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Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Halden, now that everybody has been silent, ¡°would an SSR that turns on at zero voltage and turns off at zero current put the core back to zero every time and prevent current surges at turn-on¡± I
By don Root · #30491 ·
Re: SR-400 REPAIR MANUAL
Thank you, Walt!! You are amazing with a ton of knowledge! Thank you, Mike W5CUL From: [email protected] <[email protected]> On Behalf Of waltcates Sent: Tuesday, July 9, 2024
By Mike · #30490 ·
SR-400 REPAIR MANUAL
Just completed a rewrite of the SR-400 series repair manual. This update fills some holes in the transmitter fault analysis which includes a transmitter troubleshooting flow chart. Go to wd0gof.com
By waltcates · #30489 ·
Re: Halicrafters SX17 transformer
JohnDownload the Stancor transformer catalog from?http://www.tubebooks.org/file_downloads/stancor_1952.pdf Check top of page 12 for a formula to calculate the turns ratio for the interstage
By Jim Whartenby · #30488 ·
Re: Halicrafters SX17 transformer
John, if the existing one has been declared ¡°grabage¡± you might assume that the failure is very near the coil end[s] and see if you can find the break and measure the ohms. And maybe be lucky and
By don Root · #30487 ·
Re: Halicrafters SX17 transformer
A little more detain on this transformer. I found the code A-4931* on its side. I found some Standcor catalogs online with A-47xx numbers, but not A-49xx. * corrected. original post erroneously stated
Re: Halicrafters SX17 transformer
I have not posted for a little while for various reasons but have returned to the SX17 project in the last few days and followed up on the previous suggestions. I am reasonably certain that the mains
By John · #30485 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
As far as I know, the inrush current problem was due to the limitations of vacuum tube rectifiers then in use.? Filter capacitors just do not care about the initial charging current.? At the instant
By Jim Whartenby · #30484 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Halden?I can't answer your question.? I don't know all of the pitfalls of using an SSR in place of a mechanical switch.? I don't know if there are any unintended consequences.? The SSR will turn
By Jim Whartenby · #30483 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
I usually work on tube audio, so we as a group have been installing movs to lessen the shock to transformers and filaments for a while, and filter caps when converted to s/s rectifiers
By Scott Petersen · #30482 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Maybe a spark gap, or a s/s equivalent...would fix it. ________________________________ Sent: Thursday, July 4, 2024 4:41 PM To: [email protected] <[email protected]> Subject:
By Scott Petersen · #30481 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Halden, that is common and in many forms you always see the reference It is easy here if you use email and indent [what I normally do] , I used to be able to do it on line, but my secret does not work
By don Root · #30480 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Halden, very interesting and thoughtful comments getting into the nitty-gritty. Re the turning off part: The switch needs to break any current and open the conduction path enough to withstand the
By don Root · #30479 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Rick , so have you or anyone looked at switch-off transients of the original switches? And also contact bounce on closing for other reasons? Re some SSRs see
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
FYI, in case my posts don't seem to be in logical order, it's because they aren't.? My messages appear on the forum in a sequence different from that in which I submitted them for posting.? Maybe
By HF · #30477 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Hi Jim, Thanks!? So, would an SSR that turns on at zero voltage and turns off at zero current put the core back to zero every time and prevent current surges at turn-on? Halden
By HF · #30476 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Hi Don, Thanks for bringing us back to the original question and for mentioning one of the options I hadn't listed!? Turning the transformer OFF at a particular time relative to the AC voltage cycle
By HF · #30475 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Scott, I worked on three phase power supplies that had some premature transformer failures. The engineers had us install MOVs across the primary windings for all three phases. Never seen another
By David Balma · #30474 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
It appears that some experimentation could? in order. If you have a dual trace scope, you can easily measure the input voltage & current on the transformer primary and observe the phase difference
By Rick W7IMM · #30473 ·
Locked Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
I wonder if a MOV could be somehow used to soften the inrush, if not one perhaps 2 in some kind of toggle arrangement. ________________________________ Sent: Thursday, July 4, 2024 2:56 PM To:
By Scott Petersen · #30472 ·