GB469611A - Improvements in or relating to electric relay apparatus - Google Patents

Abstract

469,611. Electromagnetic switches and actuation of switches. GRASEBY, R. C. Jan. 24, 1936, No. 2291. [Class 38 (v)] [Also in Group XXXVIII] A relay apparatus comprises a relay-device connected by supply and pilot wires to a mechanically independent master-switch device which, on closure of its contacts to energize the pilot wire, automatically maintains the said wire energized for a predetermined period, the main contacts or other operative members of the relay-device being actuated by a self-starting electric motor excitable initially from or under the control of the pilot wire and subsequently through auxiliary contacts adapted for being closed and held closed for a predetermined period by the action of the motor so that the latter will continue to run until the end of the last-named period irrespective of the condition of the pilot wire. As shown in the Figure, on closure of a control contact 13 such as by a push-button, time switch, &c., a circuit is completed for a motor 12 which may be of the synchronous clock type. The consequent rotation of the motor shaft causes a cam 15 to engage contacts 14 and complete the motor circuit independently of the push-button &c. so that the motor continues to run until the contacts 14 are opened at the end of a predetermined rotation of the shaft i.e. half a revolution in the construction shown. During this rotation, further contacts 17 in a controlled circuit are operated by a second cam 16 and connect a pilot wire 5 to one of the main conductors 3. During this connection a relay arrangement similar in construction and arrangement to the apparatus previously described is brought into operation and controls by a cam 11 and contacts 6 the connection of a lamp 7 across the mains 3, 4. To ensure the completion of operation of secondary relays such as 1 the period of rotation of the motor 12 of the master relay 2 is made long enough to ensure that it does not come to rest before the motors 8 of all secondary relays. In modified arrangements, the operating contact may be automatically latched in position and tripped mechanically after a predetermined rotation of the motor 12 so that the motor operated relay arrangement may be brought into operation by an electromagnetic relay.