Excellent references on what actually works, and stays shipped is available from any of the cnc machine tool manufacturers maintenance manuals. My reference that I used to solve my 8 year long search for intermittent noise problem is from Morbidelli, their U-15 machine (A woodworking oriented panel processor). The Italian and Spanish manufacturers are a great source since all of their machines have to be designed to work with electrical systems all over the world.
----- Original Message ----- From: emc-users-requ...@lists.sourceforge.net To: emc-users@lists.sourceforge.net Sent: Friday, January 1, 2016 11:14:43 AM Subject: Emc-users Digest, Vol 117, Issue 7 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: Smart-Serial cabling (Peter C. Wallace) 2. Re: Rewiring the BP (Bertho Stultiens) 3. Re: Rewiring the BP (Jon Elson) 4. Re: Rewiring the BP (andy pugh) 5. Re: Rewiring the BP (Kirk Wallace) 6. Re: Rewiring the BP (John Dammeyer) 7. Re: Rewiring the BP (John Dammeyer) ---------------------------------------------------------------------- Message: 1 Date: Fri, 1 Jan 2016 09:24:26 -0800 (PST) From: "Peter C. Wallace" <p...@mesanet.com> Subject: Re: [Emc-users] Smart-Serial cabling To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Message-ID: <pine.neb.4.64.1601010903100.7...@freeby.mesanet.com> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed On Fri, 1 Jan 2016, andy pugh wrote: > Date: Fri, 1 Jan 2016 16:59:12 +0000 > From: andy pugh <bodge...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Smart-Serial cabling > > On 1 January 2016 at 16:16, Peter C. Wallace <p...@mesanet.com> wrote: >> SSerial is differential RS-422 at 2.5 MBits/sec and requires ~100 Ohm >> differential cable cable impedance. This usually means twisted pairs >> are required for TX and RX (the 5V/GND power connections are not critical) > > The pairs are twisted inside the individual foil screen with drain > wire then there are 4 other small (0.14mm2) wires and two bigger > (0.5mm2) wires all inside an overall braided screen. > > I suppose the thing to do is to try it and see. I have determined that > the pairs fit nicely in an RJ45 connector, but I can't decide what to > do about the 2x 5V and 2x 0V positions in the connector. Are the 0V > and 5V contacts commoned at the PCB ends, such that leaving two > positions unpopulated in the RJ45 is OK? I only need enough 5V power > to run the 7i73 logic. Yes, they are commoned at the sserial remote and FPGA side RS-422 interface > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > ------------------------------------------------------------------------------ > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------ Message: 2 Date: Fri, 1 Jan 2016 18:29:16 +0100 From: Bertho Stultiens <ber...@vagrearg.org> Subject: Re: [Emc-users] Rewiring the BP To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Message-ID: <5686b76c.4030...@vagrearg.org> Content-Type: text/plain; charset=windows-1252 On 01/01/2016 05:47 PM, Dave Cole wrote: > That's done all of the time. In fact it is part of the NEC (National > Electric Code) that is followed (for the most part) in the US. > Pretty much every house in the US is wired like that. (I'm not making > this stuff up. :-) ) I agree with the connection at power entry in the house. That is quite a different story. That is actually the same here in EU (most countries). I think that we should separate two things: - house installation - machine wiring House installation is pretty much standardized with a lot of rules and reasons. Specifically to ensure referencing and protection. Machine wiring is different in that you can have scenarios where references are moved, especially in a 2-phase system where you are not using the neutral, which is the scenario we have here. > Now, if you don't want to do that inside the panel for some reason > (which I might have missed), that may be a different story. > I'm just saying that is standard practice in the US and on the European > machines I have worked on as well. The reason for /not/ connecting the ground on a secondary winding is to prevent a capacitively coupled ground path. Especially if you cannot guarantee a 100% balanced primary-to-secondary side wrt. ground (*). What happens is that there will be a current in the ground connection which causes an imbalanced current on the primary side (remember: primary is 2-phase circuit without neutral reference). This is a differential current discrepancy on the primary side. If you have an RCD (which you should), then it can or will trip due to the current imbalance. (*) and from the example measurements presented by JT, we can be assured that there is an imbalance, as seen from the phase shift causing a difference in voltage measured wrt. ground on the secondary. > There are a lot of good reasons to tie one leg the transformer to ground > besides to establish the safety ground and neutral as is common on the US. > Intermittent faults to ground, with an ungrounded system, can cause the > secondary of the transformer to fly way above absolute ground causing > connected devices, or the transformer to suffer from insulation > breakdowns. That's the extreme, but it can happen. Actually, the secondary should normally be floating. Most transformer setups are to ensure galvanic separation and that means you may never connect neutral to the secondary side. Connecting ground on a secondary is a different scenario, where you most often see the 0V (DC) potential connected to protective ground. This is often done in the PC's power supply. The 0V (DC) to protective ground connection prevents the scenario to which you refer to. The 0V (DC) to protective ground connection is repeated in many devices, which have both power and signal connections. This gives rise to ground-loops, which are to be prevented at all times and it is the cause of the whole thread. > One of way too many references on the web. > http://ecmweb.com/bonding-amp-grounding/basics-bonding-and-grounding-transformers > It looks like the link is about a 3-phase system, where you would connect the center point in a star-configured secondary to ground. That is a different scenario. -- Greetings Bertho (disclaimers are disclaimed) ------------------------------ Message: 3 Date: Fri, 01 Jan 2016 11:34:37 -0600 From: Jon Elson <el...