I use small tester. I measure supply 120 v ac. Meter works. Axis was moving by them self. Touch box with real ground and breaker turn off. Between box and real ground tester read 30 v ac
On Mar 24, 2018 2:39 PM, "Peter Blodow" <p.blo...@dreki.de> wrote: > Aram, an aluminum box will not shield magnetic noise, you would need heavy > iron walls for that. Aluminum - as any electrically conductive material - > will only help keeping electrostatic noise out, but for this purpose, it > must be connected to a good ground (earth). Telling from your description, > the box is connected to some potential other than ground, and/or the mains > leads carry some other voltage than just zero and 115 VAC. Check the > voltage supply carefully, you may even be in danger of an electric stroke! > What kind of voltage meter did you use to measure those 30 V AC? Try to > repeat this measurement with a load, like a light bulb,connected parallel > to the meter! There may be just some stray voltage if the meter is > sensitive enough, meaning that it may have a very high impedance to show > harmless stray potentials. In any case, your mains supply is suspicious. > > Peter > > Am 24.03.2018 um 21:28 schrieb a k: > >> Hello >> It is sound strange but that what I have. >> I build box 3 3 3 feet >> And put all motor drive inside of it. >> Why ? >> This box build out of aluminum plate and holds together with bolts. >> When all drive inside I have problem ==axis move by them self. >> When I pull out all motor droves, they all working good. >> I build this box to protect against outside magnetic noise = was logical >> Right ? >> But it is not what real situation . >> >> Something not ok, >> Was I wrong with building aluminum box? >> >> >> >> >> >> >> >> >> >> >> >> >> >> On Mar 23, 2018 5:12 PM, "Gene Heskett" <ghesk...@shentel.net> wrote: >> >> On Friday 23 March 2018 19:24:58 a k wrote: >>> >>> I am in portland . >>>> 30 to 40 v ac I read between water pipe _ which is real ground and >>>> ground on the outlet pin that has cylindrical shape. >>>> Is this normal? >>>> >>>> No! >>> >>> But inspect that pipe, every inch of it all the way to real dirt. There >>> may be a plastic connector, inserted someplace which will break that >>> good ground connection. If so, jumper it from one side to the other with >>> a solidly bolted connection using at least 10 gage solid copper wire. >>> >>> Water, depending on its purity is at best a poor conductor, although it >>> can kill you, and really pure water (distilled or deionized) is an >>> excellent insulator. >>> >>> On Mar 23, 2018 4:03 PM, "Chris Albertson" <albertson.ch...@gmail.com> >>>> >>>> wrote: >>>> >>>>> Aram, >>>>> >>>>> Where to you live? In North America, UK, ....? >>>>> >>>>> Building wiring conventions are different in different places. but >>>>> in general your system, taken as a whole needs to be connected to >>>>> exactly ONE ground reference. No more no less. The best way to >>>>> place a bolt some place and define that is "The Ground" >>>>> >>>> And all static grounds are to be stacked on this single bolt. >>> >>> If you have 30+ volts AC on a ground pin on an outlet you have a >>>>> problem that needs to be looked at by a good electrician. It >>>>> should never be that high. Some cases are thinks like corosion and >>>>> loose connections. One cause I that think of is that in some older >>>>> buildings they were allowed to use metal conduit as the ground >>>>> connection. Works OK at first but metal conduit rusts ofter time. >>>>> Now day's we are required to pull a group cable >>>>> >>>> with its own static ground in this cable. >>> >>> On Fri, Mar 23, 2018 at 2:04 PM, a k <pccncmach...@gmail.com> wrote: >>>>> >>>>>> hi >>>>>> i reassemble my lcnc mill, and i found that axis move by them >>>>>> self. i think it is something to do with static electricity. >>>>>> i found ground - and when grounded lcnc body of machine - breaker >>>>>> turn >>>>>> >>>>> off. >>>>> >>>>> i measure with dc voltage between machine and ground 2. vdc and >>>>>> when i measure ac voltage between lcnc machine and ground it was >>>>>> 35 v AC. >>>>>> >>>>>> i know that when use real ground like a water pipe and ground in >>>>>> outlet there always will be current they always be 30 v ac. >>>>>> can it cause problem? >>>>>> >>>>> Yes, and while I'm commenting on a plastic connector, its entirely >>> possible that a teflon taped water pipe joint could be an insulator. >>> >>> thanks >>>>>> aram >>>>>> ------------------------------------------------------------ >>>>>> ------------------ >>>>>> 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 >>>>> >>>> ---------------------------------------------------------------------- >>>> -------- 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 >>>> >>> >>> >>> -- >>> 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 >>> >>> ------------------------------------------------------------ >> ------------------ >> 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 > ------------------------------------------------------------------------------ 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
