through the fixed pole piece, K, through the coil housing, L, then across 

 the small annular air gap, M, to the moving pole piece, F, and across the 

 air gap between the pole faces near the center of the coil. Flux in the latter 

 gap causes a force on the armature which tends to pull it and the valve 





o 



^i 



Fig. 7 — Hydraulic parts of the J-7 valve. 