@pico-systems.com> Subject: Re: [Emc-users] Rewiring the BP To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Message-ID: <5686b8a...@pico-systems.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 01/01/2016 06:02 AM, John Thornton wrote: > Hi Jon, > > So tie say the 48v side to ground to create the neutral? I > attached the drawing of what I have so far on the VFD side. > With power off, use an Ohmmeter to verify the secondary is isolated from the frame. If so, tie either end to ground. If NOT, then further investigation is required. > Happy New year to you and I hope you stayed dry during the > recent monsoon we got. > It was fine here, but lots of highways closed. My mother in law's house had some basement leakage. During the strongest rain, we had a drip where the furnace flue goes through the roof. Jon ------------------------------ Message: 4 Date: Fri, 1 Jan 2016 17:37:17 +0000 From: andy pugh <bodge...@gmail.com> Subject: Re: [Emc-users] Rewiring the BP To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Message-ID: <can1+yzvllkfmw-e8sdwjewmu6nzoowwqob_hdqwbf68ttu7...@mail.gmail.com> Content-Type: text/plain; charset=UTF-8 On 1 January 2016 at 17:29, Bertho Stultiens <ber...@vagrearg.org> wrote: > The reason for /not/ connecting the ground on a secondary winding is to > prevent a capacitively coupled ground path. Another reason is that if you connect either secondary winding end to ground using body parts then nothing bad happens. This is the point of an isolation transformer. If there is an isolation transformer fitted in the machine then grounding one of its terminals makes it pointless. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------ Message: 5 Date: Fri, 01 Jan 2016 10:25:09 -0800 From: Kirk Wallace <kwall...@wallacecompany.com> Subject: Re: [Emc-users] Rewiring the BP To: emc-users@lists.sourceforge.net Message-ID: <5686c485.7060...@wallacecompany.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 01/01/2016 09:29 AM, Bertho Stultiens wrote: ... snip > Machine wiring is different in that you can have scenarios where > references are moved, especially in a 2-phase system where you are not > using the neutral, which is the scenario we have here. ... snip My understanding is, and I could be wrong, that "two-phase" in reference to modern mains circuits does not exist. Circuits with two hot legs, L1 and L2, are single phase and referenced to each other. Two phase used to be two legs that were 90 degrees apart, but is long gone. https://en.wikipedia.org/wiki/Two-phase_electric_power I had fits trying to understand how rotary three-phase converters worked until I purged the notion of the input being two-phase. Two phase does exist for stepper motors. https://en.wikipedia.org/wiki/Stepper_motor#Two-phase_stepper_motors -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------ Message: 6 Date: Fri, 1 Jan 2016 10:45:06 -0800 From: "John Dammeyer" <jo...@autoartisans.com> Subject: Re: [Emc-users] Rewiring the BP To: "'Enhanced Machine Controller \(EMC\)'" <emc-users@lists.sourceforge.net> Message-ID: <09cf01d144c4$89afbe90$9d0f3bb0$@autoartisans.com> Content-Type: text/plain; charset="us-ascii" Here's what I did for my SouthBend Lathe. Not run with CNC but with my Electronic Lead Screw. http://www.autoartisans.com/lathe/SouthBendPower.pdf http://www.autoartisans.com/Lathe/ControlBox.jpg http://www.autoartisans.com/Lathe/ControlBoxInside.jpg The System Relay is wired as a latching relay that stays ON until ESTOP is hit. Both the coolant pump switch and Spindle Start relay must be off before the Relay is energized. An ESTOP disconnects power to the dangerous voltages but leaves the ELS powered. Since I fed this box with 220VAC there is no neutral and I used a transformer to power a split duplex outlet. One side of the 120VAC is bonded to Earth. I haven't had any electrical noise problems. But I have also not yet wired the RS232 port of the ELS to the VFD for speed control. John Dammeyer > -----Original Message----- > From: Dave Cole [mailto:linuxcncro...@gmail.com] > Sent: January-01-16 8:14 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Rewiring the BP > > > Yes, > > Anytime you have a 120 volt source for computer, misc power etc, you > need to declare one side of the 120 vac winding the neutral (white wire) > and tie that terminal to the machine frame. > It similar to what is required at the service entrance of your house. > The neutral is always tied to the ground at the entrance box. > Oftentimes they drive a screw through the neutral buss bar in the > service entrance box into the box sheetmetal and then tie a green or > bare copper ground wire to the same neutral buss bar and run that to a > metal water pipe or ground rod. Oftentimes they just put a green > copper jumper wire between the "declared" neutral terminal on the > transformer and the transformer attachment screw in the panel and they > use the steel panel backplane for "ground". If you are using a single > point ground just run a green ground wire from the neutral terminal on > the transformer