Very good idea! And if you want to learn something, this guy will be the right one to ask your questions to. He will know local regulations and hopefuly tell you what is doing, just ask a few holes in his stomach, as we say.
Gene, you made some experience the hard way (no envy), which I didn't have in just this manner, but I can remember e few instances where I found myself on the floor, too, without knowing why I laid down... Peter Brian May schrieb: > 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 <ghesk...@wdtv.com> 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 <e...@dc9.tzo.com> 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<bmihu...@hulkster.net> >>>>>> >> 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 >>>>>>>> Emc-users@lists.sourceforge.net >>>>>>>> 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 >>>>>>> Emc-users@lists.sourceforge.net >>>>>>> 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 >>>>>> Emc-users@lists.sourceforge.net >>>>>> 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 >>>>> Emc-users@lists.sourceforge.net >>>>> 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 >>>> Emc-users@lists.sourceforge.net >>>> 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 >>> Emc-users@lists.sourceforge.net >>> 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 >> Emc-users@lists.sourceforge.net >> 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
