Two phases or not?
David Nebenzahl
newsgroup (alt.home.repair) about phases in electrical power.
Over there, someone posted a question about GFCI breakers that morphed
into a discussion of multiphase electrical power. A disagreement arose
thereafter about whether a center-tapped transformer actually delivers
two separate phases of electricity or not. I'd like to get opinions
here, since at least some folks here have engineering backgrounds: over
there (a.h.r.), not so much. People there tend to be more electrician
types, rather than EEs and such.
The discussion started with a mention of 2-phase power. Turns out that
in the world of electrical power, this has a specific meaning. It refers
to a now-obsolete system of generating power in 2 phases that were 90°
apart, and was used at Niagara Falls:
http://www.3phasepower.org/2phasesystems.htm
And of course there's 3-phase power, widely used today.
The problem is this: several people, myself included, contend that the
two "legs" of power produced by a center-tapped transformer do, in fact,
constitute two separate phases of power, 180° apart. (This is how
household power is delivered in North America, with a step-down xfmr at
the power pole delivering 240 volts in the form of 120-0-120.)
Now it's true that in the electrical industry, this is called
"split-phase" power, and if you tried to tell the guy behind the counter
at the electrical supply house that it's 2-phase, he'd look at you funny.
However, I (and others) say that this is, in fact, true 2-phase power,
even if it's not called that. It just happens to be trivially easy to
generate it from a single phase, as it only involves inversion. (Unlike
3-phase, which requires rotary converters or electronic devices to
generate from single-phase power.)
Take, for example, any push-pull amplifier with a phase inverter or
phase splitter in front of it: it generates two separate phases out of a
single phase.
So, what do y'all say?
--
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.
Phil Allison
"David Nebenzahl"
** It's clearly two phase power, no doubt about that.
There are two AC waves that differ only in phase and if both "phases" are
loaded equally, the neutral current is zero.
So it is completely analogous to three phase power.
The 90 degree system is just an obsolete odd ball only a moronic pedant
would even mention.
.... Phil
Jamie
get screwed up at times.
You have a CT (center Tap) this gives you 2 phases, using the
CT as the common, which of course are 180 degrees apart. How ever,
if you need 230 volts, you would need to use the 2 outer legs which
will only give you a single phase for that circuit. Hence, only
one winding over all. CT means nothing here.
To qualify for a phase, it must has a common or an opposing leg.
Lets look at a floating Delta 3 phase system, even though it has
no common to qualify it as 3 circuits 120 degree's out of phase, it
does have 3 separate windings, each 120 degree's out and can supply
a circuit on each winding if it wished.
Looking at a STAR (WYE), one end of each phase (winding) is connected
to a common point.. This common point does not need to be used but is in
some cases.
The point is, there are 3 individual windings that are out of phase
with each other. Makes it 3 phase...
In the case of residential, the CT will give you 2 phases of 180
degree's when you only need 115 volt circuits how ever, because the
transformer here is really only a single winding with a CT, when you
need full voltage for 230 appliances, that circuit ends up being
a single phase.. How ever, most appliances like that also have the
CT/Neutrual so it can use half of that to operate the control electronics.
Some people call it split phase, only because you are taking a single
phase and splitting it in the middle. But that does give you a 2 phase
source if you to use the CT as the common for both.. It would be the
same as 2 transformers with their secondaries joined on one side only to
form a CT.
Remember "Split Phase" only means a single winding with a CT it,
hence, you have split the phase in half!
Now here's a tricky one.. Just think of the 3 phase system with a CT
in each winding. Now we're talking ! :)
Jamie
Brenda Ann
"Jamie" wrote in message news:xus_o.84$9r...@newsfe19.iad...
Remember "Split Phase" only means a single winding with a CT it,
hence, you have split the phase in half!
Now here's a tricky one.. Just think of the 3 phase system with a CT
in each winding. Now we're talking ! :)
Jamie
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Never seen one like that, but have seen a center tap on one winding to add
240/120 split phase to 3 phase 240 Delta. Tap I've seen on Wye (star)
garners 120 from any phase to neutral and 208 from phase to phase. (all this
if my memory isn't completely FUBAR)
nesesu
wrote:
> "Jamie" wrote in messagenews:xus_o.84$9r...@newsfe19.iad...
>
> Remember "Split Phase" only means a single winding with a CT it,
> hence, you have split the phase in half!
>
> Now here's a tricky one.. Just think of the 3 phase system with a CT
> in each winding. Now we're talking ! :)
>
> Jamie
>
> --------------------------------------------------------------------------------
> Never seen one like that, but have seen a center tap on one winding to add
> 240/120 split phase to 3 phase 240 Delta. Tap I've seen on Wye (star)
> garners 120 from any phase to neutral and 208 from phase to phase. (all this
> if my memory isn't completely FUBAR)
The system you mention was somewhat common in the '30s for large
apartments/ medium hotels/ small commercial and the like where they
would have a centre tapped 115/230V say 50kVA transformer across one
phase and a pair of say 5kVA 230V transformers across the other two
phases of a 3 phase supply [typically 2300V back then] and connected
in delta with the 50kVA. The lighting and appliances were powered off
the 50kVA while the elevators and laundry motors were powered from the
3 phase. It seems that most of those systems were replaced with 3
phase 4 wire wye or one large single phase transformer and a three
transformer delta system when the primary distribution was upgraded or
when the customer load increased after WWII.
