Another newbie Power Supply Question

[Bimmerkc1]

OK so i've been lurking around the old forum for a couple of months and i don't know about the rest of you but yet again the internet has lead me down a long dark road. You know how you search for something and find another and all of a sudden you have another project that you just have to take on, well yea that's how i ended up with a MAME arcade machine but that's another story. I'll start by saying i have had lots of joy reading the posts in the DIY CNC router threads, so much that i've already built the jrgo machine. I'm a computer geek by trade but i've enjoyed working with wood for a good many years now so the CNC router project seemed like something fun. Like i said before I already have the machine built and for years now i have been collecting misc stuff from old computer systems i've trashed or old printers old tape drives etc. So my plan was to use some power supplys that i took from a old IBM enterprise tape library. I've got 3 and i'm sure they are worth more than gold if you ever had to buy one but i think they will work out. I've tested the outputs and i can get either 5v, 12v, or 24v depending on which output i select. This is where i have questions, see computers i understand and wood i understand, electricity i'm scared of. I've read the articles about linking 2 or more ATX power supplys together and they make sense. I'm probably going to use the Hobbycnc board and 200oz steppers for my little monster so i believe the requirements state that 36v is optimal. If i take the supplys i have and run 2 together i can get 24x2=48v so how would i go about stepping this down to 36v? Like i said before i'm scared of electricity, one too many shocks as a kid or something. I've pretty much scoured through the threads and some of the stuff makes sense but other parts are going over my head. If anyone wants to answer a question that has probably been asked before then thanks. Oh and thanks to all of you guys who share to keep us weekend warriors bogged down in yet another project.

Here are a couple shot of the supplys i'm wanting to use.

Thanks,

Scott

[Oldmanandhistoy]

Hi and welcome to the zone,

I don’t really have the answer you are looking for but for the guys who do a question.

Will you have enough current from them PSU’s?

I am sure the pro’s will be with you shortly; they do get tired of same questions which is understandable but they always come good.

Best of luck with the electronics side of you build, not my favourite part of any project but has to be done.

Regards,

John

[thkoutsidthebox]

Hi, I built the HobbyCNC kit and my power supply for it, I also have the 200oz/in steppers. Is that supply putting out AC or DC? Im assuming DC, but if not then select the 24VAC, and after it is rectified it will go to approx 33.6VDC. This is what mine is at.

However, I believe that a plain old 24VDC is fine to run the 200oz/in steppers. You dont absolutely have to go up to 33V. The main concern is that you need an approx 10Amps power supply there as the motors are 3A each. What current can your supply...supply? !.. ?

[thkoutsidthebox]

Here is a quote from Dave Rigotti at HobbyCNC, from another thread.

Originally Posted by hobbycnc We recommend a 24VAC 10A transformer be used in all cases, 3 or 4 axis. We find the 10A cheaper than an 8A here in the States. This allows upgrading to a 4th axis in the future. 13A tranny is NOT required to operate 4 3A steppers. Keep it simple: 24VAC at 10A, 25A or more at 200V or more rectifier, and a filter cap rated at least 27,000uF at 50VDC.

I just double checked and HCNC recommends 12VDC to 42VDC max for the Pro Driver Board kit, with 24VDC min. Strange that its 12 to 42 and 12 is not the min?...anyway!...I think 24VDC would be fine, just dont feed it with 48V

You could buy a 48V > 36V transformer to step it own if you really want to I think:
http://www.hammondmfg.com/162.htm