Brian, If you work at some industrial facility or know someone who does, try and find an industrial electrician to help you out. Oftentimes they will not be a "licensed electrician" as they are not a contractor. They may, or may not have a journeyman's card, depending on their background.
You do not want a guy that wires houses even if he is licensed, as he will likely know almost nothing about machine wiring. Dave On 11/11/2011 12:04 PM, Brian May wrote: > Yes, you are probably right, I will look for a local professional guy to > come and get things going. At least I have an idea of what is > happening... > > Thanks for the advice > > On Fri, Nov 11, 2011 at 10:54 AM, gene heskett<[email protected]> wrote: > > >> On Friday, November 11, 2011 11:28:02 AM Peter Blodow did opine: >> >> >>> Brian, >>> looking at your questions I get the feeling that you are a bloody >>> beginner as far as power electricity is concerned. I get the scares >>> imagining what you could possibly do to yourself and others, >>> experimenting with your mains supply. It would be much safer for you and >>> would calm my nerves (and apoparently other's, too) if you'd call a >>> local electrician to wire the basic supply of your machinery or what you >>> have. It's worth your life's value. Please get yourself some sound >>> advice! This is not electronics where a fault only results in a burned >>> up transistor or so. >>> >> I've been following this thread, debating if I should jump in, but now that >> Peter has said it, I concur heartily with his advice. >> >> Its easy enough to be crispy critter'd around mains power, I've damned near >> done it to myself at least 3 times in my work around tv stations where we >> may be the local power companies largest customer. 2nd degree burns on both >> arms& the at the instant bare chest, will take ALL the starch out of you >> for a few days, and likely lay you up with the shingles for a month or >> more. Been there, done that, it will totally redefine your personal pain >> threshold, upwards. No one needs that but somehow I kicked loose and >> survived. >> >> Simply put Brian, if you need to ask these questions, then get a licensed >> pro who is intimately familiar with the local codes and let him do it. We >> aren't there and in some cases in this thread are trying to be helpful with >> inadequate information and almost zero knowledge of local codes. >> >> Old buildings with grandfathered in electrical supplies can be legal, and >> lethal. >> >> >>> To make it clear: grounding is the up and down of electrical power >>> application. Imagine only a little high resistance insulation fault in >>> the primary of your local high voltage transfomer - if the secondary >>> would not be grounded in some way, in this case you could easily >>> experience 10 or 20 kV on your home outlet.... In case the secondary is >>> ground referenced by connecting the center tap of the secondary windings >>> to ground, this fault might not even be noticed! Floating potentials are >>> a highly dangerous thing, never leave any circuit unreferenced to >>> ground! >>> >>> Peter Blodow >>> >>> Brian May schrieb: >>> >>>> Sent from my iPod >>>> >>>> On Nov 10, 2011, at 10:30 PM, Dave<[email protected]> wrote: >>>> >>>>> Usually bigger 3 phase machines being fed with 480 volts or so will >>>>> only have the 3 phases run to the machine without a neutral wire. >>>>> >>>>> The reason being that Line to Neutral on a 480 volt system is 277 >>>>> volts and that is not very useful for anything other than lighting. >>>>> >>>>> To get 120 VAC, two of the phases will be tapped (480 volts) and that >>>>> will be run to a step down transformer. >>>>> One the secondary side of the transformer, one leg of the >>>>> transformer will be declared the hot line, and the other leg will be >>>>> declared the neutral. >>>>> The neutral will be bonded to the ground close to the transformer. >>>>> The hot line is fused. That will establish a proper 120 VAC >>>>> circuit off the 3 phase input power. >>>>> >>>> What is meant by "bonded to the ground"? Does that mean connecting >>>> the nuetral leg of the transformer to the ground? If so, why use the >>>> transformer at all when i can just go from a leg to ground? >>>> >>>> >>>>> You could run a separate single phase feed into the existing 3 phase >>>>> power panel, but then you would have power being fed into one panel >>>>> from two different sources and that gets tricky from a safety >>>>> standpoint. I try and avoid doing that whenever possible. >>>>> Generally when you pull the disconnect switch on a machine panel you >>>>> want to kill all power in the panel for safety. >>>>> >>>>> A