I still see the occasional 3 phase open delta [two transformers] where
the 3 phase load is fairly light such as rural irrigation pumps that
are a bit too large HP for single phase.
Neil S.
William Sommerwerck
you would clearly have two phases. (I think.)
But the center tap gives them a common neutral. So are they still separate
phases? I'm inclined to say yes, because in a conventional three-phase
system, loads can be attached to individual phases, or across two phases for
a higher voltage. And these are considered multi-phase systems.
PeterD
<nob...@but.us.chickens> wrote:
>The discussion started with a mention of 2-phase power. Turns out that
>in the world of electrical power, this has a specific meaning. It refers
>to a now-obsolete system of generating power in 2 phases that were 90°
>apart, and was used at Niagara Falls:
>
>http://www.3phasepower.org/2phasesystems.htm
>
>And of course there's 3-phase power, widely used today.
>
>The problem is this: several people, myself included, contend that the
>two "legs" of power produced by a center-tapped transformer do, in fact,
>constitute two separate phases of power, 180° apart. (This is how
>household power is delivered in North America, with a step-down xfmr at
>the power pole delivering 240 volts in the form of 120-0-120.)
>
Well, if you want to be correct, the house power is split phase, and
not two phase. I suppose there is an arguement that it is two phase,
but say that to a power engineer and you'll get the old raised
eyebrows response!
Jeffrey Angus
> Well, if you want to be correct, the house power is split phase, and
> not two phase. I suppose there is an arguement that it is two phase,
> but say that to a power engineer and you'll get the old raised
> eyebrows response!
Ding! We have a winner.
Thank you peter.
Jeff
Fred McKenzie
"William Sommerwerck" <grizzle...@comcast.net> wrote:
> If there were two electrically isolated windings, with opposite polarity,
> you would clearly have two phases. (I think.)
Reminds me of the story of two carpenters. One says, "Half of my nails
have the head on the wrong end." His partner responds, "You dummy,
those are for the other side of the house!"
PeterD
wrote:
And the other carpenters doing the other side of the house: "Damn, I
just cut this board too short." His partner replies, "Simple, just
turn it around and cut somemore off the other end..."
David Nebenzahl
Welllll ... that's pretty much what I wrote. So I take it you agree with
me that it is, in fact, 2-phase power, correct?
Jeffrey Angus
> On 1/22/2011 5:27 AM PeterD spake thus:
>
>> On Fri, 21 Jan 2011 18:09:26 -0800, David Nebenzahl
>> <nob...@but.us.chickens> wrote:
>>
>>> The discussion started with a mention of 2-phase power. Turns out
>>> that in the world of electrical power, this has a specific meaning.
>>> It refers to a now-obsolete system of generating power in 2 phases
>>> that were 90° apart, and was used at Niagara Falls:
>>>
>>> http://www.3phasepower.org/2phasesystems.htm
>>>
>>> And of course there's 3-phase power, widely used today.
>>>
>>> The problem is this: several people, myself included, contend that
>>> the two "legs" of power produced by a center-tapped transformer do,
>>> in fact, constitute two separate phases of power, 180° apart. (This
>>> is how household power is delivered in North America, with a
>>> step-down xfmr at the power pole delivering 240 volts in the form
>>> of 120-0-120.)
>>
>> Well, if you want to be correct, the house power is split phase, and
>> not two phase. I suppose there is an arguement that it is two phase,
>> but say that to a power engineer and you'll get the old raised
>> eyebrows response!
>
> Welllll ... that's pretty much what I wrote. So I take it you agree with
> me that it is, in fact, 2-phase power, correct?
>
In a word, no.
Power distribution being what it is, the 240/120 transformer on the
pole is sourced with _ONE_ phase of the 3-phase feed for the area.
That there is a center tap allowing for 120/120 or 240 loads is
immaterial. It's STILL single phase.
Jeff
Phil Allison
"Jeffrey Angus"
>
>>
>> Welllll ... that's pretty much what I wrote. So I take it you agree with
>> me that it is, in fact, 2-phase power, correct?
>>
>
> In a word, no.
>
> Power distribution being what it is, the 240/120 transformer on the
> pole is sourced with _ONE_ phase of the 3-phase feed for the area.
** Totally irrelevant how the 2-phase is derived.
> That there is a center tap allowing for 120/120 or 240 loads is
> immaterial. It's STILL single phase.
** Pedantic nonsense.
There are two AC waves that differ only in phase and if both "phases" are
loaded equally, the neutral current is zero.
So it is completely analogous to 3-phase power.
David Nebenzahl
I have to say I totally agree with Phil here. Especially the reference
to "true" 2-phase power brought up in this argument (the one over on
a.h.r), meaning that totally antiquated and obsolete system.
Those with which I disagree seem to think that just because the two
phases aren't somehow manufactured separately, by two different windings
of a generator or some such, that the center-tapped xfmr can't possibly
supply two separate phases, when it so clearly does just that.
David Nebenzahl
> Power distribution being what it is, the 240/120 transformer on the
> pole is sourced with _ONE_ phase of the 3-phase feed for the area.
> That there is a center tap allowing for 120/120 or 240 loads is
> immaterial. It's STILL single phase.
Keep in mind the premise of my original question. Remember I pointed out
that 120-0-120 current supplied by a center-tapped transformer is *not*
called "2-phase" by those in the electrical power industry, but that it
is, in fact, 2-phase power. Do you disagree that there are actually two
separate phases of power present at the secondary of the transformer?
Regardless of what they call it ...
