Originally Posted By: Shannow
* the above do some really weird things, e.g. if you have a high voltage line that runs a hundred miles, and is energised at one end, the "loose" end that you want to connect the next town to can have much, much higher voltage than is allowed (Ferranti effect), meaning that the other end can't be energised...
Had to look that one up:
http://en.wikipedia.org/wiki/Ferranti_effect
Sounds like the transmission line is long enough to act as, well, a transmission line, and actually does a voltage step up. Always wondered if the power lines did run into those effects too or not. I guess they do!
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Looking at the link:
https://uk.answers.yahoo.com/question/index;_ylt=AibSLNiBCjSZBLJRw5AXA2cgBgx.;_ylv=3?qid=20070624035420AAgWBQ6
I see this:
Quote:
after world war two, European regulators established 240V(50 Hz, to fit better with the metric system)
Which I don't understand. 50 is a nicer number to work with, but if it was me I'd just pick a nice binary number, so one could divide using simple counters to make 1Hz for clocks and other things needing a clock reference. 32 is probably too slow (may see flicker in light bulbs), 64 would be a good number, and 128 probably not too bad, although skin effect would likely mean yet even more power loss on the really long transmission lines.
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I believe the UK (Europe too?) has lower voltage bulbs for drop lights etc. Want to say 55V. One nice feature, not so important today, is that lower voltage bulbs use thicker filaments which are more shock resistant.
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I find it somewhat ironic today that, for anything electronic, and for an increasing number of even large electric motors, the first thing that happens to the power coming into the item is rectification. Generate high voltage DC, then buck to whatever DC level is required. Chop as necessary to run PWM to a motor even. Means that dirty DC power ought to run most anything. Anything not using a simple AC motor across the line, that is.
Yes, I realize that AC works well with simple step up/down transformers. [But AC lines do suffer from skin effect, so a DC line ought to have less line losses. Worse arc issue though, no self quenching available when the voltage crosses zero, so harder on relays. Not sure about impact on solid state relays though.] But sometimes I wonder if Edison isn't have a last laugh at times. Even if he was simply wrong in his arguments.