> From: Lee Hart <[email protected]> > > All these problems are solvable if you throw enough engineering and > money at them. But it's not goiong to lead to a cheap simple system. > > That's why everyone avoids using the propulsion wiring itself to carry > data. It's far cheaper and more reliable to run separate wires for data.
I agree there doesn't seem to be much practical advantage to re-using the traction power lines. As a minimum, you'd need a filter at the controller. Caps are cheap, but a 500A choke is going to cost more than the #18 (or smaller) wire you'd have to run if you use dedicated wire. A huge ferrite bead might be enough for VHF and up. That's why the whole "wideband over power line" never got out of the starting chute. You'd need a high-frequency bridge over every transformer in the system. I can see ten of them out my window — in a rural, low-density area! I did play with the X-11 home power control protocol some decades ago, and built a Heathkit powerline-carrier intercom as a kid. But the grid wideband response is tremendously difficult to characterize, which I'd expect the traction bus to be, too. I've seen TDR graphs of different power line situations at different frequencies — it is totally unpredictable what characteristic impedance you can count on! The best scheme would probably be diversity spread spectrum, which ain't cheap. :::: We need an energy policy that encourages consumption. -- George W. Bush <http://www.lmgtfy.com/?q=George+W.+Bush> :::: :::: Jan Steinman, EcoReality Co-op <http://www.ecoreality.org/> :::: _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
