| 摘要 |
930,195. Automatic circuit-breakers. GENERAL ELECTRIC CO. Feb. 12, 1962 [Feb. 14, 1961], No. 5245/62. Class 38 (5). A motor-driven cam-operated circuit-breaker has a second cam coupled to the main contact driving cam and a dash-pot coacting with the second cam for dissipating the kinetic energy of the motor drive after de-energization so as to stop the main cam. As shown, the contacts 12, 16 are closed by one complete revolution of the cam 40 which moves the toggle linkage 23, 24 over centre into engagement with a stop 44. Two further cams 107, 62 are mounted on the shaft 54 of the cam 40 and the shaft 54 is driven by a motor 50. The cam 107 controls contacts 56 which take over from initiating contacts 85 and de-energize the motor after the cam point 88 disengages the roller 42 of the toggle joint 25. Further movement due to kinetic energy is opposed by the dash-pot 60 as a roller 70 is driven downward by the cam 62. The dash-pot has a piston 64 with a metering opening 65 and non-return valve 66, 67 and stop 69 formed in the dash-pot cylinder 63 prevent the return force of spring 68 moving the piston upward to rotate the cams in the reverse direction. On initial energization of the motor 50 the piston will be driven downward until the cam point 80 passes the roller 70 but during this movement there is no to the linkage 23, 24, 20 and contacts since the roller 42 engages a part 90 of the cam 40 having a uniform radius. A trip-free mechanism comprises a latch 32 normally retaining a roller 31 on a pivot-pin 28 for the toggle link 24. The latch 32 is controlled by a solenoid 34 fed by a current transformer 35. The lever 29 on which the pin 28 is mounted has a return spring 49. |
