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
