Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
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Don I am not posting here to argue, I am trying to understand what the posted data means and how it adds to the understanding of the HT-37 power transformer failure.??So far, there was almost no information given on how the power transformer was tested, what type of loads were placed on the windings during tests, and so on.?? Without this information, I don't see how any of the o'scope images are of any use.? When I have asked, what I thought were legitimate questions, I get replies full of rebuttals and wild guesses on what might be causing what was presented.? This has led to several off topic replies from this end.? Sorry about that chief. I have learned a lot while debunking these guesses and I now realize that I have made some wrong assumptions on how a transformer actually works.? Apparently I got lost wading through the weeds. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 08:41:34 PM CDT, don Root <drootofallevil@...> wrote:
Jim they are both right, but for the sake of argument the in-phase is right, and it is right for a long time, but when the switch closes there is a good chance that the combination of left over flux, and switch closing angle will try to drive the flux past the normal peak and when things go to one extreme the core saturates extremely. In which case the inrush is so big that it swamps the load current, but likely when it is real high the transformer is no longer a ¡°transformer¡±. I¡¯m not sure it I the same image, but on one you could see the small load current partially ?going to the right, but at the left you see the load current rise then the ?inrush swamps the waveform., so it was not the worst case. If the transformer was really left saturated, the current would shoot up with no delay with the voltage. I recorded a 30X inrush on a Honeywell visicorder. That core was being driven very hard. Too many volts per turn. That was a early class H potted transformer, maybe 25 or 50 kVA. Fusing as a real problem for it. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 8:13 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? OK, back to the beginning. Some of Halden's scope images show the transformer's primary current in phase with the voltage across the primary, a few show a 90 degree phase difference with voltage leading current by 90 degrees.? Which is right? Jim ? -- don??? va3drl |
Jim Whartenby