The question about transformers was if the transformer could be placed BETWEEN the VFD and the motor. Of course the VFD does not care if there is a transformer between it and the utility power.
The problem being discussed here is that the motor wants 440 volts and only 220 is available. The only reasonable solution is to use a VFD that outputs 440 volts. Using a transformer between a 220 output VFD and the motor would require a hyper-expensive custom designed transformer. No one would pay for such a thing, so it is better to buy a 440 volt VFD. The other option is to build a DIY VFD. They are not "rocket science" On Fri, Jun 18, 2021 at 7:52 AM Jon Elson <[email protected]> wrote: > On 6/17/21 8:45 PM, Gregg Eshelman via Emc-users wrote: > > Everything I've read on VFDs says do not feed them from a transformer. > > WHY? Every VFD is being run from a transformer! What's > that thing up on a pole beside your house, or on a pad > behind your industrial shop? Yes, it is a transformer. > > There really is no reason to NOT use a suitable transformer > to provide the correct voltage to a VFD. > > First, you need to be sure your VFD can run off single-phase > power. If not specifically rated for it, then up-sizing the > VFD for 1.5 to 2X the motor rating will usually be fine. > > > Nor can you put a transformer between the VFD and the motor. > Yes, this is generally correct. > > Most of them say *nothing* should be between the VFD and the motor, > direct connection only. The one on my 1943 Monarch 12CK lathe recommends a > noise filter on the input side to prevent noise feeding back into the line > from the VFD from getting to other stuff on the circuit. > Your 1943 Monarch does not have a VFD. The 10EE lathes had > two different schemes, depending on year. The old ones had > an AC motor-driven DC generator, the later ones (1960 or so) > had a thyratron drive for a shunt-wound DC motor. (Or, > maybe you are using a VFD to provide 3-phase power to the > motor-generator.) > > Jon > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
