GB389576A - Improvements in or relating to electro-magnetic switches - Google Patents

Abstract

389,576. Control of motors; electromagnetic switches. GRANGIER, E. L., 22, Rue Ste. Marie, and NIOGRET, F., 48, Rue du Dauphine, both in Lyons, France. Dec. 8, 1931, No. 34068. Convention date, Dec. 8, 1930. [Classes 38 (iii) and 38 (v).] An electromagnetically-operated, push-button controlled switch comprises U-shaped movable contacts 3 mounted on a shaft 1 carried by a frame 7, which is normally held by springs between extreme positions to which it is actuated by electromagnets 12, and in which the contacts 3 engage fixed contacts 18, the cores 8 of the electromagnets 12 moving on non- magnetic guides 9. A latch 22 rests on a pin 24 when the contacts 3 are in the centre position, but falls behind the pin when the contacts are in an operative position, the latch being raised by an electromagnet 28, and closing contacts 30. The switch may function as a reversing-switch for a motor, or, as shown in Fig. 5, it may control a motor to stop it by " plugging " for a certain time. Upon closure of a button ma, the switch moves to the left, in which position it is held by the latch 22 which, at contacts 30, opens the circuit of the operative electromagnet 12. Closure of a button f energizes the coil 34 of a relay 34, 35, 36, in series with the coil 28, so that the relay closes, and the latch 22 is lifted. The relay in closing energizes another of its coils, i.e. 35 in series with the right-hand coil 12, so that the relay remains closed, and the switch moves to its right-hand position to reverse the connections to a motor. The latch 22 is released when the switch moves, and is effective to hold the switch,in its reverse position, the relay 34, 35, 36 remaining closed by the energization of its coil 36 in series with an expanding wire 43. After a certain time the wire 43 allows contacts 40, 41 to open, and contacts 40, 47 to close, thereby energizing the electromagnet 28, to raise the latch 22 and allow the switch to return to its centre position. In a modified arrangement, Fig. 6, (not shown) two relays 34, 35, 36 are provided, electrically interlocked and selectively energized by contacts on the switch, so that " plugging " for a certain time is possible with the motor running in either direction. The Specification as open to inspection under Sect. 91 comprises also arrangements for reversing and " plugging " a motor in which the switch is operated by electromagnets in one direction only, additional means being provided in one arrangement for preventing a stop-button becoming effective until a predetermined time after the motor has started. This subject-matter does not appear in the Specification as accepted.