On Monday 16 July 2018 10:22:28 andy pugh wrote: > On 16 July 2018 at 14:37, Gene Heskett <[email protected]> wrote: > >> While on the subject of voltage-increasing, apparently it is > >> possible to re-wire the input stage of a 440V VFD into a doubler > >> circuit to allow it to run (derated) off of 240V. > >> https://en.wikipedia.org/wiki/Voltage_doubler#Delon_circuit > > > > Due to the physical size of the capacitors involved, I'd think it > > impossible to shoehorn it into the 440 volt VFD. > > The idea is to re-arrange the existing input diodes and capacitors > into a doubler arrangement. > > But you need to derate because caps sized for 3-phase full-wave are > now seeing single-phase half-wave rectification.
That derate would exceed 50% I'd imagine. And would nominally halve the life of the caps. Not to mention the diode peak currents are now much higher. Sounds like a questionable lifetime result. Would it not be cheaper over the decades to buy the correct stuff, or even pay for a three phase service upgrade? If all 3 phases are on your street, not the case for me by at least a mile of new wire, but if it is, conversion costs shouldn't exceed a 4 digit cost. Probably a good thing I am only in this as a hobby. So I pay for this stuff piecemeal, as needed to get some capability I don't have now. The "would be nice" category, but it doesn't pay the bills. ;-) -- 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> ------------------------------------------------------------------------------ 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
