| 摘要 |
375,340. Controlling traction motors. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London, TUPPEN, E. B., 54, Hillmorton Road, and BUTLER, F. E., 74, Eastlands Road, both in Rugby. Feb. 17, 1931, No. 5023. [Class 38 (iii).] Safety arrangements.-Incorrect working of motor control apparatus in a traction system during passage of collector shoes over rail gaps is avoided by arranging relays so as to increase the effective length of the gap. When either shoe 2a, 2b, Fig. 1, leaves the rail, the corresponding relay 6a, 6b drops and immediately opens the circuit of the no-volt coil 9, which causes the opening of the main contactors 5. These do not reclose until both shoes have passed the gap and both relays have returned to their normal raised positions, sufficient timelag being given to the reclosure of the no-volt relay to obviate premature resetting. The novolt coil may be shunted through an impedance by a switch interlocked with the line contactors, for the purpose of accelerating the drop-out action and delaying the reclosure. The relays may be interlocked mechanically as shown in Fig. 3. When either coil is energized, both relays lift up to the point where catches 23 release a plate 26, whereupon the other relay drops its coil is sufficiently energized. |