and the single point ground in the panel. > > Dave > > On 1/1/2016 7:02 AM, John Thornton wrote: > > Hi Jon, > > > > So tie say the 48v side to ground to create the neutral? I attached > > the drawing of what I have so far on the VFD side. > > > > Happy New year to you and I hope you stayed dry during the recent > > monsoon we got. > > > > JT > > > > On 12/31/2015 7:16 PM, Jon Elson wrote: > >> On 12/31/2015 03:24 PM, John Thornton wrote: > >>> I went and checked the control transformer and one side is 48v to > >>> ground > >>> and the other side is 79v to ground. I guess I was confused by that. > >>> > >> Do you have a ground connected to that winding? If not, > >> then the capacitance of that winding to other windings and > >> the core will set what AC potential you get at each end. > >> I'm guessing you have a totally floating secondary, and this > >> adds up to 127 VAC, which sounds right for a nominal 120 V > >> output. You can tie one end of the winding to frame ground, > >> establishing a new neutral in the cabinet for the computer, > >> etc. loads. > >> > >> Jon > >> > >> ---------------------------------------------------------------------------- -- > >> > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > ---------------------------------------------------------------------------- -- > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > ---------------------------------------------------------------------------- -- > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------ Message: 7 Date: Fri, 1 Jan 2016 11:13:52 -0800 From: "John Dammeyer" <jo...@autoartisans.com> Subject: Re: [Emc-users] Rewiring the BP To: "'Enhanced Machine Controller \(EMC\)'" <emc-users@lists.sourceforge.net> Message-ID: <09d301d144c8$8e9b37a0$abd1a6e0$@autoartisans.com> Content-Type: text/plain; charset="us-ascii" (Reposted with link to pdf fixed) Here's what I did for my SouthBend Lathe. Not run with CNC but with my Electronic Lead Screw. http://www.autoartisans.com/Lathe/SouthBendPower.pdf http://www.autoartisans.com/Lathe/ControlBox.jpg http://www.autoartisans.com/Lathe/ControlBoxInside.jpg The System Relay is wired as a latching relay that stays ON until ESTOP is hit. Both the coolant pump switch and Spindle Start relay must be off before the Relay is energized. An ESTOP disconnects power to the dangerous voltages but leaves the ELS powered. Since I fed this box with 220VAC there is no neutral and I used a transformer to power a split duplex outlet. One side of the 120VAC is bonded to Earth. I haven't had any electrical noise problems. But I have also not yet wired the RS232 port of the ELS to the VFD for speed control. John Dammeyer > -----Original Message----- > From: Dave Cole [mailto:linuxcncro...@gmail.com] > Sent: January-01-16 8:14 AM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Rewiring the BP > > > Yes, > > Anytime you have a 120 volt source for computer, misc power etc, you > need to declare one side of the 120 vac winding the neutral (white wire) > and tie that terminal to the machine frame. > It similar to what is required at the service entrance of your house. > The neutral is always tied to the ground at the entrance box. > Oftentimes they drive a screw through the neutral buss bar in the > service entrance box into the box sheetmetal and then tie a green or > bare copper ground wire to the same neutral buss bar and run that to a > metal water pipe or ground rod. Oftentimes they just put a green > copper jumper wire between the "declared" neutral terminal on the > transformer and the transformer attachment screw in the panel and they > use the steel panel backplane for "ground". If you are using a single > point ground just run a green ground wire from the neutral terminal on > the transformer and the single point ground in the panel. > > Dave > > On 1/1/2016 7:02 AM, John Thornton wrote: > > Hi Jon, > > > > So tie say the 48v side to ground to create the neutral? I attached > > the drawing of what I have so far on the VFD side. > > > > Happy New year to you and I hope you stayed dry during the recent > > monsoon we got. > > > > JT > > > > On 12/31/2015 7:16 PM, Jon Elson wrote: > >> On 12/31/2015 03:24 PM, John Thornton wrote: > >>> I went and checked the control transformer and one side is 48v to > >>> ground > >>> and the other side is 79v to ground. I guess I was confused by that. > >>> > >> Do you have a ground connected to that winding? If not, > >> then the capacitance of that winding to other windings and > >> the core will set what AC potential you get at each end. > >> I'm guessing you have a totally floating secondary, and this > >> adds up to 127 VAC, which sounds right for a nominal 120 V > >> output. You can tie one end of the winding to frame ground, > >> establishing a new neutral in the cabinet for the computer, > >> etc. loads. > >> > >> Jon > >> > >> ---------------------------------------------------------------------------- -- > >> > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > ---------------------------------------------------------------------------- -- > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > ---------------------------------------------------------------------------- -- > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ---------------------------------------------------------------------------- -- _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------ ------------------------------------------------------------------------------ ------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users End of Emc-users Digest, Vol 117, Issue 7 ***************************************** ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
