On Fri, Jul 13, 2018 at 9:25 AM Roland Jollivet <roland.jolli...@gmail.com> wrote:
> > That's pretty much standard these days. > > I don't understand the desire to connect two lines together because they > 'seem' to be of the same magnitude. 0VDC is Not equal to Gnd > Many systems will have multiple 5V power lines, heavy, light, designated. > Do you want to link all those up too? > Generally you want you power supply and logic nd safety grounds to be separate. But at ONE and one one point would you connect them. What's happening here is that some "grounds" are carrying current exactly equal to the power supply current and unless yu are using "super conductor" cable cool with liqi=ud helium there *will* be a non-zero voltage on the "ground" cable. That is the problem with interconnected grounds, all those return currents and by Ohm's law "return voltages". But if yu do connect safety and return grounds at ONE point current can't flow. But this is hard to do. Really hard if there are multiple 3-prong power plugs. > > > On 13 July 2018 at 18:05, andy pugh <bodge...@gmail.com> wrote: > > > On 13 July 2018 at 16:52, Dave Cole <linuxcncro...@gmail.com> wrote: > > > > > That's pretty much standard these days. > > > > > > I'm not making this stuff up. That's how its done. > > > > I think that there is still some confusion out there. I used to work > > for a company making specialist test equipment (brake dynos, motor / > > pump testers, that sort of thing). > > Our electricians were convinced that everything needed an yellow/green > > earth connection. Every panel for the control cabinet, the doors, the > > individual devices bolted to the machine bed. We would spend ages > > making things look nice and painting them, and then they would come > > back festooned with stripy wires and with a hole drilled in every > > separate metal part for the earth stud. > > > > -- > > atp > > "A motorcycle is a bicycle with a pandemonium attachment and is > > designed for the especial use of mechanical geniuses, daredevils and > > lunatics." > > — George Fitch, Atlanta Constitution Newspaper, 1916 > > > > ------------------------------------------------------------ > > ------------------ > > Check out the vibrant tech community on one of the world's most > > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
