Dear fellow experimenters, hello. Yesterday, in the zone near my lab, the weather forecast was of a big storm. I was here doing some work when the sun got covered by clouds and started a strong wind. The neon lights went away for a fraction of a second, not enough for the PC to reset, then, something like ten seconds later, the lights went out, I heared a multiple clicking sound from the electric switch box, then the UPS alarm. I thought it was a blackout, but no, the UPS was in "overload alarm", there was smell of something burned and all chain of three automatic switches powering it tripped.
It turned out that the power supply of my server, protected by the "line interactive" UPS burned out. I opened it, and the chain of resistors and diodes giving the startup power to the control IC UC3843 arched and the IC itself exploded (more details on the circuit later on request, I still didn't reverse engineer it). To this point, nothing exceptional: an overvoltage came from the line and, even if nothing else of the many devices in the lab (fortunately) had been affected, this power supply died. I didn't saw any lightning however and no thunder. The strange thing came this morning, when a customer, having the office 19Km far from my lab in a zone populated enough to have between us some small towns and industrial areas, called because his server was off. Guess? Exactly the same power supply, exactly the same components arched, and the control IC exploded in the same way. Also in their office, no other equipment was affected, everything was running and the UPS didn't went into overload alarm (or maybe it did and recovered by itself, I don't know in effect). Surely we are on the same grid, even if the transformers are obviously different, but despite I have other customers in the zone (none with the same power supply model), I didn't get any other call (while usually I do, when a lightning strike), and, no one reported to me to have had problems with other equipment. Now I just had the idea to check the logs of the servers to see if they powered off at the same time. They did not, the one of my customer powered off 17 hours earlier, when the storm was still far away (it's unlikely the sudden power off erased 17 hours of logs). Could be just a coincidence? Best regards, Andrea Baldoni _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
