1. ## Please tell me if I´m totally off PSU

This is what I´m hoping will work like a breeze.

I´ve got 3 Toroidal transformers 42volt 350VA, About 6 amperes?, Supplying one Geckodrive each at about 55-60 volts after capacitors and rectifiers.

Am I right so far?

How big should the capacitors be?, got 3 from a migwelder at 3farad each.

Motors are rated 4,5 amperes and 4,05 volts

2. Originally Posted by gotis
How big should the condensators be?, got 3 from a migwelder at 3farad each.
BTW in English it is Capacitors, Condensers has not been used for around 60yrs, (except in the automotive trade).
Are you sure about the 3 Farads? They would be probabaly be as big as the Migwelder itself.
Al.

3. Originally Posted by Al_The_Man
BTW in English it is Capacitors, Condensers has not been used for around 60yrs, (except in the automotive trade).
Are you sure about the 3 Farads? They would be probabaly be as big as the Migwelder itself.
Al.
Ok on the lingo, thanks

Hard to read the text on the capacitors but they are somewhat bigger than a coke can. ) any Idea how big I need?

How about Supplying the Drives separately? OK or down the drain?

4. gotis: you want to fuse the drives seperately if your using a shared supply, as you have enough current to run all 3 motors normally, which is probably enough to cook one if it stalls and the others arent on.

As for the capacitors you need, well the higher the capacitance the more smooth the final dc output is. There is a formula for calculating the minimum capacitance needed, ive posted it before but cant remember off the top of my head, just search the forums, this question gets asked a lot.

two things you need to know about your caps, rated capacitance, and rated voltage, as you want a voltage rating a reasonable margin above your Vdc. 1F is a very big number in capacitance terms, and you rarely see that high a figure, most are measured in uF.

5. Here is a post from the guru Mariss that I have referred to that helped me:

http://www.cnczone.com/forums/showpo...24&postcount=5 (Excessive capacitance)

Steve