GB113502A - - Google Patents

Abstract

113,502. Pickett, F. N., and West & Co., A. March 2, 1917. Electro-magnetic switches. -In a lock-out switch having a shunt closing-coil 4 and a series holding-out coil 2, while the end 6a of the pivoted armature 6 is under the influence of the holding- cut coil the other end of the armature is completely outside the influence of the closing winding and vice versa. The switch is shown in the normal position; when the coils are energized, an auxiliary armature 7 pivoted to the frame of the holding and closing magnet 3 is attracted thereto and puts in tension a spring 7<a> located between the two armatures. When the current in the holding-out winding falls, the spring becomes effective to move the end 6a of the main armature out of the influence of the coil 2 and to bring the other end into the influence of the coil 4 so that the switch is finally wiped home magnetically without opposition from the holding-on windings. An auxiliary pole-piece may be provided to co-operate with the auxiliary armature. The pivoted member 6 may be mainly non-magnetic and be provided with a small armature to serve as the closing means. In the construction shown, the auxiliary armature 7 when attracted completes a shunt magnetic circuit round the shunt coil and thereby limits the current therein.