Hi Doug:
> Isn't this a variation of using the traces as a fusing element > instead of using a real fuse? Not necessarily. In Peter's situation, the test was that of the integrity of the insulation between the TNV circuit and the other circuits. So, if the "fused" trace did not bridge the insulation, then there should be no consideration that the trace was being used as a fuse. It is simply a failure, and a particular kind of failure -- open-circuit. Many, many fault-condition (abnormal) tests end up with an open circuit. We don't treat all component open-circuits as fuses. So, why should we treat an open trace as a fuse? It is unlikely that fusing of a trace will bridge a safety insulation. On the other hand, fusing of a transformer winding wire may be associated with enough heat to damage the solid safety insulation within the transformer! On the other hand, if the fusing of the trace should prevent an overheating situation (fire?), then the trace probably should be evaluated for its fusing action. So, one needs to understand the nature of the test in order to evaluate the results of the test to determine whether the opening of a trace is a fusing action as opposed to simply the end of a fault-condition test. Best wishes for the New Year, Rich ------------------------------------------------------------- Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 619 655 3329 16399 West Bernardo Drive FAX : +1 619 655 4979 San Diego, California 92127 e-mail: [email protected] ------------------------------------------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