lot of machine builders are now avoiding 120 volt power system in >>>>> their machines entirely. They do that by using DC power supplies >>>>> that can accept high voltage input power directly. >>>>> >>>>> You can buy 3 phase input power supplies that will accept up to 600 >>>>> VAC and produce 24 VDC. Most of the big power supply makers sell >>>>> them. >>>>> >>>>> Dave >>>>> >>>>> On 11/10/2011 10:27 PM, Brian May wrote: >>>>> >>>>>> Ok that makes sense. >>>>>> >>>>>> Just out of curiosity, How do other machines do it. Our other cnc >>>>>> machines only have the 3 lines and earth ground running into >>>>>> them... >>>>>> >>>>>> Sent from my iPod >>>>>> >>>>>> On Nov 10, 2011, at 9:01 PM, Brian Mihulka<[email protected]> >>>>>> >> wrote: >> >>>>>>> On 11/10/2011 08:50 PM, Brian May wrote: >>>>>>> >>>>>>>> This is probably an easy question for alot af the people on the >>>>>>>> list. >>>>>>>> >>>>>>>> I have 3 phase power going to my vfd on my machine. I want to the >>>>>>>> use that same power to power all the 120 single phase components. >>>>>>>> (the dc power supply for the steppers and varios other motors. ). >>>>>>>> This way i only need 1 plug >>>>>>>> >>>>>>>> I have been reading and people say i can go from 1 leg to a >>>>>>>> nuetral or leg to leg. I do not have a nuetral line so my >>>>>>>> question is will it be ok to go from leg to leg for the 120 >>>>>>>> single phase? Or is there some other component i need? >>>>>>>> >>>>>>>> Thanks >>>>>>>> Brian >>>>>>>> >>>>>>>> Sent from my iPod >>>>>>>> ------------------------------------------------------------------ >>>>>>>> ------------ RSA(R) Conference 2012 >>>>>>>> Save $700 by Nov 18 >>>>>>>> Register now >>>>>>>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>>>>>>> _______________________________________________ >>>>>>>> Emc-users mailing list >>>>>>>> [email protected] >>>>>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>>>>> >>>>>>> If its 3 phase 208, one leg to any other leg will give you 208. >>>>>>> You have to have the neutral to get 120 from any leg. You should >>>>>>> get 120 from any leg to ground but it wouldn't be up to code. >>>>>>> >>>>>>> Brian >>>>>>> >>>>>>> ------------------------------------------------------------------- >>>>>>> ----------- RSA(R) Conference 2012 >>>>>>> Save $700 by Nov 18 >>>>>>> Register now >>>>>>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>>>>>> _______________________________________________ >>>>>>> Emc-users mailing list >>>>>>> [email protected] >>>>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>>>> >>>>>> -------------------------------------------------------------------- >>>>>> ---------- RSA(R) Conference 2012 >>>>>> Save $700 by Nov 18 >>>>>> Register now >>>>>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>>>>> _______________________________________________ >>>>>> Emc-users mailing list >>>>>> [email protected] >>>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>>> >>>>> --------------------------------------------------------------------- >>>>> --------- RSA(R) Conference 2012 >>>>> Save $700 by Nov 18 >>>>> Register now >>>>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>>>> _______________________________________________ >>>>> Emc-users mailing list >>>>> [email protected] >>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>> >>>> ---------------------------------------------------------------------- >>>> -------- RSA(R) Conference 2012 >>>> Save $700 by Nov 18 >>>> Register now >>>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>>> _______________________________________________ >>>> Emc-users mailing list >>>> [email protected] >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>> >>> ------------------------------------------------------------------------ >>> ------ RSA(R) Conference 2012 >>> Save $700 by Nov 18 >>> Register now >>> http://p.sf.net/sfu/rsa-sfdev2dev1 >>> _______________________________________________ >>> Emc-users mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> >> >> Cheers, Gene >> -- >> "There are four boxes to be used in defense of liberty: >> soap, ballot, jury, and ammo. Please use in that order." >> -Ed Howdershelt (Author) >> My web page:<http://coyoteden.dyndns-free.com:85/gene> >> They call them "squares" because it's the most complicated shape they can >> deal with. >> >> >> ------------------------------------------------------------------------------ >> RSA(R) Conference 2012 >> Save $700 by Nov 18 >> Register now >> http://p.sf.net/sfu/rsa-sfdev2dev1 >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> > > > ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
