Transformer Specs Requested
500VA or 625VA
Outside diameter not exceeding 140mm
Dual 120V Primaries 50/60 Hz
Dual Secondaries with 20Vac and 25Vac taps on each secondary both rated at the maximum VA rating. Kills three birds with one stone.
Specified secondary voltage maintained at max rated power
5% Regulation or better
Magnetic shield
Electrostatic shield
350mm fly leads on primarys
250mm fly leads on secondarys
500VA or 625VA
Outside diameter not exceeding 140mm
Dual 120V Primaries 50/60 Hz
Dual Secondaries with 20Vac and 25Vac taps on each secondary both rated at the maximum VA rating. Kills three birds with one stone.
Specified secondary voltage maintained at max rated power
5% Regulation or better
Magnetic shield
Electrostatic shield
350mm fly leads on primarys
250mm fly leads on secondarys
Just for my own curiosity, what sort of specs/voltages/core size etc are you looking for?
<eye's a pile of transfo's he has in the shed thoughtfully>
Edit: doh, was looking at the wrong page.
Edit Edit: - I've some Harbuch transformers here I got for a song. Single primaries, 30V dual secondaries, either 500va or 625va (I can't remember off hand). I appreciate that may not be ideal, but... well I'm happy to donate one to a good cause if you want to pay the postage, so you can't beat the price!
<eye's a pile of transfo's he has in the shed thoughtfully>
Edit: doh, was looking at the wrong page.
Edit Edit: - I've some Harbuch transformers here I got for a song. Single primaries, 30V dual secondaries, either 500va or 625va (I can't remember off hand). I appreciate that may not be ideal, but... well I'm happy to donate one to a good cause if you want to pay the postage, so you can't beat the price!
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No worries - just an offer. 
I'm following this thread because I've always had a hankering to utilize them for something, and maybe this could be the way I can put them to work.
It'd be a whole extra chassis/heatsinking/etc, but I only honestly need one power supply at a time, so why not grossly overengineer one? Anyway, I am indeed watching with interest to see where this goes.
I'm following this thread because I've always had a hankering to utilize them for something, and maybe this could be the way I can put them to work.
It'd be a whole extra chassis/heatsinking/etc, but I only honestly need one power supply at a time, so why not grossly overengineer one? Anyway, I am indeed watching with interest to see where this goes.
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It'd be a whole extra chassis/heatsinking/etc, but I only honestly need one power supply at a time, so why not grossly overengineer one? Anyway, I am indeed watching with interest to see where this goes.
Yes these are also my thoughts.
Hence the reason for dual taps. Pretty much covers anything I would ever like to build.
I haven't made a decision yet but I want to give some cudos to Toroid. Toroid Corporation, US manufacturer of Toroidal Magnetic Components
This company has been the best in terms of professional service.
Richard Sumner and Plitron probably second. The problem with plitron though is that they quoted a ridiculously expensive price for a custom made transformer.
This company has been the best in terms of professional service.
Richard Sumner and Plitron probably second. The problem with plitron though is that they quoted a ridiculously expensive price for a custom made transformer.
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I presume from your description that you're looking for a 650VA units with dual 25V ac secondaries, each tapped at 20 V ac (reduced VA to about 520) and still be under 140 mm diameter
I'd suggest either Toriody.pl (from Poland - excellent), or the Tortech's also very good -
not sure if they'll make the 140mm dia with the taps - the Avels are now out of China
My 500va, dual 25v sec (no taps, unfortunately) is 130 dia and a very good trannie indeed - not the cheapest by a big margin, but ....
I'd suggest either Toriody.pl (from Poland - excellent), or the Tortech's also very good -
not sure if they'll make the 140mm dia with the taps - the Avels are now out of China
My 500va, dual 25v sec (no taps, unfortunately) is 130 dia and a very good trannie indeed - not the cheapest by a big margin, but ....
I have visited Toroid corporation's factory in Salisbury Maryland and can tell you they have a great staff there. Ming Xu will sit down with you and design a custom toroid of just about any size. They have no problem building a single unit and they will build it quickly. I ordered an out of stock standard toroid for a F5Tv2 on Tuesday and they wound it Wednesday, should be shipped today.
Well Ido not see any in thr va range smaller than 142 from Antek.
The AS 4218 is smaller than 140mm, but I want at least 2 x 500VA with magnetic shield and electrostatic screen.