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. Some drives have missing phase detection that I could probably trick with some kind of AC input. I think the concerns for me are that the input diode bridge will see the input current distributed among 4 diodes but instead of 6. Also the conduction angle of the diodes will be longer since all of the input current must be supplied from the single phase rather than overlapping phases. Finally the stress on the DC bus capacitors will be much higher due to the higher DC bus ripple. This bus capacitor RMS ripple current degrades the capacitors due to internal heating. Now since this is a lathe spindle and I am a hobbyist how often will I really need to load the machine to 5hp? Probably not very often. Also I can set the acceleration/deceleration to a conservative value to reduce the peak currents. Additionally I think I could replace my rotary phase converter (which is kind of noisy) with the VFD which will produce a different kind of noise (electrical) but It will be quiet. My motivation for asking about GOHZ is that I just discovered them and they have a $294 drive rated for single phase input so I would presume that the additional stress was considered in the design. Automation direct does not list any VFDs of 5hp or higher rated for operation from a single phase. Here is what I have found so far listed on a spreadsheet. https://docs.google.com/spreadsheets/d/1YS-QKbJIlBYDSPdWAelA6ZF0zbS30HrHnqE02-opSRI/edit?usp=sharing If anyone knows of other options please let me know. John Figie On Mon, Jan 1, 2018 at 11:09 AM, Dave Cole <[email protected]> wrote: > I have heard that sometimes you can get around that by putting a motor > run capacitor between one of the live phases and the unconnected input > power terminal. > That can sometimes trick the drive into thinking that it has power at all > of the terminals. > > Back when VFDs were very expensive the way to do this was with a static or > rotary phase converter. > I have a 5 hp 3 phase motor on an old turret lathe spindle that I run off > a rotary phase converter that I put together a long time ago. It > works. You can find how to instructions on how to build one on the > net. You will need a 3 to 10 hp 3 phase motor as a base device for the > converter. > > You can also make a static 3 phase adapter for your existing motor simply > by adding some capacitors to "power" the third phase. Info for that is > also on the net. > > Dave > > > On 1/1/2018 3:46 AM, Nicklas Karlsson wrote: > >> Usually there is a diode rectifier at the input but I guess they also >> measure voltage and refuse to run then to low so experience is important. >> >> On Sun, 31 Dec 2017 18:45:44 -0600 >> John Figie <[email protected]> wrote: >> >> I have a 5 hp 240V 3 phase induction motor that is for a lathe spindle. I >>> only have single phase 240V power. It seems that most 5 hp vfds do not >>> allow single phase input. I found this: http://www.gohz.com/5hp-vfd >>> Does anyone have experience with GOHZ or other affordable 5 hp drives >>> that >>> will run on single phase? >>> >>> John Figie >>> ------------------------------------------------------------ >>> ------------------ >>> 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 > ------------------------------------------------------------------------------ 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
