[GTALUG] mysterious restarts

D. Hugh Redelmeier hugh at mimosa.com
Wed Jun 15 22:02:23 EDT 2016


| From: Alvin Starr via talk <talk at gtalug.org>

| Actually the static power loss goes down as the voltage goes up.
| 
| So for example if the streetcar draws 600W at 600V then the current draw is 1A
| but at 750V the current draw is 0.8 amps.
| The overhead line losses are directly proportional to the current flowing
| through them so there would be roughly a 20% decrease in power loss in the
| wires.
| 
| With an electrical bill like the TTC must have a 20% decrease would be a
| significant amount of money.

I'm no EE, but here's my guess.

Energy losses are proportional to the square of the current and thus
the square of the inverse of the voltage.
	(750/600)^2 = 1.5625
So they would save more than a third of the transmission losses.

I have no idea how much their transmission losses are as a proportion
of the electrical power used.


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