AC motor voltage conversion?

In article ,
(Robert Bonomi) wrote:

180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

240V single phase, commonly supplied to single family dwellings, has a
center tap and two hot leads which are 180 degrees out of phase to supply
higher powered items such as air conditioning and electric stoves. In
addition, approximately half of the lower powered items, such as lights and
the refrigerator, are powered by each of the two legs to the center
tap--which is approximately ground potential.

Peter

Morgans wrote:
"John Ammeter" wrote in message
...
Why does everyone think the voltage is 110/220??

If that actually was the voltage you had in your house you'd be very unhappy.
The nominal voltage is 118/236 with a +/- 5% range so you can see that 110/220
is actually outside the acceptable range.

Well, duh, John!

Why is a car called a car?

Short for carriage.

Dan

In article ,
"Peter Dohm" wrote:


180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

240V single phase, commonly supplied to single family dwellings, has a
center tap and two hot leads which are 180 degrees out of phase to supply
higher powered items such as air conditioning and electric stoves. In
addition, approximately half of the lower powered items, such as lights and
the refrigerator, are powered by each of the two legs to the center
tap--which is approximately ground potential.

Ahhh! But where does the 240 come from?
Does it not come from two of the three legs of a Y or Delta?
These are square root and cube root functions.
If they were 180 out of phase, it would cancel.

"T o d d P a t t i s t" wrote in message
...
| john smith wrote:
|
|
| Ahhh! But where does the 240 come from?
| Does it not come from two of the three legs of a Y or Delta?
|
| It doesn't matter where the 240 comes from, it matters what
| the phase of each wire is relative to some reference. The
| US (and Europe, but at twice the voltage) use a 3-wire,
| single-phase, mid-point neutral distribution system for most
| residential loads. If you use the neutral as the reference,
| then there are two opposite phase wires or split phases. If
| you use the opposite wire as the ref, then there is a single
| phase 240 volt signal.
|
| Commercial sites receive 3-phase power, not single phase.
| The voltage difference between two of the three legs in that
| system is 208 volts, not 240 volts
|
| These are square root and cube root functions.
|
| No they are not - they are trig functions depending on phase
| angle.
|
| If they were 180 out of phase, it would cancel.
|
| Phase depends on the reference. You can ignore the neutral
| and just see it as a single phase 240 volt system using
| either hot lead as the reference. If you prefer, you can
| think of one hot lead as being the reference, the neutral as
| having a 120 volt signal on it and the other hot lead as
| having a 240 volt signal in phase with the 120 volt signal
| on the neutral.
|
|
|
|
|
| --
| T o d d P a t t i s t
| (Remove DONTSPAMME from address to email reply.)
|
| Make a commitment to learn something from every flight.
| Share what you learn.

Came across this:

If you have three phase (Y or Wye, which is fairly commonly provided to
businesses or industries but not common in homes) electricity, you can
get a ``sort of'' 240 volt circuit out of it by running between any two
of the three phases. The phase difference is only 120° instead of 180°
so one ends up with only 208 VAC or so between the wires. This is enough
to run most 240 VAC devices simply because the manufacturers aren't
fools and know that Y/Wye supplies are fairly common. This is also true
for a lot of computer equipment that requires 240 VAC (like some racks
or uninterruptible power supplies (UPS) or some big-iron computers).

Taken from this site:
http://www.phy.duke.edu/~rgb/Beowulf...ok/node60.html

--
Jarhead





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180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

240V single phase, commonly supplied to single family dwellings, has a
center tap and two hot leads which are 180 degrees out of phase to
supply
higher powered items such as air conditioning and electric stoves. In
addition, approximately half of the lower powered items, such as lights
and
the refrigerator, are powered by each of the two legs to the center
tap--which is approximately ground potential.

Ahhh! But where does the 240 come from?
Does it not come from two of the three legs of a Y or Delta?
These are square root and cube root functions.
If they were 180 out of phase, it would cancel.

They add, rather than cancel, and do come from two legs of a delta.

Remember that the power is transmitted down the street at a much higher
voltage, and the drop to each small cluster of residences is the output of a
transformer with its center-tap referenced to ground potential. The ground
wire, in my part of the country, also serves as the messenger cable
(physical structure) and is the bare wire that you see when you look up at a
typical residential service drop.

Peter

On Wed, 22 Nov 2006 20:11:12 GMT, john smith wrote:

In article ,
"Peter Dohm" wrote:


180 degree out-of-phase" voltage level.

Are you certain you don't mean 120- or 240-degrees out of phase?

How does one get two lines 180-degrees out of phase?

240V single phase, commonly supplied to single family dwellings, has a
center tap and two hot leads which are 180 degrees out of phase to supply
higher powered items such as air conditioning and electric stoves. In
addition, approximately half of the lower powered items, such as lights and
the refrigerator, are powered by each of the two legs to the center
tap--which is approximately ground potential.

Ahhh! But where does the 240 come from?
Does it not come from two of the three legs of a Y or Delta?
These are square root and cube root functions.
If they were 180 out of phase, it would cancel.

In north american residential and in most cases rural electricity, the
220 is NOT derived from a delta or wye connected three phase, but from
a simple center tapped power transformer on a single phase line (or
one leg of a three phase line - not 2). 208 is derived from 3 phase,
and is only found in SOME buildings where 3 phase is required for
other purposes, such as multi-unit residential buildings with 3 phase
elevators, or commercial/industrial applications.
Even in many of these situations, a center tapped transformer (single
phase) is used to provide the 120/240 single phase domestic power.(at
least in Ontario Canada)

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