On 27/07/14 21:08, Nightjar "cpb"@ insert my surname here wrote:
On 27/07/2014 20:57, wrote:
AC for simple long-distance transmission...

Except for underwater cables, where it can cause unacceptable
transmission losses.


Actually the ONLY - but overwhelming - advantage of AC is that it can
be transformed in terms of voltage by Victorian technology.

The disadvantages a

- it radiates
- it suffers capacitative current flow that induces extra losses in the
resistive cables
- it suffers out of phase losses when ringed over very long distances -
continent sized.
- it causes muscle spasms in shock situations.
- it it isn't especially useful in motor situations.

Now that we have reasonably efficient DC to DC converters its is likely
it won't be used that much more outside national scale grids..

All medium length underwater and all long length transcontinental inks
are now DC

USB style 5V DC power is becoming a de facto standard in low power home
situations.




--
Everything you read in newspapers is absolutely true, except for the
rare story of which you happen to have first-hand knowledge. €“ Erwin Knoll