Ground loops

[Ron Boyd]

I’ve been reading some stuff about using 2 power supplies for 1 controller. My question is regarding tying the 2 grounds together to NOT create a ground loop. I’m confused on the ground loop issue.

1.       Is it the grounds on the AC input side tied together or the DC output side? The AC side is already tied together at the main power panel, right?

2.      If it’s on the DC side, do I just use a jumper wire from one V- out on PS #1 to a V- out on the #2 PS?

Any help would be appreciated.

Ron

[plasmadrive]

It is the DC side you are concerned with.  Tie the two commons together close to the supplies and/or close to the driver board and you should be golden. 

Edited May 21, 2014 by plasmadrive

[Ron Boyd]

Thanks. That's sort of what I was thinking, but I wanted to make sure.

[Max-Paul]

Just adding to what Plasma said to help paint a picture. Lots say you have two supplies. One is in the same box as the controller. The other one is out and injecting voltage 50" away from the control box. The negative or ground will have a potential difference due to the resistance of the wire. And that is between the ground and the signal wire. We see this more often on longer wires that carry communication. And its the actual shield of the cable. One way to keep this from happening is to hard ground one end and put a .01 up disk cap. between the shield and earth ground.