On Thursday 12 July 2018 17:31:17 andy pugh wrote: > On 12 July 2018 at 20:12, John Dammeyer <jo...@autoartisans.com> wrote: > > Is it standard practice to connect the DC Servo and DC > > Instrumentation Bus to the machine frame ground which is connected > > to power line earth? Or is it more normal practice to keep the DC > > isolated from the 'earth' ground. > > I think it might be a good idea to keep the high voltage DC bus > separated from Signal Ground. I don't know this for a fact and I am > only mentioning it because the other replies seem to be glossing over > that part of the question.
So I did Andy, but the connection there cannot be opened if you are using one of Jon's pwm-servo amps to drive the spindle, which I am. In that driver, ground, the negative end of a 126 volt multi-amp (around 20) supply, and the common of the pwm signal that controls it are one and the same terminal on that driver. I too would like to see some isolation there, but it does in fact work well if the rest of the grounding is solid. Twice, as thats essentially the same circuit in The Little Monster 7x12. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ 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
