The stator windings of induction motors also make pretty good inductors. Can be had for scrap value if you're lucky
Sent from BlueMail On 5 Mar. 2018, 01:16, at 01:16, Lee Hart via EV <ev@lists.evdl.org> wrote: >John Lussmyer via EV wrote: >>>> Would a "bad boy" full wave 3 phase rectifier work? (I'd probably >need to adjust the voltage output of the generator.) > >> Figuring out the inductor size might be a bit difficult, but >hopefully not TOO critical. >> I'm unlikely to need more than about 30KW out of this continuously. > >It's not critical. The more the better (up to the point where the >inductor becomes impractically big/heavy/expensive, or its resistance >adds too much loss/heat). > >The inductor's job is to spread out the current spikes at each AC peak. > >32kw at 320vdc is 100 amps average. With no inductance, the current is >liable to be 400a spikes for 1/4 of the time. That will put a real >strain on the diodes and wiring. > >The more inductance you add, the smoother the current becomes. The >peaks >go down, and fill in the zero-current valleys. > >If you manage to get too much inductance (which would probably take an >inductor too big to lift), the output current essentially becomes DC. >The current in each of the 3-phase windings becomes a 33% on-time >square >wave. > >Note: That big inductor will have a hell of an inductive "kick" if >something tries to interrupt the DC output current. A switch, fuse, or >circuit breaker on the DC output will arc like mad if it opens while >charging at 100A! > >An old arc welder transformer should work as an inductor. Disconnect or > >remove the primary and rectifier, and use the high-current secondary as > >your inductor. > >>> If you want to fully regulate the output voltage and current, three >of >>> the diodes in the bridge could be replaced with SCRs, and phase >>> controlled. Copy a classic circuit from an SCR manual, or use your >>> favorite microcontroller and program it yourself. >> >> And also thanks for giving the ONLY useful answer that didn't boil >down to "go buy a 30KW 3 phase hi-voltage charger". > >You are most welcome! Though my solutions are often on the crude / old >tech side, that is because it's more likely that people can actually >*do* them. Wonderful high-tech solutions are great on paper; but often >never get implememted. > >In your case, I know you are a great programmer; so a solution that >includes a micro is not going to be a roadblock. That's the part you >like! :-) > >-- >You never change things by fighting the existing reality. To change >something, build a new model that makes the existing model obsolete. > -- R. Buckminster Fuller >-- >Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com >_______________________________________________ >UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >http://lists.evdl.org/listinfo.cgi/ev-evdl.org >Please discuss EV drag racing at NEDRA >(http://groups.yahoo.com/group/NEDRA) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20180305/c9efcec2/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
