Dave, Yes I want a 5hp vfd with single phase input and that is why i am interested in the gohz GK3000-2S0037 @ $294. On amazon there are some even cheaper @$132 but there is no on line manual and i don't think a 5 hp single phase input drive can be made that cheap.
I read the article you referenced https://www.precisi on-elec.com/derate-three-phase-vfd-for-single-phase-power/ but I don't agree with it because he is simply scaling the input current by the 3 phase to single phase conversion constant of square root of 3 or 1.73. This holds true for the input current but not the internal DC bus capacitor RMS ripple current which causes capacitor heating. On the other hand there is a huge difference between occasional hobby use and industrial use so maybe I shouldn't be so finicky. John Figie On Jan 2, 2018 8:03 AM, "Dave Cole" <[email protected]> wrote: > Except that he needs a 5 hp single phase inverter. Those are a little > harder to find and a lot more expensive... near $1000 for this AC Tech > Drive. > > https://www.wolfautomation.com/products/ac-drives/ac-drive- > 5hp-208-240vac-1-3-phase-input > > Phase converters do have some phase current balance issues but for low > tech - I just want to run the machine - they are hard to beat unless you > are running the machine a lot or at a constant full load. I have a rotary > phase converter built with a 10hp motor 15+ years ago and it will power a > 10 hp Quincy two stage air compressor at slightly reduced pressure. I > probably put about $250 into that phase converter 15 years ago. Good > motor run caps are the key. Those can be bought off Ebay and Surplus > Center, etc. > > There is a small down the road that manufactures steel stakes for the Army > Corp of engineers and landscape contractors in large quantities and he has > an assortment of small punch presses and the entire shop runs off single > phase power with a phase converter. So it can be done. Sometimes low tech > is enough and if you don't need variable speed it can work well. > > Dave > > On 1/1/2018 7:58 PM, Gregg Eshelman via Emc-users wrote: > >> Or just get a proper single phase to three phase VFD and do the job >> right. For under $200 you can get a 230V 1PH in drive that'll run up to a >> 3HP 3PH >> https://www.wolfautomation.com/products/ac-drives >> >> On Monday, January 1, 2018, 10:49:12 AM MST, John Figie < >> [email protected]> wrote: >> All, >> >> Thanks for your replies. >> >> My real question was to see if anyone had used GOHZ or some other cheap >> drive. I currently run all my machines from a home made rotary phase >> converter. It works pretty well but does not produce the best 3 phase. >> Yes I know you can use capacitors to adjust the outputs which I have. The >> rotary converter has been running in my shop for about 15 years. I have a >> hydraulic automatic surface grinder that does n't like being run from the >> phase converter. The pump motor overheats when run from my rotary >> converter, I think maybe this is because the motor runs near full load. >> >> I know I can use a larger drive and derate it to use on single phase >> power, >> but that seems like a much more expensive option.<clip> >> ----------------------------------------------------------- >> ------------------- >> Check out the vibrant tech community on one of the world's most >> engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