Jamie
having a CT in a winding gives you 2 phases, 180 apart..
Calling it split phase is just a method of doing it.
Lets look at it this way..
Take a control xfomer..
If I was to wire the secondary as
X1, X2+X3, X4;
X2 and X3 being the CT, I now have a source that has 2 secondaries
(2 windings) that can give me 180 degree shift via the CT. This gives
me 2 phases..Why? because they are not in phase with each other.. It
does not matter if they are only 1 degree off from each other.. They
would be two difference phases, because we are using the CT as the
common point. Same as, if you were to use the STAR Center of a WYE
transformer as the common point, this would give you 3 phases which
we all know are 120 degrees different from each one. The analogy isn't
any different if you had the pole pig which is just a single winding
with a CT in it on the secondary side for your common. Other wise known
as a split phase because can treat that as a single phase to get the
full voltage or split phase to get half voltage with 180 shifts.(2 phases)
Now, take that same xformer I have above there and....
X2, X1+X3, X4;
What do you get? You get two different power points sharing a CT but
in phase with each other. And yes, I've seen this done before to avoid
over voltage through grounds if the neutral was ever lifted for some
reason. This basically is only one phase and does not allow you to
use them for double voltage. In fact, you'll get no voltage between X2
and X4.
Oh well.
Jamie
Jeffrey Angus
> On 1/22/2011 4:45 PM Jeffrey Angus spake thus:
>
>> Power distribution being what it is, the 240/120 transformer on the
>> pole is sourced with _ONE_ phase of the 3-phase feed for the area.
>> That there is a center tap allowing for 120/120 or 240 loads is
>> immaterial. It's STILL single phase.
>
> Keep in mind the premise of my original question. Remember I pointed out
> that 120-0-120 current supplied by a center-tapped transformer is *not*
> called "2-phase" by those in the electrical power industry, but that it
> is, in fact, 2-phase power. Do you disagree that there are actually two
> separate phases of power present at the secondary of the transformer?
>
> Regardless of what they call it ...
>
>
Nope, single phase.
The definition of "more than one" phase is a difference
of something other than 0 or 180 degrees.
With either 2-Phase (the old 90 degree system) or 3-phase
(current 120 degree system) the phases can NOT be generated
with a simple transformer. They are generated by multiple
alternators mounted on a common shaft.
With a single transformer, and a center tap, you have two
voltages, in phase, that add together.
It's single phase.
Jeff
Jamie
Oh, so now that we have a CT as a neutral (common), how do you explain
the two different phase angles we now have ?
Last time I went to school, phase count was the number of
phase angles you have that are unique in degrees.
does not matter how you derived it..
If I plug in an inverter that operates from a single phase circuit
and it generates 3 phases that are 120 degree's apart, does that mean
it much be single phase because it started from a single phase source?
Jamie
David Nebenzahl
> If I plug in an inverter that operates from a single phase circuit
> and it generates 3 phases that are 120 degree's apart, does that mean
> it much be single phase because it started from a single phase source?
Excellent question. I await answers.
So far, we have two objections to a center-tapped transformer giving two
phases, both very doubtful:
1. Not two phase because the "source" (i.e., the other side of the xfmr)
is single phase.
2. Not two phase because two phases that are 180� are not actually two
phases (?!?!?!).
Phil Allison
"Jeffrey Angus"
>
> Nope, single phase.
>
> The definition of "more than one" phase is a difference
> of something other than 0 or 180 degrees.
** Who's " definition " is that ????
I wonder ........
..... Phil
Bob AZ
> And of course there's 3-phase power, widely used today.
>
> The problem is this: several people, myself included, contend that the
> two "legs" of power produced by a center-tapped transformer do, in fact,
> constitute two separate phases of power, 180° apart. (This is how
> household power is delivered in North America, with a step-down xfmr at
> the power pole delivering 240 volts in the form of 120-0-120.)
>
David et al
A specific that many are not aware of and are left wondering when
discussed is the following.
The transformer that feeds your home and many small businesses has a
single phase impressed across the primary winding. Usually called a HV
winding. No big deal for this discussion. The "secondary winding" is
actually two identical windings. Sometimes called tertiary windings.
But this term usually leaves most on the dark. Not a commonly used
term since we don't usually get into the actual electrical and/or
mechanical construction of transformers, let alone the ones feeding
our homes. To most they are simply an unknown on the pole in the alley
or in a pedestal box in the front yard of residential houses.
Back to the actual transformer. A primary winding and two identical
secondary windings. The seondary windings are wound identically within
and about the primary winding. Well insulated of course. The primary
winding impresses each winding identically, in this case, 120 volts.
So the operation of the secondary windings are identical.
The secondary windings are connected in an addtive fashion to give 240
volts across the ends of the connected windings. Their common
terminal, internally connected, is sometimes thought of as a "center"
tap. But the windings are not actually centertapped. They are only
connected in a additive fashion to give the desired 240 volts. 120
volts is of course is simply a connection to a hot lead and the
common terminal. When both windings are utilized we end up with two
"hot" leads which are used for the 120 volt loads. The same additive
principle could be used to give perhaps 360 or 480 volts.
But in no case, with the information presented here, is there any
method or device utilized to give any additional phases. One or two or
more. The hot legs are simply the same phase, transformed as needed,
added within the transformer, with the resultant two hot legs, 180
degrees out of phase with each other. Were the windings connected "in
phase" the available voltage would be 50% and the power, amps,
available doubled.
