[dmparrott]

Hi guys,

I was hoping someone could give me some help with a wiring/grounding question.

First of all, I am a newbie so please bear with me. I am wiring up a control box for my first CNC router. I've got a 70 vdc - 20 amp power supply from Keling Tech ( #7220), a Campbell B.O.B. and three 203 Geckos along with the various other components i.e. fuses, relays, fan, etc. I plan on running some 497 in. oz. steppers with this set-up.

On the secondary of the PS, there are two sides ( two pairs of capacitors ). There are three terminals on each side, both with labels of "+", "-" and "C". My question is this: The "+" side should go to the input to the Geckos but what about the other two? Is the center "C" connection (I'm assuming meaning "common") a ground and should that be connected to the chassis ground? What about the "-" side? I always thought that negative was the "ground" side. One last question: In order to get the full 70 volts@20 amp capacity, do I need to wire both sides of the secondary in series/parallel or can I just run off of one side? Thanks for your help.

Dennis

[Al_The_Man]

You may be need to post a pic of what you have as Three terminals sounds odd.
For my systems, I ground everthing back to a common ground point. This is a good engineering reference, see grounding.
http://www.a-m-c.com/content/support/FAQ.html
Al.

[dmparrott]

Al,

Thanks for your help. I looked over the schematic and it kinda, sorta answers my question.

This is the link to the Keling PS that I'm using. http://www.kelinginc.net/KL7220.pdf. Possibly the terminal marked "C" is a center tap? The reason I say this is that when I power up the supply, I get 68 Vdc between the "+" and "-" terminals and 34Vdc between the "+" and the "C" terminals. This applies to both sides of the secondary. In this case, would I connect both sides in parallel to keep the voltage at 68vdc and double my current output or just run off of one side? If I do connect them in parallel, do I need a separate ground wire? Thanks.