I did not know "It's was the way it was always done."
I think you're suggesting that I make a full wave rectifier. I'm not attached to the idea of a bridge rectifier. I just want it to work. If it would yield sufficient voltage and I'm more likely to be successful then that's what I'd want to do.
If I was to make it full wave rectification as opposed to bridge rectified would I be able to use 1.2 kV diodes if I did this? Or would I require 2.4 kV diodes?
I think you're suggesting that I make a full wave rectifier. I'm not attached to the idea of a bridge rectifier. I just want it to work. If it would yield sufficient voltage and I'm more likely to be successful then that's what I'd want to do.
If I was to make it full wave rectification as opposed to bridge rectified would I be able to use 1.2 kV diodes if I did this? Or would I require 2.4 kV diodes?
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Top diagram you have 850V rectified & smoothed = (850x1.4) = 1090V.
Bottom diagram you have 425V rectified giving (425x1.4) = 595V; closer to what you want.
Assuming you have the centre tap not connected in the top diagram and are connecting to the outer wires of the secondary?
Both are full wave rectified but only the top is a bridge.
Bottom diagram you have 425V rectified giving (425x1.4) = 595V; closer to what you want.
Assuming you have the centre tap not connected in the top diagram and are connecting to the outer wires of the secondary?
Both are full wave rectified but only the top is a bridge.
Of cause it is better to use full-wave rectifier but not bridge one if you have center-tap transformer.
The maximum diode voltage can be about 1.2...1.3 kV, so it is unsafe to use 1.2 kV rated diodes. It is much safe to use serial connected ones.
Ready-made PCB on Ebay are usually made for low voltages, and are not good for AC voltages higher then 200-300 V RMS approximately.
The maximum diode voltage can be about 1.2...1.3 kV, so it is unsafe to use 1.2 kV rated diodes. It is much safe to use serial connected ones.
Ready-made PCB on Ebay are usually made for low voltages, and are not good for AC voltages higher then 200-300 V RMS approximately.
I see russc, more than enough voltage for the regulator. And if I connect the diodes in series then I can use the 1.2 kV diodes.
Ok guys, I think I understand what I need to do. I feel confident enough now to order a few diodes and do a point to point full wave rectification with 2 diodes in series (4 in total.)
Thanks for taking the time to help and explain things to me!
Ok guys, I think I understand what I need to do. I feel confident enough now to order a few diodes and do a point to point full wave rectification with 2 diodes in series (4 in total.)
Thanks for taking the time to help and explain things to me!
Series connected diodes don't necessarily share the voltage drop equally. See the article here: Diodes in Series
Maybe this diode would work and be a better choice: https://www.mouser.com/ProductDetai...Y5Fr7%2B/6iiQWaVK6aHfoyAYzqzyc4EfTkMP7qLHsQ==
Maybe this diode would work and be a better choice: https://www.mouser.com/ProductDetai...Y5Fr7%2B/6iiQWaVK6aHfoyAYzqzyc4EfTkMP7qLHsQ==
OP, firstly I am concerned that your experience and awareness of such power supplies may lead to a safety issue. You need to appreciate that there are serious safety issues with this type of power supply, including what is being done on the primary side, and what protection is being included on the secondary side (such as voltage rating of wire and terminals and even the inclusion of over-current protection).
Perhaps if you show a schematic of what you are doing on the primary side as well for starters.
I suggest you confirm the secondary winding taps, even if there is colour coding of wires that match the manufacturers details - that would require winding resistance checking which it doesn't sound like you have done.
I suggest you identify the max current requirement of the amplifier, and the type of regulator being used, as that will confirm what type of diode is ok, and whether you have sized the transformer and regulator ok, and what over-current protection is practical.
It would be safer for you to use a single diode with sufficient PIV, which that FFPF10F150S does have for a 425-0-425V secondary. The use of series connected diodes requires some caveats to avoid using any additional sharing components - sadly that linked article in post #25 does not adequately represent what is happening and what is practically allowable, and just goes straight in to representing that additional sharing parts need to be used.
I suggest you make the effort to check your own design by using the simulation software called PSUD2 - as that would provide a learning curve on parts and what voltages and currents are flowing in your circuit, and why.
Perhaps if you show a schematic of what you are doing on the primary side as well for starters.
I suggest you confirm the secondary winding taps, even if there is colour coding of wires that match the manufacturers details - that would require winding resistance checking which it doesn't sound like you have done.