Three phase distribution starts with a generator with 3 sets of
windings that is distributed as three phase and utuilzed as needed.
Residential as this discussion continues, and large users with many
motor (inductive) loadings commonly found in motors 5 or more HP. The
5 HP figure is an industry norm that takes advantage of the inherent
advantages of 3 phase. Mainly distribution costs and three phase
motors.
Disclaimer: Transformers, power distribution, are not my usual area of
expertise. This would be several different lifelong careers followed
by others. I simply deal with it on an almost daily basis and have for
over 50 years.
Enough for a long day.
Bob AZ
Phil Allison
"Bob AZ"
( snip tedious drivel)
But in no case, with the information presented here, is there any
method or device utilized to give any additional phases. One or two or
more. The hot legs are simply the same phase, transformed as needed,
added within the transformer, with the resultant two hot legs, 180
degrees out of phase with each other.
** A really beautiful example of "double think" if I ever saw one.
Three phase distribution starts with a generator with 3 sets of
windings that is distributed as three phase and utuilzed as needed.
** And if it had only 2 windings instead of 3 ??
Two AC waves would be produced simultaneously, remaining always 180 degrees
apart in phase and be completely * indistinguishable * from any other means
of creating the same situation.
..... Phil
Jamie
Big JOKE!
You fail.
Jeffrey Angus
> Jeffrey Angus wrote:
>> It's single phase.
>>
>> Jeff
> Big JOKE!
>
> You fail.
I bow to your superior logic and wit.
Jeff
Mark Cross
> A disagreement arose
> thereafter about whether a center-tapped transformer actually delivers
> two separate phases of electricity or not.
> So, what do y'all say?
Formally, yes, there exist two phases set apart 180º. But formally also that
is never called a "two-phase system".
Reasons:
1.- In polyphase system there is an usual understanding that phases are
different when you can not get the other phase by simple means other than
using transformers (or transformer arrays). In a 3 Phase system, there is no
way to get a phase 120º away by adding, subtracting or switching cable ends
of one phase. In a true two phase system, be it a three wire part of a 3
phase system or the Niagara example, there is no way to get the other phase
(120º or 90º) by playing with the connections. In a "split phase" system,
the 180º phase is equal (in a balanced system) to the other one by just
exchanging the "hot" and "ground" wires.
2.- The phase supplying the power to the "split-phase" winding in the
secondary of home transformers is only ONE, there is no way to get more than
ONE phase out, even if formally the secondary winding could be measured
reversing the leads and appear as the negative value (hence the 180º figure)
Those two windings of the "split-phase system" are connected in such a way
as to provide a total voltage of 240V but could have been connected in
parallel to provide the double of current in one phase at 120V. Such
parallel connection would produce a "short" and high currents if in fact the
two windings were being driven by two distinct phases no matter what games
you play with the wire ends.
So, that's why any power engineer will raise an eyebrow if you address such
system with the clearly incorrect term of "two-phase system".
--
Mark Cross
If Linux doesn't have the solution, you have the wrong problem.
Michael A. Terrell
Look at his website before you concede.
http://webpages.charter.net/jamie_5/
--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.
Michael A. Terrell
If the generator had two windings, they would be 90 degrees out of
phase. It makes zero sense to have them at 180 degrees, since the
windings would have to share the slots, reducing the availible current
by half.
Wild_Bill
that most of us use. For single phase motors, a 120VAC motor is a
single-phase motor, just as a 240VAC motor is referred to as a single-phase
motor, not a 2-phase motor because it's using 2 hot lines.
This issue is one that just gets argued endlessly by amateurs and intellects
to no end.. essentially a waste of useful time on an issue that's widely
misunderstood for all the wrong reasons.
Pick the issue apart just for sport, if you like, but the majority of
domestic power supplies are single-phase.. period.
Look anywhere you can for a New 2-phase motor.
The only individuals that would be describing a new motor as a 2-phase motor
will be some misguided trainee or someone taking advantage of your stupidity
of asking for one.
--
Cheers,
WB
.............
"Mark Cross" <markcros...@gmx.com> wrote in message
news:2156246.b...@rnqqfki.new.org.invalid...
Phil Allison
"Wild_Bill"
>
> These comments are logical and correct representations of the power system
> that most of us use. For single phase motors, a 120VAC motor is a
> single-phase motor, just as a 240VAC motor is referred to as a
> single-phase motor, not a 2-phase motor because it's using 2 hot lines.
** Massive straw man fallacy.
Why am I not surprised it comes from a fucking TOP POSTER !!
.... Phil
David Nebenzahl
> These comments are logical and correct representations of the power system
> that most of us use. For single phase motors, a 120VAC motor is a
> single-phase motor, just as a 240VAC motor is referred to as a single-phase
> motor, not a 2-phase motor because it's using 2 hot lines.
>
> This issue is one that just gets argued endlessly by amateurs and intellects
> to no end.. essentially a waste of useful time on an issue that's widely
> misunderstood for all the wrong reasons.
I disagree entirely. Yes, in this case it's a semantic debate--what I
contend is actually 2-phase power (120-0-120 derived from a
center-tapped transformer) is not *called* that by the electric power
industry. It is, nonetheless, truly two phase power.
I think it's important because the idea of phases in electrical power is
an important one, even to a simpleton like the average electrician,
never mind the EE.
