| 摘要 |
472,277. Testing for and locating faults. STANDARD TELEPHONES & CABLES, Ltd., and LATIMER, K. E. March 20, 1936, No. 8384. [Class 37] Faults on electrically conducting lines are located by sectionalizing the network and indicating at a test position the load on the separate sections, the test circuits being formed by the network only and the sectionalizing being under complete control at the test position. In a radio rediffusion system, the relays Ra, Rb, of which Ra is slightly sluggish in action, are energized by a continuouscurrent source B, the relay Rb being first energized through contacts of Ra and then through its own contacts. On interrupting the supply Rb is de-energized while Ra holds on. Further energization and de-energization brings in successive sections at rb1 and rb2, and the line is extended, a load indicator at the main amplifier A indicating an overload or faulty section which can then be left disconnected until repair is effected. The sections of main feeders are first tested and then any associated transformer-connected branch feeders ; which, if found faulty, are left disconnected when the reconnecting impulses are transmitted. Alternating-current test methods are employed. |
