I think I can do this, but thought I should ask... All Antek power torroids come with two 115v primary windings. Id like to use one of those primaries as a 1:1 secondary, as well as using all the other secondaries as normal secondaries. This shouldn't be a problem right? After all they are all wound around the same core.
Random example but all Anteks have the same two primaries:
https://www.antekinc.com/content/AS-3435.pdf
The specs say to wire the primaries in series or parallel depending on your line voltage, but in the USA at least cannot the extra primary be a secondary?
Random example but all Anteks have the same two primaries:
https://www.antekinc.com/content/AS-3435.pdf
The specs say to wire the primaries in series or parallel depending on your line voltage, but in the USA at least cannot the extra primary be a secondary?
You probably can't. Isolation problems easily.....unless each one runs on half of the toroid and there is isolation between the 2 halves. Up to you if take a risk and burn it. In case they are isolated, each one on half of the toroid, you would get uneven coupling across all windings.
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In theory it will work, but remember to derate the VA rating by 50% at least. It will still be isolated (otherwise it wouldn't work as dual primary - they would short each other) but you might be relying on the enamel on the magnet wire instead of a proper insulation wrap layer.
It shouldn't be pulling much over 150ma. I need 340v B+ which I was going to get with a voltage Doubler on that 115v primary winding. I also need a whole bunch of low and mid voltages by using the other secondaries. If this works then I wont need two transformers:
you can do this is capacity is not a concern for you...
btw, make sure you do not drop toroid's, i had an antek toroid with open primaries, i suspect that during manufacture the toroid was dropped and landed at its sharp edge...tearing down the secondary coils revealed the broken wires of the primary winding....
you have a big traffo there, 300va...so drawing about 40 watts is peanuts...
btw, make sure you do not drop toroid's, i had an antek toroid with open primaries, i suspect that during manufacture the toroid was dropped and landed at its sharp edge...tearing down the secondary coils revealed the broken wires of the primary winding....
you have a big traffo there, 300va...so drawing about 40 watts is peanuts...
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In my experience, 340V from a doubler is wishful thinking if there's a load. 320V is easy though 🙂
I built an amp that uses a doubler from a 572VA supply. Idle current is ~500mA. Open circuit is 350V, loaded is ~315V or so using 470uF as the doubler caps, less if using 220uF. The R in the CRC filter is 5R1 which accounts for ~2.5V
I built an amp that uses a doubler from a 572VA supply. Idle current is ~500mA. Open circuit is 350V, loaded is ~315V or so using 470uF as the doubler caps, less if using 220uF. The R in the CRC filter is 5R1 which accounts for ~2.5V
mmmm this idea was just a thought around what stock Transformer. I may abandon it I wasn't even gonna use that 300va it was just an example of an Antek. In afterthought I'd want something stiffer than the Doubler. Thx.
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what is the dc resistance of that 120 vac winding? i use voltage doublers all the time simply because i use tv scanning tubes where G2 voltages are 150 volts typical....
my experience, is as long as the dc resistance of the winding is low enough, then regulation is not an issue....
everything has a context, and you can make calculations too....
perhaps an online psu calculator will surface soon if not here already...
there is a lot to learn from Patrick Turner tube psu blog....powersupplies
my experience, is as long as the dc resistance of the winding is low enough, then regulation is not an issue....
everything has a context, and you can make calculations too....
perhaps an online psu calculator will surface soon if not here already...
there is a lot to learn from Patrick Turner tube psu blog....powersupplies
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Also, keep in mind your isolation requirements. As member 45 pointed out, there is more attention and winding-space (as a precious resource) devoted to isolating the primary(s) and secondary(s), since the primaries are expected to be connected to the same voltages / ground references.
I like the idea, though -- clever, I say. 😉
Cheers
I like the idea, though -- clever, I say. 😉
Cheers
i built an isolation traffo 750 va, 230 to 230 vac....
my winding method was bifilar.....that was almost 15 years ago, still working good till today.....so i would not share the same concern if the toroid was well made...
my winding method was bifilar.....that was almost 15 years ago, still working good till today.....so i would not share the same concern if the toroid was well made...
Thanks, for this project its probably not the best fit because its for the power tubes. But I can see having an extra 120v winding available for other situations where you maybe want to put the voltage tubes on this winding and dedicate the regular secondary entirely to the power tubes rather than doing a big voltage dropper. Good to know.
The doubler works fine for power tubes. All of my designs use a double/quad config to get 320V (power tubes) and 640V (VA/PI/Driver) from an isolation transformer, and most of the time I light up the tubes with SMPS.
I run a quad of 6P45S with 5% regulation with a load that starts at ~0.5A and peaks 3A
Just oversize the coil, and use large caps in the delon. I usually use 470uF doubler caps, a 470uF cap across them, a 5R1 resistor, and 2000uF-4000uF. I use HER308 or FR607 for the diodes in the doubler, and HER108 or HER208 for the quad.
I run a quad of 6P45S with 5% regulation with a load that starts at ~0.5A and peaks 3A
Just oversize the coil, and use large caps in the delon. I usually use 470uF doubler caps, a 470uF cap across them, a 5R1 resistor, and 2000uF-4000uF. I use HER308 or FR607 for the diodes in the doubler, and HER108 or HER208 for the quad.
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