Specialized in reliability at Bell Labs. In switching I used to send people out to new switching offices to blow 100 amp fuses at random or with a good idea .... We analyzed the results in detail to verify grounding of equipment and duplicate power operation. Switching systems were powered via commercial AC, backed up by diesel generators, backed up by batteries. We had procedures well documented as to what equipment to power down first if we got to batteries and needed to preserve minimum service as long as possible. Issues always cropped up in real life. Once had a diesel fail to kick on because a relay failed - impossible to test in operation without big risk of all the crp that happens during the commercial AC glitch. Power doesn't go away fast enough and fault tolerant equipment is challenged with figuring out what happen during the few 100 ms ringing. During a hurricane we once ran cables from a truck on the street with a diesel generator into the building as the diesel fuel on th

(Written on 2016年08月12日)(Permalink)