GB247593A - Improvements relating to electric switches - Google Patents

Abstract

247,593. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of Aalborg, C.). Feb. 12, 1925, [Convention date]. Automatic circuit-breakers for direct-current traction &c. circuits have a floating lever 1 carrying the bridging contact-member 2 which is pivoted at its lower end 15 to the lower end of a bell-crank lever 18 which moves about a fixed pivot 26 and has the end of its second arm 19 pivotally attached at 32 to the core 31 of a closing electromagnet 4. The contact-member 2 is maintained closed by the attraction of an armature 44 to a. manitaining electromagnet 42 the armature being attached to a U-shaped pivoted lever 51 pivoted at 52, a link 53 connecting this lever to the contact lever 2. A straight conductor 45 passes through the air gap of electromagnet 42 and is connected in parallel with a reactor 46 in the load circuit so that on a sudden current surge the magnetic effect of the current passing through conductor 45 shifts the flex of the electromagnet 42 from the upper to the lower pair of pole faces and the attraction of the armature is then overcome by a spring 6 acting on the contact lever which moves it rapidly to the off-position in which its rear portion 34 is held against a fixed stop 33 which may be provided with a shock-absorbing spring 35. Tore-close, the closing electromagnet 4 is energized, rotating the lever 18 about its pivot 26 against the action of the spring 7. During this movement the pivot pin 15 between levers 1 and 18 moves in a clockwise direction, the lever 1 moving about the fixed stop 33 as a fulcrum so that the link 53 moves to the left bringing the armature 44 into engagement with the poles of electromagnet 42. On de-energizing the electromagnet 4 by opening its control switch 65 the spring 7 returns the lever 18 so that its rear portion nearly engages the adjustable stop 29, the contact lever during this movement pivoting about the point 13 at which it joins the link 53 and so bringing the member 2 in engagement with the fixed contacts, the lower of which may be attached thereto by a flexible lead 41. An arc chute 36 and blow-out magnet 37 are provided and a resistance 66 may be arranged across the circuit-breaker contacts.