I suggest you identify the max current requirement of the amplifier, and the type of regulator being used, as that will confirm what type of diode is ok, and whether you have sized the transformer and regulator ok, and what over-current protection is practical.
It would be safer for you to use a single diode with sufficient PIV, which that FFPF10F150S does have for a 425-0-425V secondary. The use of series connected diodes requires some caveats to avoid using any additional sharing components - sadly that linked article in post #25 does not adequately represent what is happening and what is practically allowable, and just goes straight in to representing that additional sharing parts need to be used.
I suggest you make the effort to check your own design by using the simulation software called PSUD2 - as that would provide a learning curve on parts and what voltages and currents are flowing in your circuit, and why.
Now that we know what all of this is connected to, yes the bottom diagram in post #21 is what you need. The top diagram will feed over 1000 volts into your poor regulator if the diodes survive, which will invite the fire gods to dance all over it as well. It may also be damaged from the excess input voltage.
For this application I would use something rated for a bit more that 1KV. I have been working with a 40 watt per channel SE tube amp. I'm using a pair of DSA1-18D diodes for a B+ around 600 volts and haven't blown one yet. They are rated for 1800 volts at 2.3 amps. They are about $3.70 each though. You only need two.
Sometimes people think 500 volts dc rectified means they need about 500V rectifier.
On negative cycles the transformer goes negative 500v which gives 1000 volts across the diode. So you need a diode with reverse voltage of over 1000 volts.
On negative cycles the transformer goes negative 500v which gives 1000 volts across the diode. So you need a diode with reverse voltage of over 1000 volts.
I've used a pair of 1N5408's (3A,1000V) in numerous supplies like that, and never ever had a problem.
Simple.
It doesn't need to be so complicated.
Simple.
It doesn't need to be so complicated.
It is that complicated when he is getting flames !
In 40 years I have never had a power supply die.
In 40 years I have never had a power supply die.
Thanks for the words of warning and concern. Although the voltage was high I didn't feel like I was in any danger. I set it all up then flicked the switch on my dim bulb tester and then either read the readings on the multi-meter or turned off the dim bulb tester if the bulb lit up or I heard that crackling sound or saw the flash. I never work on a live amp or even touch it when I turn it off or on. If anyone sees any problem with my method and has any recommendations or advice, I'm all ears.
All the specs for the regulator, transformer specs and amp requirements I worked out with Tom and feel confident that they're correct. The only thing I did on my own was the rectifier. And it looks like that was the Achilles heel of my project.
Either way I'll be careful and besides it doesn't look like I'll be working with voltages over a grand any longer! lol
All the specs for the regulator, transformer specs and amp requirements I worked out with Tom and feel confident that they're correct. The only thing I did on my own was the rectifier. And it looks like that was the Achilles heel of my project.
Either way I'll be careful and besides it doesn't look like I'll be working with voltages over a grand any longer! lol
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At this sort of voltage people usually use series strings of 1kV diodes with parallel capacitor/resistor strings to force good voltage sharing. This link shows a commercial version to illustrate the idea.
You probably only need 2 or 3 in series to get adequate voltage overhead. I've seen PCBs before with full-bridge rectifiers built up this way for high voltage stuff. Once you're up to these kind of voltages paxolin tag-strips aren't suitable IMO, FR4 or ceramic is a better choice for char-resistance should flashover happen.
Flux should be cleaned off very high voltage circuits, it will support combustion if there's flashover, and can carbonize over time to form a conductive path.
You probably only need 2 or 3 in series to get adequate voltage overhead. I've seen PCBs before with full-bridge rectifiers built up this way for high voltage stuff. Once you're up to these kind of voltages paxolin tag-strips aren't suitable IMO, FR4 or ceramic is a better choice for char-resistance should flashover happen.
Flux should be cleaned off very high voltage circuits, it will support combustion if there's flashover, and can carbonize over time to form a conductive path.
In my work, the high voltage anode of older TV sets usually required a HV rated silicone sealer on the anode connector of the picture tube.
This prevented moisture buildup due to humidity, and prevented flashovers as well.
For some amplifer work, a traditional silicone sealer like GE Silicone is fine.
This prevented moisture buildup due to humidity, and prevented flashovers as well.
For some amplifer work, a traditional silicone sealer like GE Silicone is fine.