On Sunday 14 June 2015 10:54:57 Dave Cole wrote: > Gene, > > Try looking for a Nema 48 AC motor. They are almost an inch smaller > in diameter.
That makes perfect sense. But no search hits until I drop it to Nema 42. > Also, there are some metric frame motors that are common in Europe > that are also smaller in diameter than a Nema 56. > > http://kurz.com/wp-content/uploads/2014/09/Baldor-NEMA-Frame-Chart.pdf > > http://www.engineeringtoolbox.com/nema-electrical-motor-frame-dimensio >ns-d_1504.html > > Dave > I think one of the things that is confusing me is when you or I think 3 phase, we are thinking of a hard armature that is in fact a p.m. So while it may have a phase lag due to loading, it is in fact synchronous. Such a motor can be driven at stump pulling speeds with full torque available just by dropping the drive frequency, and they will do it without excessive heating if the invertor is current regulated. Fading only when the rpms doesn't generate a cooling air flow. But for the average guy peddling what he found on ebay, he has no clue how to tell us that THIS motor is in fact an induction motor, and the output rpms MUST lag the frequency because that is what generates the currents in the armature that make it run. So how do we discern the induction motor,totally unsuitable for vfd drive except near is design rpms, from the synchronous motor at home on a vfd drive? Example: Doing a search for a 3 phase motor, the complete first 50 hits are all induction, none claim to turn as synchronous speeds. All "slip" some as much as 75 rpm from 1800. 1800 or 3600 on 60hz would indicate one we might be able to use. > On 6/14/2015 10:16 AM, Gene Heskett wrote: > > On Sunday 14 June 2015 05:06:22 andy pugh wrote: > >> On 14 June 2015 at 02:38, Gene Heskett <ghesk...@wdtv.com> wrote: > >>> It does look good, but where can I get an adaptor to mount that > >>> 56C frame on the GO704? Or is that my first project, making one? > >>> ;-) > >> > >> What is the existing motor mount? > > > > About an inch smaller OD than a 56C. > > > >> I adapted my Mini-Mill to a standard 3-phase motor: > >> https://picasaweb.google.com/lh/photo/Dk3wsS9o7XJ-N2kfUnESDtMTjNZET > >>Ymy PJy0liipFm0?feat=directlink > >> > >>> At $116 + ship, looks good also. Needs a modbus circuit from lcnc. > >>> Who has that hardware? > >> > >> Just because you can use Modbus it doesn't mean that you must use > >> Modbus. Those VFDs all accept analogue voltage, potentiometer and > >> current-loop too. > > > > That greatly simplifies that, 5i25 pwm out driving a SpinX1 which I > > have. > > > > Cheers, Gene Heskett > > --- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus > > > ---------------------------------------------------------------------- >-------- _______________________________________________ > 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> ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
