By code you only have the Earth ground the parts that are used to enclose the high voltage electronics. So handles and carrages are not grounded. The motor case would be if the motor used high voltage. But in the case of a small CNC mill or lathe like what I have the motors are running off 36 volts so a ground is not needed. But a bigger machine might have 270V inside.
On Mon, Jul 16, 2018 at 12:04 PM andy pugh <bodge...@gmail.com> wrote: > On 16 July 2018 at 19:24, Chris Albertson <albertson.ch...@gmail.com> > wrote: > > > Those grounds are best thought of as part of the mechanical enclosure. > > Those safety grounds do nothing at all until one day there is a fire and > > some insulation melts > > One of my machines was a lot like a lathe, with a cast iron bed. > Bolted to that bed was an electric motor, a torque meter, an angular > encoder, something I have forgotten and then the pump under test. > > There were earth wires run to each item bolted to the bed. > > If that is necessary then a CNC lathe needs an earth wire to the > carriage, the toolpost, the top-slide, each handle.. > > They had read that a fixing bolt can not be used to conduct protective > ground. (Which might well be true) and saw that as an instruction to > earth every separate metal part. (which is the logical conclusion from > the prior statement) > > -- > 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 > -- 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
