Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
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Don Whatever is used as a circuit protection device, it is there to protect the hidden wiring from the distribution panel where the fuse or circuit breaker is located to the outlet, it is not used to protect the load.? It is good practice to add a fuse to a consumer radio when it is in for repair but few appliances have such protection.?? I believe that our vacuum cleaner has a thermal circuit breaker.? Not sure about the microwave oven or the fridge but they are both close to the 15 amp rating of outlets protected by 15 amp circuit breakers.? I live in Hot Springs, Arkansas.? The local electric code does not allow for anything smaller then 12 AWG wire so the smallest circuit breaker allowed is 20 amps. Regards. Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Thursday, July 11, 2024 at 05:55:50 PM CDT, don Root <drootofallevil@...> wrote:
First,? sorry for?? the email that flew of my bit machine,? I went on line and deleted it. Ed I guess we are OT a fair bit, but you and Jim raised? stuff related to ¡°turn-on¡± situations. As I recall in NA motors were typically required to draw less than 600% [locked-rotor] current? depending somewhat on the HP. It was known that these sacrificed efficiency for nicer starting as seen by lights on the same line, which is especially a problem for farmers and other rural people. ?European motor standards? allow higher startup / locked rotor current ?and their fusing standards expect this but put one of them on our wiring and you might have a problem. The standards NA vs Europe [perhaps old now] are/were not compatible.? Your problem is just like the farmers, as well as mine, since I am right at the end of the local line, so real dips come from the neighbors¡¯ A/C unit too. ? RE: Same sort of goes for radios of old. ?I blame the NEC++ ?for allowing a? 0.35 amp radio to be *protected* by the 15 amp house fuse ?¡¡ don ? From: [email protected] [mailto:[email protected]] On Behalf Of edward schumacher
Sent: Thursday, July 11, 2024 5:47 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Your last paragraph brings to mind all the issues we encountered at the railroad when we began to try to improve on the original systems in our older equipment. We were doing in house overhauls and switching to more modern technology in the various subsystems. New improved AC units using high efficiency motors was one of the bigger changes. It opened a whole can of worms. ? We had no ready replacement for the main motor--alternator that provided all the working voltages for all the auxiliary equipment in the cars so nothing was changed in that system. Imagine the surprise when the AC switching on caused the MA system to shut down. The much higher, though shorter, starting current of the AC caused enough voltage sag to the MA system to trip a field failure fault in the protective circuits and shut down the MA. ? Various soft start units were installed as well as having to change a number of system circuit breakers with proper curves to work with the upgraded devices. Took quite a while for our starry eyed "new efficiency" engineers to finally get everything playing nice again. The old technology worked because it was capable of handling what it was fed. ? Same sort of goes for radios of old. They were not really that sensitive to some things unless a design got too close to a limit somewhere and then smoke. My Signal One CX-7 was known for burning the ON-Off switch along with the Surgistor on it. Don't think anyone ever got into a close analysis of what the culprit was. It did have an early application of the hypersil transformer at over 1kv for the output tube. ? Bottom line is applying new tech to old tech may not be as easy as one would like. ? 73 ... Ed, WA9GQK -- don??? va3drl |
Jim Whartenby