[Jcadwell]

Any reccomendations for power supply use with HomeCNCs servo motors? I want a supply that will power 4 using Gecko 320s, and be 36 volts or so. What kind of amperage do I need? Thanks.

[HomeCNC]

I am telling everyone to build a 36VDC supply @ 20-25 amps.

[Jcadwell]

Excellent, I'll design one up then. Thanks.

[thuffner3]

May I see the design when you get it drawn? Just Newbie interest.
Thanks

[ljoe1969]

i would like to see that also.

[Jcadwell]

Sure, I'll have to get on it then. I'm looking around at Iron to see what I can come up with that isn't unaffordable. What cost bracket is desirable? Getting it under 150 isn't too hard, getting under 50 requires more creativity.

[Patrick2by4]

could you also list the websites (or vendor ) where you got the parts
-thanks

[owhite]

I recently put together a power supply using this schematic:

http://www.plitron.com/pages/technote.htm

See the "Full Wave Bridge"

I went about the design process using this terrific tutorial:

http://nilno.com/laser_dir/power_supply_design.pdf

which was written by this guy:

http://www.campbelldesigns.com/

Here is a longer discussion of how I designed my power supply:

http://www.nilno.com/laser_dir/archi...1_archive.html

and a thread on cnczone when I had a problem with the toroidal transformer producing too much voltage that was repaired quite elegantly:

http://cnczone.com/showthread.php?s=&threadid=2924

Almost all parts were purchased on ebay, except the toroidal power transformer which I got here: www.plitron.com. For power supplies of the size 36vdc @20 amps, you probably dont need a toroid, you may be able to go with transformers like at these sites:

http://www.angela.com/catalog/transf...nsformers.html
http://www.hosfelt.com/
http://www.mouser.com/

Building is fun but dont forget that if you search on "power supply VDC" at ebay you may get exactly what you need already put into an enclosure with all the right fuses and switches etc. Many other search terms will also work.


Owen

[owhite]

who's in favor of a "things to know when you're making a power supply" FAQ?

[Al_The_Man]

A couple of points on transformers, the toroid type although usually more expensive is more efficient due to the magnetic field contained with in the transformer itself and not radiated out as with an E/I core type. Therefore it is usually smaller and takes up less space. The other advantage is with a toroid it is easier to either modify a winding as in the CNCzone link Owen has shown. or if you require a separate 5v winding for logic etc, you can wind another secondary, which for 5v would be around 15 to 20 turns. Use enamel wire (used to be known as magnet wire). The gauge would depend on the current drawn. You would also have to watch you do not exceed the total V/A rating of the transformer.
Al

[ynneb]

I made this last night because I have always wanted to show visually what happens in a power supply. I could have more details but settled for this. It is debated if electrons flow from positive to negative or the other way around, so please have mercy on me if you dont like my diagram

[Al_The_Man]

I think you got it right, but I don't think electron flow is actually debated anymore, The old tube technology actually demonstrated that electrons flow from negative to positive, but we still tend to use 'conventional flow' (pos to neg) rather than electron flow when we are using a demonstration.
Al

[owhite]

check the diode directions. See:

http://www.plitron.com/images/Diagrams/APP6.gif

owen

[Urgundiz]

And in purity, the current and voltage is not 'still oscillating' before the capacitor, because the diode bridge force only positive values. The term normally used is 'rippling', and the capacitor charges and discharges make this rippling more 'flat'.

greetings

/U

[ynneb]

Owhite, the diodes are correct. If you notice in the link you gave, the DC is been taken from the top and bottom of the rectifier, in mine it is been taken from the sides. All it means it mine is rotated 45 degrees and the dc is taken on the left and right.
It is the same schematic just drawn diferently.

Urgundiz, may be the words are wrong but If you note I didnt use the word "alternating" meaning to change direction. I used the word "osiliating" meaning to waver or go up and down.
Rippling is a better word though. I may change it. I was hoping the pulsing arrows would show osillating an not alternating.

He He.........sorry this is not a strick scientific drawing, but in the long run the circuit still works for any one who wants to use it.

[Al_The_Man]

Ynneb, Yeah, the ripple frequency on your full wave bridge is 2x the supply freq (in N. Am 60x2 = 120 hz ripple)
Incidentally I mentioned tubes earlier, do aussies use the term Tubes or do you use 'Valves' as in the UK? Also what is the normal domestic power voltage and freq? 120ac or 240? 60 or 50hz, just curious.
Al

[ynneb]

We call them valves (the things used in old radios). A tube is more often refered to a tv tube.

As standard domestic power we have 240 volts AC at 50 hertz frequency. Most power points are 10 Amps Max.

Our 3 phase is 415 volts active to active and 240 active to neutral.

[tjstraz]

Jcadwell, how did you make out with building this power supply?

I also have the same servos and am looking to build a ps. Care to share your parts list with the group?