Example: if you're going to wire an Edison circuit (where two hots from
different phases, meaning different sides of the distribution panel, are
wired with a common neutral), you ought to understand electrical phases,
especially the consequences of two phases 180° apart. After all, that's
how the currents from the two sides cancel each other. Failure to grasp
such principles can, and do, lead to real-world consequences like
building fires.
> Pick the issue apart just for sport, if you like, but the majority of
> domestic power supplies are single-phase.. period.
> Look anywhere you can for a New 2-phase motor.
Who said anything about a 2-phase motor? Nobody, so far as I can tell.
I'm saying that the ENTIRE DOMESTIC POWER SUPPLY FROM THE SECONDARY OF
THE POWER COMPANY'S TRANFORMER is 2-phase. Once you plug in a 120 volt
anything, or even many 240 volt anythings, you're only using one phase.
Sheesh.
> The only individuals that would be describing a new motor as a 2-phase motor
> will be some misguided trainee or someone taking advantage of your stupidity
> of asking for one.
Again, where did this straw man come from?
Please notice that because of your non-standard top posting, any
previous replies have been cut off. Please do what 99% of others do here
and bottom post.
Jamie
> On 1/23/2011 4:44 PM Wild_Bill spake thus:
>
>> These comments are logical and correct representations of the power
>> system that most of us use. For single phase motors, a 120VAC motor is
>> a single-phase motor, just as a 240VAC motor is referred to as a
>> single-phase motor, not a 2-phase motor because it's using 2 hot lines.
>>
>> This issue is one that just gets argued endlessly by amateurs and
>> intellects to no end.. essentially a waste of useful time on an issue
>> that's widely misunderstood for all the wrong reasons.
>
>
> I disagree entirely. Yes, in this case it's a semantic debate--what I
> contend is actually 2-phase power (120-0-120 derived from a
> center-tapped transformer) is not *called* that by the electric power
> industry. It is, nonetheless, truly two phase power.
>
> I think it's important because the idea of phases in electrical power is
> an important one, even to a simpleton like the average electrician,
> never mind the EE.
>
> Example: if you're going to wire an Edison circuit (where two hots from
> different phases, meaning different sides of the distribution panel, are
> wired with a common neutral), you ought to understand electrical phases,
> especially the consequences of two phases 180° apart. After all, that's
> how the currents from the two sides cancel each other. Failure to grasp
> such principles can, and do, lead to real-world consequences like
> building fires.
>
>> Pick the issue apart just for sport, if you like, but the majority of
>> domestic power supplies are single-phase.. period.
>
>
>> Look anywhere you can for a New 2-phase motor.
>
>
> Who said anything about a 2-phase motor? Nobody, so far as I can tell.
>
> I'm saying that the ENTIRE DOMESTIC POWER SUPPLY FROM THE SECONDARY OF
> THE POWER COMPANY'S TRANFORMER is 2-phase. Once you plug in a 120 volt
> anything, or even many 240 volt anythings, you're only using one phase.
> Sheesh.
>
>> The only individuals that would be describing a new motor as a 2-phase
>> motor will be some misguided trainee or someone taking advantage of
>> your stupidity of asking for one.
>
>
> Again, where did this straw man come from?
>
> Please notice that because of your non-standard top posting, any
> previous replies have been cut off. Please do what 99% of others do here
> and bottom post.
>
>
Don't waste your breath. it's not worth the effort.
Knowing that you understand it should be enough..
And by the way, I was looking at a 3 wire motor today, 2 phases of 180
apart with CT to operate it (3 wire motor). It was attached to a gear
box and only ran one direction, but you could use it as a stepper
(servo) or full out run. Most likely some custom motor for an application.
Jamie
Wild_Bill
capacitance included, with a low value of 25uF or less?
I think you may have been looking at a PSC permanent split capacitor motor..
although I haven't seen any rated at 180V. Most 3-wire motors are PSC types.
BTW, PSC motors aren't defined or referred to as 2-phase motors.
They may be specified for some particular rating as single-direction motors,
but they are reversible, in fact, fast stopping/reversing is one of the
features of PSC motors.
The gearheads, and especially the right-angle gearheads with encoders
attached are very versatile.
--
Cheers,
WB
.............
"Jamie" <jamie_ka1lpa_not_v...@charter.net> wrote in message
news:de5%o.16039$TZ4....@newsfe20.iad...
JW
<mike.t...@earthlink.net> wrote in Message id:
<MaWdnaQtrvvZHaHQ...@earthlink.com>:
>
>Jeffrey Angus wrote:
>>
>> On 1/23/2011 9:05 AM, Jamie wrote:
>> > Jeffrey Angus wrote:
>> >> It's single phase.
>> >>
>> >> Jeff
>> > Big JOKE!
>> >
>> > You fail.
>>
>> I bow to your superior logic and wit.
>
>
> Look at his website before you concede.
>
>http://webpages.charter.net/jamie_5/
Ack! I almost went blind after seeing that pic on the right.
Wild_Bill
if the motors are not for 3-phase.
Just to be more specific (although 3-phase wasn't being included in the
topic).
--
Cheers,
WB
.............
"Wild_Bill" <wb_wi...@XSPAMyahoo.com> wrote in message
news:j59%o.612113$De6....@en-nntp-01.dc1.easynews.com...
Michael A. Terrell
Now you know not to listen to him.
Michael Kennedy
"David Nebenzahl" <nob...@but.us.chickens> wrote in message
news:4d3a3c1e$0$31597$8226...@news.adtechcomputers.com...
