On Sunday 29 December 2019 09:19:40 Henk du preez wrote: > That schematic is basically the same as what I do. > > You can add a 230v transformer instead of using the neutral and one > phase. Most machines I have worked on have those, but I have done it > the way you are showing. > > The other question is the grounding of the screens of the analog, > encoder, and step/dir signals. These should be connected to earth at > one end and the other left unconnected. Not sure if it really makes a > difference which end.... > The shields/screens are connected to that common bolt, and left unconnected at the far end. Ditto for the drive cables to the motors, should be screened and the screens grounded at that common bolt.
If you can src some of the "star-quad" microphone cable which is 4 conductors spiraled with a braided screen/shield, in a gauge heavy enough to drive motors, common for mic's is 26 gauge and is too light, its great stuff, ultra flexible and follows the motor around for many years. But most versions of it are too small a gauge and will heat a wee bit if you have sensitive fingers. I've used miles of it both for studio mic cable at the tv station and for motors. Clark Wire & Cable in Chicago is my main src. 22 gauge will handle most sub 4 amp steppers. If you call them, tell Suzan we still need an 18 gauge version of that stuff for bigger motors. She gets it from some Japanese maker, and it might be available under a different name in NZ. > Henk > > > On Sun, 29 Dec 2019, 14:37 , <emc-users-requ...@lists.sourceforge.net> > > wrote: > > Send Emc-users mailing list submissions to > > emc-users@lists.sourceforge.net > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.sourceforge.net/lists/listinfo/emc-users > > or, via email, send a message with subject or body 'help' to > > emc-users-requ...@lists.sourceforge.net > > > > You can reach the person managing the list at > > emc-users-ow...@lists.sourceforge.net > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of Emc-users digest..." > > > > > > Today's Topics: > > > > 1. Re: looking for advice on best wiring practices and grounding > > on cnc mills (andrew beck) > > > > > > -------------------------------------------------------------------- > >-- > > > > Message: 1 > > Date: Sun, 29 Dec 2019 23:37:36 +1300 > > From: andrew beck <andrewbeck0...@gmail.com> > > To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> > > Subject: Re: [Emc-users] looking for advice on best wiring practices > > and grounding on cnc mills > > Message-ID: > > <CALQw8iM=2HNVzhS7FVDbe0y= > > c+-_a8ce_sasvjzasqbzcot...@mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > Hey everyone > > > > So just getting to the bottom of these emails and thanks so much for > > all the replies. > > > > There is much food for thought. > > > > If you missed it up in the emails here is the current plan for > > wiring the control panel. > > > > yuhai servo drive manual > > < > > https://drive.google.com/file/d/17inZoRboGQP3lqn0KHd343NlmDQ1CxzS/vi > >ew?usp=sharing > > > > Linuxcnc mill control panel drawing > > < > > https://drive.google.com/file/d/1rJYzUGXLrSKuDARQ878wc5RlkjgPqSCr/vi > >ew?usp=sharing > > > > > > All the three phase stuff is pretty standard I think. The main > > problem I have is that I am not sure how the grounding should work. > > Eg do I tie the 24 volt powersupplies to ground on the input or > > output etc and any safety stuff I need to make sure I do. > > > > The only opti isolation I have is in the mesa 7i76 card. > > > > So any thoughts feel free to let me know. I am planning on powering > > this up tomorrow. > > > > Regards > > > > Andrew > > > > On Fri, Dec 27, 2019 at 8:03 AM Chris Albertson > > <albertson.ch...@gmail.com > > > > wrote: > > > A ground loop is then a single device is connected to ground more > > > than once. A good example is a motor driver. It might in a > > > "power" input called "+" and "-" with the minus side grounded to > > > the AC mains ground or a chassis frame ground. The in > > > addition there is a logic level control signal that is "signal" > > > and "ground" wires. This is a classic gound loop. > > > > > > How to break it? Use optical isolation on the signal. This > > > places an air-gap in the control signal. > > > > > > Most of the time the system is not so simple as the above but the > > > concept is the same, multiple ground connections are not good. > > > Why? Because in theory current can flow if you have a loop but can > > > never flow if there is not a closed loop. Then Ohm's law applies > > > -- if there is current flow there is voltage drop. If the > > > voltage drops across a gound then you have tow "grounds" that are > > > not the same voltage. This can be really serious if the motors > > > are large. > > > > > > There are a number of conventions that work. but they all do the > > > same thing, they reduce the number of ground connects to one per > > > "part" of the system. > > > > > > All the rules try to do the same thing, connect nuetral to ground > > > ONLY at the building service entrance, use opto's on all signal > > > lines. It is all the same idea > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------ > > > > > > > > ------------------------------ > > > > Subject: Digest Footer > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > ------------------------------ > > > > End of Emc-users Digest, Vol 164, Issue 89 > > ****************************************** > > _______________________________________________ > 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. 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