On Mon, 19 Aug 2013 13:55:57 -0400, Bill
wrote:
Swingman wrote:
On 8/19/2013 10:52 AM, Markem wrote:
On Mon, 19 Aug 2013 09:45:19 -0500, Swingman wrote:
Markem wrote:
On Mon, 19 Aug 2013 09:00:09 -0500, Swingman wrote:
Markem wrote:
On Mon, 19 Aug 2013 06:54:36 -0500, Swingman wrote:
Nope.
In the US the transformer for most residential power taps one of
the 3
phases in the power distribution system, which is why it is called
single phase, even though there are 2 hot legs.
The transformer center tap on the pole is grounded and also
connected to
a wire called neutral. This provides two output voltages
relative to
ground or neutral. Each is 120 V, but they are 180 degrees out
of phase
with respect to each other.
Your understanding of electrical things is not very good. I have
many
years as an electronic tech. I have tested with an oscilloscope your
theory and proved it wrong. The two legs of a 240V are in phase.
But in the end it really does not matter because everthing
electrical
will still work as long as it ain't broke.
Mark
Then you should know the difference between electric and
electronic. 
I do, do you? 
You just think you do ... read the second sentence and weep:
http://en.m.wikipedia.org/wiki/Split_phase
The two halves of the transformer are 180 degrees apart, not the
signal. Question what do you get when you add 120 and -120?
Yes, one takes the difference (not does addition). Although I'm
surprised the 2 halves are 180 degree apart. A relative told me there
were 3 hots at the pole (but he has a factory background, where 3-phase
in the norm).
The main AC distribution system is indeed three phase, with the phases
120 degrees apart. However, most residential areas only get one of
the three high voltage phases, and that is stepped down to 120/240V in
a single phase transformer. The center of the 240 volt secondary of
that transformer is grounded, and becomes the Neutral. The two ends
of the secondary become the two 120V "hots". Because they come from
opposite ends of the 240 V winding, there is 240 V between them. The
two hot wires can be described as 180 degrees out of phase (although
this description upsets some people). You could also say that one hot
wire is inverted relative to the other - when wire A is at +120V and
rising, wire B is at -120V and falling, so you will measure 240V
between the hot wires.
--
Peter Bennett, VE7CEI Vancouver BC
peterbb (at) telus.net
Vancouver Power Squadron:
http://vancouver.powersquadron.ca