> I'm posting this to try to settle an argument going on in another
> newsgroup (alt.home.repair) about phases in electrical power.
<SNIP>
And you have started another arguement here. haha..
Honestly this is a question that I have always had, and can't understand why
it isnt called 2 phase. Unless there is something to the picture I am
unaware of.
This qustion will enevetably be debated to the end of time. It is kind of
like discussing poloitcs or religion..
David Nebenzahl
Well, it really shouldn't be like that. I mean, look, we're discussing a
well-known, measurable phenomenon. The output of the center-tapped
transformer can be demonstrated to supply two separate and distinct
phases. Hell, hook up two 'scopes and see what they show.
It's just that the 'lectric-heads--the lunks who install distribution
panels and such--won't let us *call* it "2-phase" for several dubious
reasons. Doesn't change the fact that it IS two-phase power. That's what
I'm getting at. I'm not trying to force anyone to change their
terminology or give up their superstitious beliefs; I know that that's
futile.
Michael Kennedy
"David Nebenzahl" <nob...@but.us.chickens> wrote in message
> On 1/24/2011 7:40 PM Michael Kennedy spake thus:
>
>> "David Nebenzahl" <nob...@but.us.chickens> wrote in message
>> news:4d3a3c1e$0$31597$8226...@news.adtechcomputers.com...
>>
>>> I'm posting this to try to settle an argument going on in another
>>> newsgroup (alt.home.repair) about phases in electrical power.
>>
>> <SNIP> And you have started another arguement here. haha..
>>
>> Honestly this is a question that I have always had, and can't understand
>> why it isnt called 2 phase. Unless there is something to the picture I am
>> unaware of.
>>
>> This qustion will enevetably be debated to the end of time. It is kind of
>> like discussing poloitcs or religion..
>
> Well, it really shouldn't be like that. I mean, look, we're discussing a
> well-known, measurable phenomenon. The output of the center-tapped
> transformer can be demonstrated to supply two separate and distinct
> phases. Hell, hook up two 'scopes and see what they show.
>
> It's just that the 'lectric-heads--the lunks who install distribution
> panels and such--won't let us *call* it "2-phase" for several dubious
> reasons. Doesn't change the fact that it IS two-phase power. That's what
> I'm getting at. I'm not trying to force anyone to change their terminology
> or give up their superstitious beliefs; I know that that's futile.
>
>
Unfortunately. Maybe we should more generic terminology to describe this.
There is a difference in the phase of the two legs off of a center tapped
transformer. This can not be argued. Anyone who argues so can go hook up a
couple scopes for themselves as you suggested.
Maybe the confusion exsists because of the nature of two seperate phase
(split phase) power vs 3. Correct me if I am wrong, but any device requiring
240V could be powered by 2 legs of a center tapped 7200V==>120V N 120V
transformer or could be powered by a 7200V==>240V transformer with the same
results.
That said Im sure someone will tell me why my theory of why this is a
confusion is wrong..
- Mike
Michael Kennedy
"Michael Kennedy" <mike@com> wrote in message
news:bISdncmHWep_5qPQ...@giganews.com...
Hmm.. I must have not drank my coffee yet when I wrote this.. 3 phase would
operate the same way therefore making this all bunk.
David
> describe this. There is a difference in the phase of the two
> legs off of a center tapped transformer. This can not be
> argued. Anyone who argues so can go hook up a couple scopes for
> themselves as you suggested.
>
> Maybe the confusion exsists because of the nature of two
> seperate phase (split phase) power vs 3. Correct me if I am
> wrong, but any device requiring 240V could be powered by 2 legs
> of a center tapped 7200V==>120V N 120V transformer or could be
> powered by a 7200V==>240V transformer with the same results.
>
> That said Im sure someone will tell me why my theory of why
> this is a confusion is wrong..
>
> - Mike
|Hmm.. I must have not drank my coffee yet when I wrote this.. 3
phase would
|operate the same way therefore making this all bunk.
Actually three phase service from the power company with the
phases 120 degrees apart, would work differently. In a 'Y'
connection if the voltage between the phases were X volts, the
voltage from one phase to neutral would be x/sqrt(3) rather than
x/2 as is the case with a center tapped transformer.
David
Wild_Bill
single-phase items 2-phase instead, is free to find humor in it, or suspect
that you're uninformed, or lesser of you (without giving you any
indications).
Kinda like referring to an item with a perfectly practical/widely familar
name "a thingy", or a (something) thingy.
Superstitious would be applicable in the early years of the last century
when folks actually believed that distributed electricity was "fire on a
wire".
It was a mysterious power to be feared by many folks in backwoods/mountain
places in Appalachia for a significant portion of last century, and that
same term can be heard in documentary films of that area of the country.
Think what you like, but if you present yourself as being wiser or more
reasonable wrt the subject, it's essentially just trolling.. and since you
study proper usenet protocol, you know that's the equivalent to numerous
simultaneously performed deadly sins.
It's likely no one gives a FRA what you prefer to call single-phase,
however, many usenet folks will likely continue to attempt to correct you at
your use of the term 2-phase, primarily because it's not applicable to the
subject matter.. and just because 2-phase power is essentially non-existent.
As I suggested in my first reply in this thread.. essentially debated to
hell'n back, and still, there are still those defending the use of the term
2-phase.
--
Cheers,
WB
.............
"David Nebenzahl" <nob...@but.us.chickens> wrote in message
news:4d3e4a7b$0$21367$8226...@news.adtechcomputers.com...
