A line voltage monitor/alarm a very good idea. Am surprised Dave's KPA500 power transformer core was not humming away at 60hz over excitation before he got it off line?Being retired from a large electric utility substation department, I know LTC (load tap changer) controls can sometimes fail. For those on a very rural line it could be an overheadline regulator gone to max steps boost (HV) or buck for low voltage. Usually these are single phase large auto-transformers with a plus or minus 10% in 16 steps each side of neutral position. 73 Mike AC5P
On Monday, September 4, 2017 12:33 PM, Mel Farrer via Elecraft <elecraft@mailman.qth.net> wrote: Funny you posted this. I monitor BOTH sides of the 110/220 VAC service and have alarms set to trigger either line >125 or >250 VAC. Being in the country THINGS happen. Always expect the unusual. Mel, K6KBE From: David Robertson <kd1na...@gmail.com> To: Elecraft <elecraft@mailman.qth.net> Sent: Monday, September 4, 2017 9:39 AM Subject: [Elecraft] Items you think you can depend on Everyone, Over time we can grow complacent on many service items such as electrical power, water and other services over time. Well that can be concerning as many hidden changes can result in damage to your home and equipment. Late late night I came in to my den and was closing down my ham station when I notice my fault light on my KPA500 linear was on. I powered it down and retired for the evening. This morning I powered up the linear (KPA500) and at once I got a fault light and had a high voltage alert. I powered down the linear and checked my input line voltage. It was 137 volts RMS! To be sure it wasn't my imagination I rechecked the voltage with a different meter with the same result. In checking the 220 volt outlet I measured 274 volts! My linear is set up for 220 volts operation and it was getting over 90 volts HV. I alerted the neighbors and cut the main breaker to the house. I then called the power company's service number and reported the problem. A short time later they called me back and reported that a regulator in the local sub station had "Stuck" and was reset. In rechecking my line voltage it was 118 volts on the low side and 236 volts on the high side. In the 12 years we have been at this qth we found that our town's locally run power company has been very reliable but this experience showed me that it is not a bad idea to check your line voltage every once in a while. 73 -- Dave Robertson KD1NA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to farrerfo...@yahoo.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to a...@sbcglobal.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com