On 1/28/2011 11:19 AM David Nebenzahl spake thus:

The other fallacy here is that because we don't actually use 2-phase
electrical power, there cannot be any such thing as 2-phase power. It is
true that two phase power (0° - 180°) is not very useful; that's why we
don't have any 2-phase motors. But technically, a system with two legs
of 0° and 180° is, in fact, a 2-phase system.

Actually, there is at least one application which depends on there being
2 phases in ordinary residential power distribution panels: the
so-called Edison circuit. This is where two circuits are run with
separate "hots" and a common neutral, where the neutral conductor is the
same size as the hots.

The only way this can work is if the two circuits are separate phases
(in this case, 180° apart), so that the currents cancel in the common
return conductor.

Apart from this, we wouldn't care if the two legs of the power company's
step-down transformer delivered the same phase of power (just give us
the juice! who cares about the phase?).


--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.