Wild_Bill
consumer electronic equipment and additional training and experience in
industrial site experience (both electrical and electronic circuits), I have
never seen descriptions or designations stated as 2-phase, for any type of
transformer.
Or: Hey bub, you gotta single-phase-in, 2-phase-out transformer?
But I have seen and used transformers with multiple taps, on both pri and
sec sides.
The number of taps on either side of a single-phase transformer don't change
the output(s) to 2-phase, regardless of how many there are (pri or sec
side).
Monophase sounds odd, like it's not related to electricity.
How about uniphase? Yep, found an example (and diphase) used in a book c
1905.
Electricity In Every-day Life Edwin J. Houston PhD. You know that's gonna be
interesting just because it was authored by a PhD.
--
Cheers,
WB
.............
"Michael Kennedy" <mi...@nospam.com> wrote in message
news:t5CdnYPUlJL5bqPQ...@giganews.com...
Michael Kennedy
>
> "David Nebenzahl" <nob...@but.us.chickens> wrote in message
> news:4d3e4a7b$0$21367$8226...@news.adtechcomputers.com...
>>
>> Well, it really shouldn't be like that. I mean, look, we're discussing a
>> well-known, measurable phenomenon. The output of the center-tapped
>> transformer can be demonstrated to supply two separate and distinct
>> phases. Hell, hook up two 'scopes and see what they show.
>>
>> It's just that the 'lectric-heads--the lunks who install distribution
>> panels and such--won't let us *call* it "2-phase" for several dubious
>> reasons. Doesn't change the fact that it IS two-phase power. That's what
>> I'm getting at. I'm not trying to force anyone to change their
>> terminology or give up their superstitious beliefs; I know that that's
>> futile.
>>
>>
>
"Wild_Bill" <wb_wi...@XSPAMyahoo.com> wrote in message
news:F1E%o.415936$zE6.3...@en-nntp-03.dc1.easynews.com...
Oh I completely agree that the terminology is split phase and or center
tapped.. Just after reading all of this I am trying to rationalize why there
is so much debate.. I mean they are different phases 180deg apart. That is
measurable. I just cant understand why some refuse the fact that they are 2
different phases, i.e. "split-phase" as the name implies. This fits the
definiton of a different phase of power. Im not trying to change any
terminology in the process here.
Mike
Bob AZ
> Oh I completely agree that the terminology is split phase and or center
> tapped.. Just after reading all of this I am trying to rationalize why there
> is so much debate.. I mean they are different phases 180deg apart. That is
> measurable. I just cant understand why some refuse the fact that they are 2
> different phases, i.e. "split-phase" as the name implies. This fits the
> definiton of a different phase of power. Im not trying to change any
> terminology in the process here.
>
MIke et al
The problem seems to be that after all this dialogue, that so many of
the responders simply don't stick to the basic premise that different
phases by definition have timing differences. Simply reversing the way
of using a phase does not make it a different phase. The timing stays
the same.
If one uses an oscillioscope to view the phase it can be readily
reversed to appear as another when it is not. We connect windings in
the power transformer that feeds our residence to get the desired
result, 120 or 240 and connect the common point to accomplish another
desired result. Safety. Also the ungrounded winding would be floating
about a possible potential of several thousand volts and be a real
hazard should there be a problem in any of the many devises connected
to the secondary. Including the two seconday windings. And yes there
are two identical secondary windings. If there were not our electric
bills would at least double. Lots of folks would die and lots of
devises would be hazardous to all. Thus the emphasis on proper
grounding in the interests of public welfare. But this is another
subject.
Bob AZ
Phil Allison
"Bob AZ"
The problem seems to be that after all this dialogue, that so many of
the responders simply don't stick to the basic premise that different
phases by definition have timing differences.
** More total nonsenese.
Sine waves of the exact same frequency and amplitude can ONLY differ only in
phase.
A 180 degree phase difference is as good as any other.
.... Phil
Fred McKenzie
"Phil Allison" <phi...@tpg.com.au> wrote:
> Sine waves of the exact same frequency and amplitude can ONLY differ only in
> phase.
>
> A 180 degree phase difference is as good as any other.
Phil-
I have a flashlight powered by a two-phase system - two D cells. It
certainly fits your criteria. Its power system can also be considered
AC, since DC is just AC with frequency equal to zero.
Facts are no deterrent to a persistent troll!
Fred
Phil Allison
"Fred McKenzie"
>
> "Phil Allison"
>
>> Sine waves of the exact same frequency and amplitude can ONLY differ only
>> in
>> phase.
>>
>> A 180 degree phase difference is as good as any other.
>
>
** Nuh - that is DC, you pathetic troll.
> It certainly fits your criteria.
** Nuh - not one of them.
> Its power system can also be considered
> AC, since DC is just AC with frequency equal to zero.
** Just like white is the same as black with no lights on.
> Facts are no deterrent to a persistent troll!
** Just like reality is no deterrent to a lunatic.
Did someone leave the door open at the asylum today ??
..... Phil
Meat Plow
I'd make a comment here but it is against my new year's resolution.
--
Live Fast, Die Young and Leave a Pretty Corpse
Jamie
> Having a couple of decades experience in servicing/repair of commercial
> and consumer electronic equipment and additional training and experience
> in industrial site experience (both electrical and electronic circuits),
> I have never seen descriptions or designations stated as 2-phase, for
> any type of transformer.
>
> Or: Hey bub, you gotta single-phase-in, 2-phase-out transformer?
