| 摘要 |
<p>834,963. Control of D.C. motors; electricallyreleased switches. TELEMECANIQUE ELECTRIQUE. April 1, 1958 [April 5, 1957], No. 10500/58. Classes 38 (3) and 38 (5). Electric motors M1, M2 are operated in a forward direction by moving controller handle A to close contacts IAV1, IAV2, and open contacts IAB1, IAR2, a reverse contactor CAR being kept closed at this time by means of a permanent magnet so that current flows through contact IAV1, coil CAV, resistor R, coil CAR and contact IAV2. This current flowing through the coil CAR is sufficient to de-magnetize the contactor whereby contacts CAR2 are closed and a heavy current passes through the coil CAV to energize the forward contactor. Contacts CAV1, CAV2 are then opened so that a reduced current maintains the energization of the forward contactor. Closure of contacts CAV3 operates contactor CL for closing line contacts L, and, since contacts AV1, AV2 are closed, the motors start in the forward direction. A rectifier D prevents discharge current from other contactor-coils from opposing the holding current of the contactor CAV, whereby the latter is not released when the other contactors are operated. The reverse operation is similar to that described. If, during forward running operation, a break occurs in the winding of the contactor CAV, the contactor nevertheless remains operated owing to the provision of a permanent magnet. An attempt to start in reverse under these conditions is unsuccessful because contactor CAR cannot close, and, since contacts IAR2, CAV3 are closed, the contactor CL cannot engage. The contactors CAV, CAR have shafts TAV, TAR, to which are fixed the various contacts of the contaetors, these shafts being mounted in bearings G screwed to bars H. These bars are connected by crosspieces I which form elements of the magnetic circuits of the contactors. The magnetic cores are fixed to the cross-pieces and comprise two parts N1, N2, which have low and high retentivity, respectively. The shafts TAV, TAR have a connecting-rod M to prevent simultaneous closure of the contactors.</p> |
