Diy Power Supply Choices

[berin]

My big question to you guys is. What kind of power supply should we design or suggest. As the basis for the begginer just starting out for the first time?
The easy choices would be a standerd AT computer power supply, because of the power source involved. 12v 6amps norm..
and a 5v soruce good for controling circuits. The other choices would be for a higher power supply design using multi transformers (one per motor). Yet an other choices for a straight liner power supply is to use one LARGE transformer to drive each stepper driver in parallel. 12-30v 4-8amps often.
The multi transformers are good in the fact that there is no shared drain, when running multi motors in parallel. Not to mention size, you can get plenty of 16-30v 1-2amp transformers all to fit in the same area as you would a standerd PC AT power supply.
What are you guys thoughts on this matter? DONT forget price is always an issue! cheapest is always best, and I dont mean quality.

[High Seas]

berin - maybe 2 tracks - one for the DIYer that wants to build from scratch - and then another something simple - like "off the shelf" or as you suggest using a pc supply.

I'm pretty much in the basic electronics category [even got to take EE over in summer school - shoulda paid better attention and not cut class - ahhhh the 60s were something else!!!!]
Guess it makes a difference which motor it would be mated to, and controller (board) -- right? Amybe we should get a survey (spreadsheet - or whatever) of the "typical" motors and their power requirement to help bound the solution set? Any volunteers - sorry I have not gotten much response on my survey attempt - else I post those results for us to start with.

Good start up - thanks! Jim

[jmcroft]

Another problem I've run into, is that the controller board I'm using uses a common power supply for the X,Y, and Z axis. So pay close attention to the board you buy.

Since my x,y and z motors are all using the same power supply, then I'm forced to use a power supply that can handle alot of amps. If you have 5 motors pulling 2.2 amps each then that adds up quick. High amp power supplies are quite spendy, especially if you want to drive your motor at high voltage to speed it up.

So make sure you consider both items when buying your controller and power supply.

[pacosoide]

You can use a switching power supply for your controller. The At type is the most common and inexpensive.
You can get those from obsolete computers for about 5 dollars. They don't get any cheaper than that. Trust me. They have the problem that they can not provide for a lot of juice (amps) on demand. So if your controller summons two motors simultaneously the supply may not be able to provide the energy necessary. So basically your motors will sort of slow down initially and then catch up to speed. That is why you see the supplies designed for this particular purpose (good supplies) have large capacitors in the output section. They store the extra energy for the sudden demands of 2 axis moving simultaneously. The AT power supplies have usually a 1000 uf in the output section. Hardly enough to supply energy for one single axis motion. Again your budget should dictate what you get.
JOse

[intrusion]

I agree that a switching power supply be used as pacoside suggests. You should read the free white paper from Gecko Drives www.geckodrives.com then click on Support. You can download the entire Stepper Motor White paper or the individual sections. This paper describes pretty well how to size a power supply correctly for the job and how best to wire your stepper drives to it. It will also tell you why a switching power supply is best to use. I use it as a reference every time I have to purchase a new power supply for any given motor/drive combination.

Intrusion

[Dylwad]

Taken from the geckodrive white papers~

The drive works best with unregulated power supplies though regulated linear and switching
power supplies may also be used. What matters is the power supply must have a large output
capacitor and an unregulated supply intrinsically has one.

another route is to go to www.partsexpress.com and look for toroid transformers, get a bridge rectifier and capacitor and your set, the white papers give instructions and formulas for building a power supply.



http://www.geckodrives.com/ycom/docu...r_supplies.pdf

Dylan

[Bubba]

And my favorite DIY is to rewind an old micro wave transformer, add a bridge rectifier and humongous cap and call it done!

Works for me

[pminmo]

http://pminmo.com/simpleps.htm About 32VDC at 10A.

Phil

[rippersoft]

You may want to try looking at the posts in the General Electronics forum. Lots of what-if about power supply construction. I finished a 4 transformer 38VDC 16Amp PS from surplus parts and put it all in a spare PC case.

[ViperTX]

Are you sure an AT supply has 12 VDC @ 6amps? Well firstly you need to know what your requirements are, before you design a supply(s).....did I miss the requirements?

[H500]

12v won't give you much performance. You need at least 20-30v unless you don't mind the low speeds.

[joecnc2006]

wire them in series, I get 32.8v 8a out of three pc power suplies, wired in series with floating groung.

Joe