Well here is the schematic:



I'm not sure what type bridge rectifier to use, there are so many to choose from. I want a reliable one.

 

What's the turns ratio on the transformer? If it's 20 to 1 it's a 12 volt supply, and you're going to get a max of about 20amps on the secondary. So pick a full bridge rectifier that can handle 20 amps, if you want better reliability try a 40amp rectifier as it'll put less stress on the diodes, you pay more though. Not sure what you mean by types of bridge rectifier to use. They're pretty simple and standard, four diodes.

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Its made to be a 35v supply. The only thing it tells me about the transformer aside from the schematic is that it should be a rating of 150VA (3A) minimum.

The place I got this from also states to use a 35A rectifier.

Which is fine, however when I am looking to actually buy one, I need to specify three phase or single phase. I assume this is going to be single phase since its not being used on a huge power line. However, I was not aware there was a distinction. Why couldn't a single phase rectifier work on a 3 phase signal?


Anywho, what I was mainly looking for was a brand reccomendation.

Oh, and would a 200V rating on it be overkill?

 

Then why not follow Elliott Sound Products advise?.

Three phase uses more diodes (six instead of four), but I've never heard of being asked that if you ask for a bridge rectifier.

No, that's fine - and probably the value you should be looking at.

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Right here it askes for different phase types in a bridge rectifier:
http://www.digikey.com/scripts/DkSea...S&Cat=32375488


Now that I got that down however, I just have to find a transformer that isnt too expensive.
What do you think about this one:
http://cgi.ebay.com/Toroidal-Transfo...QQcmdZViewItem

 

Well it might help if you had your location filled in! - as it is we've no idea where you might be, but here's a suitable source if you're in the UK!.
http://cpc.farnell.com/jsp/endecaSea...sp?SKU=FF01566

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

You asume it's going to be single phase? You're building this circuit, if you don't know what phase power you're using something is drastically wrong here! You can't pick component values for a bridge rectifier if you don't know what the transformer output is going to be..

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Perhaps I mislead you with the use of the word "assume". I was using it in a sarcastic manner...jokingly. Replace "assume" with "know".


And I am from the US.


And I want to get this one off ebay
http://cgi.ebay.com/Toroidal-Transfo...QQcmdZViewItem

Because it is the cheapest I can find, and it appears to be everything I need. 160VA, A pair of 25V outputs, and 3.2amps.


I do have a question about the wiring though. I can't seem to find a good color code guide. Anyone know where I could find one? I only see 5 connections made in the schematic to the transformer, yet the one in the picture that I was going to buy has 6 leads.

 

You're not going to find a standard colour code for transformers really, you can tell what lead leads to what section of what coil with an ohm meter.

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If it has 6 wires it sounds like 2 wires are for the primary, and it has two coils (in what configuration i don't know, and is winding dependant) If it's two halves of the same coil you can just tie the two ends closest to each other together and you end up with a 5 wire transformer like in the schematic. Which sounds like it's going to give you 50 volts out with a ground refrence at 25 volts relative the the rest of the power system. I'm not sure what will happen if you hook that kind of transformer up in paralell, as the voltage/power is going to be out of phase?

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hmm, it says it has 2X25v outputs with 0v ground. Grrr...why is it so hard to find a transformer?!

 

It's not, it's a VERY common and standard transformer - it could have three secondary wires (and be 25-0-25) but they are more commonly two seperate 25V windings and you simply connect them in series, and in phase - it's more versatile that way.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Thats what I was thinking but Sceadwian said that would give me a 25v ground.

Thanks a ton for the help so far Nigel! I plan on ordering all the parts soon. I'll be sure to take pictures once I get started.

 

i have never seen a schematic like that before. what is the second rectfier from the center tap going to earth ground?

 

If you notice my previous post?, I said it came from Elliott Sound Products, the article there explains why it's done like that!. It's from a guitar amplifier, and it's to prevent earth loops.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk