GB647557A - D.c. impulse operated selector switch - Google Patents

Abstract

647,557. Electromagnetic switches. GUARDIAN ELECTRIC MANUFACTURING CO. Feb. 28, 1948, No. 6334. Convention date, Aug. 19, 1940. [Class 38(v)] A predetermined number of impulses delivered to an electromagnet 32 causes the reciprocation of the armature 36 and the step-by-step rotation of a ratchet wheel carrying a contact arm 22 till the arm engages a selected contact 16 and so prepares a circuit 17 which after a short time interval is completed for a predetermined time through the automatic release of two timelag D.C. relays 56, 70. Both these relays have copper slugs 56b, 70b giving them a slow release. When impulses from the circuit 100, 101 are delivered to the magnet 32 the reciprocation of its armatures 36, besides rotating the ratchet wheel, actuates contacts 78, 79 causing the intermittent energization of the relay 70 which, owing to the copper slug, attracts and keeps attracted to its armature thereby opening contacts 86, 87 in the main circuit between the lines 1 and 2 and closing contacts 88, 89 which cause the D.C. energization of relay 56 which closes contacts 82, 83 in the main circuit and also allows a check pawl to engage the ratchet wheel and prevent its return. When the series of impulses ceases, contacts 78, 79 permanently open causing the timed release of relay 70 which first closes contacts 86, 87 so completing the selected circuit between lines 1 and 2 and then opens contacts 88, 89 causing the later timed release of relay 56 and the breaking of the selected circuit at 82, 83. The check pawl also disengages the ratchet wheel so that this and contact arm 22 return to starting' position.