advice needed

[trubleshtr]

Need some advice on what size bridge rectifier to use on my power supply.
also does anyone re-call the formula for approximating the output after rectified? there was a magic # to multiply by but I can't re-call it.
I tried to attach a quick drawing of my design, hope it turns out, please feel free to comment on the design.

[trubleshtr]

Oh ya the drawing is in auto cad 2000

[Al_The_Man]

If you post it in DXF more people can read it. My Acad 14 does not. The number after rectified and smoothed (capacitor added) is to multiply the ACV x 1.414 minus around 1.3v for each rectifiers drop.
Al

[sendkeys]

unless that is a mistype running 50 volt caps like that will end up burning up or going pop :P your voltage will be 80 or so. if you mean "ac 60 out" not dc 60 out. think that was just a typeO :P

[trubleshtr]

Thanks, that 1.414 I always forget.
Sendkeys you are right that is a type-o, 60vac out of the toroidal then rectified (60 * 1.414 = 85 vdc) yup, that will deffinetly blow those 50vdc caps. I guess I can unwind a few rolls on the xtransformer?
Any Idea how much to remove? I need to run my servos at 50 vdc. I was told the 60vdc is unload voltage and once loaded will drop into the 50 vac range? does that sound right? (then 50 vac * 1.414 = 70 vdc) still too high for the 50 vdc caps?
probably.....

[trubleshtr]

Here is the simple drawing again, thanks for the tip Al.

[trubleshtr]

Ops, just realized It did not up-load, I get invalid extension when trying to upload as a .DXF file?

[Al_The_Man]

It is best to find out the turns/volt before you take turns off, put a temporary winding on off any kind of insulated wire, a piece of stranded 24g can be used if you do not have magnet wire, wind about 10 turns and power up the txfr and measure the voltage on the temp winding to find out the turns/volt. On a toroid, you will probally find it is around 2 or 3 turns/volt.
Al

[Al_The_Man]

Originally Posted by trubleshtr Ops, just realized It did not up-load, I get invalid extension when trying to upload as a .DXF file?

Upload shows DXF as a valid extension, was it the size?
Al

[trubleshtr]

I get "invalid file type"?

[sendkeys]

Originally Posted by trubleshtr Thanks, that 1.414 I always forget. Sendkeys you are right that is a type-o, 60vac out of the toroidal then rectified (60 * 1.414 = 85 vdc) yup, that will deffinetly blow those 50vdc caps. I guess I can unwind a few rolls on the xtransformer? Any Idea how much to remove? I need to run my servos at 50 vdc. I was told the 60vdc is unload voltage and once loaded will drop into the 50 vac range? does that sound right? (then 50 vac * 1.414 = 70 vdc) still too high for the 50 vdc caps? probably.....

should be around 69 or so (after the -1.3 for brige)
for what im told most you can push a cap 10% ,so that is alot more. you can run them side by side with a resistor jumping over to make a 100 volt cap. but then it will only be 5,000 uf that sounds to small to me.

http://www.digikey.com/scripts/DkSea...352407&Site=US is a 15,000 uf for 14 bucks. sounds alot cheaper then maybe making a cap go pop and killing your controllers.

[trubleshtr]

Ok, I have figured out what I did wrong. Here are the very rough drawings of my intended plan. the first one with caps. in para;;e;; wont work for my purposes, the second one includes 2 bridge rectifiers which I need help figuring out sizing on, and putting the cap's in series to get 100vdc capability?
please correct me and my drawings if I am wrong.
thanks
and if I don't reply for a few days merry xmas to all.....