I believe the term "bad," as applied to a fuse which has functioned as intended, is a report of its (no pun intended) current condition, rather than its suitability for the purpose. A better word, I think, and still accessible to laymen, is "blown."
>> On the other side fuses and fuse holders were probably the least reliable components we had with defect rates of 4 to 80%. << Reliability rightfully includes surviving shock and vibration; a complete specification for an application would include what stresses a component (not just fuses) must endure before, during and after installation. Many fuses ARE mechanically fragile; it's simple physics that says a low-current fuse will be a fragile thread. Think of them as light bulbs. We do not call a light bulb unreliable if it fails after being dropped on the floor; we call it broken. Perhaps we should specify our fuses to last long enough to be installed? I've heard of a "bad" fuse, in this case, a fuse not adequate to protect the circuit and user. A 30 volt fuse can't be counted on to interrupt a 408 volt circuit. There were frightful physical consequences (which I did not see, thank God) and also legal ones, the echoes of which I did get to hear. But here, the fuse itself was not malfunctioning, either, only badly specified. >> I forbad my testers from using the term "bad" or its military equivalent "NFG" on their failure tags << I ran into this myself, some years ago, as an Army avionics tech. Since we were forbidden to write "INOP," we had to describe what symptoms were observed. Having worked both line and bench I understood why, too. But perhaps "Modulator transistors get hot enough to boil spit" was more than they wanted to know. Cortland This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