>
> But I have seen and used transformers with multiple taps, on both pri
> and sec sides.
> The number of taps on either side of a single-phase transformer don't
> change the output(s) to 2-phase, regardless of how many there are (pri
> or sec side).
> Monophase sounds odd, like it's not related to electricity.
> How about uniphase? Yep, found an example (and diphase) used in a book c
> 1905.
> Electricity In Every-day Life Edwin J. Houston PhD. You know that's
> gonna be interesting just because it was authored by a PhD.
>
> --
> Cheers,
> WB
> .............
You still lose:
You don't seem to know the difference between circuits and phase
angles..
Typical residential hack electrician..
I hope you don't ever decide to move in to electronics, you'd be in a
world of shit.
Jamie
What are you a fucking moron?
Phil Allison
"Jamie" = radio ham KA1LPA
>
> Fred McKenzie = radio ham K4DII
>
>>
>> I have a flashlight powered by a two-phase system - two D cells. It
>> certainly fits your criteria. Its power system can also be considered
>> AC, since DC is just AC with frequency equal to zero.
>>
>> Facts are no deterrent to a persistent troll!
>>
>> Fred
>
> What are you a fucking moron?
** Yep - Fred is another radio ham.
K4DII
Frederick M. McKenzie
2867 EPP Bivings Drive
Titusville, Fl 32796
..... Phil
Jamie
Look Phil, I may not agree with avery thing you say, but at least
I am supporting you in this debate...
And please don't use amateur operators as a signification of
stupidity..
You can't fix stupid, It has no classification.
And admit it Phil, you just wish you were a HAM! ;)
http://www.youtube.com/watch?v=5Z9136_Nhh4
Watch and Weep!
Jamie
Phil Allison
>
>Fred McKenzie = radio ham K4DII
>>>
>>>
>>>>I have a flashlight powered by a two-phase system - two D cells. It
>>>>certainly fits your criteria. Its power system can also be considered
>>>>AC, since DC is just AC with frequency equal to zero.
>>>>
>>>>Facts are no deterrent to a persistent troll!
>>>>
>>>>Fred
>>>
>>>What are you a fucking moron?
>>
>>
>> ** Yep - Fred is another radio ham.
>>
>> K4DII
>> Frederick M. McKenzie
>> 2867 EPP Bivings Drive
>> Titusville, Fl 32796
>>
>>
> I am supporting you in this debate...
** Yawnnnnnnn....
> And please don't use amateur operators as a signification of
> stupidity..
** Shame that so many radio hams on usenet prove themselves to be the
biggest trolls, trouble makers and blow hard bullshit artists ever.
Damn shame about that.
.... Phil
Jamie
why you have such animosity towards us, you speak from experience.
--... ...-- ...
Thou sayest, "Keep the brother hood together"!
Jamie
Phil Allison
"Jamie" = radio ham KA1LPA
> And please don't use amateur operators as a signification of
> stupidity..
** Shame that so many radio hams on usenet prove themselves to be the
biggest trolls, trouble makers and blow hard bullshit artists ever.
Especially YOU.
Jamie
Making assumptions like that about some one you know absolutely
nothing about, isn't very good character on your part. It just goes to
show how much of an ignoramus one could be, you for example.
Now, I understand your dilemma. I am forced to communication with
people of your type, every day. That does not mean I have to like it
how ever, it's a requirement I must adhere to.
Could it be these so called "Trouble Makers" as you call them are just
making you feel like you have too much competition ? I am sorry that
"we Amateur Operators don't kneel down and kiss your feet".
Jamie
P.S.
It's not nice trying to make yourself look better by devaluing others.
hint.
Michael Kennedy
>
>The problem seems to be that after all this dialogue, that so many of
>the responders simply don't stick to the basic premise that different
>phases by definition have timing differences. Simply reversing the way
>of using a phase does not make it a different phase. The timing stays
>the same.
>
Ok I get what your saying.. But do you understand what a phanse difference
is?? It is timing like you said..
Here is an explanation using audio waves. Maybe you can get what I am
saying.
Michael A. Terrell
Still trying to find people to join you?
Michael A. Terrell
Jamie wrote:
>
> Phil Allison wrote:
>
> > "Jamie" = radio ham KA1LPA
> >
> >>Fred McKenzie = radio ham K4DII
> >>
> >>
> >>>I have a flashlight powered by a two-phase system - two D cells. It
> >>>certainly fits your criteria. Its power system can also be considered
> >>>AC, since DC is just AC with frequency equal to zero.
> >>>
> >>>Facts are no deterrent to a persistent troll!
> >>>
> >>>Fred
> >>
> >>What are you a fucking moron?
> >
> >
> >
> > ** Yep - Fred is another radio ham.
> >
> > K4DII
> > Frederick M. McKenzie
> > 2867 EPP Bivings Drive
> > Titusville, Fl 32796
> >
> >
> >
> > ..... Phil
> >
> >
> >
> Look Phil, I may not agree with avery thing you say, but at least
> I am supporting you in this debate...
>
> And please don't use amateur operators as a signification of
> stupidity..
>
> You can't fix stupid, It has no classification.
Your parents could have prevented stupid.
Michael A. Terrell
By your definiton, a 'Push-Pull Output Transformer' is two phase.
David Nebenzahl
> Michael Kennedy wrote:
>
>>> MIke et al
>>>
>>> The problem seems to be that after all this dialogue, that so
>>> many of the responders simply don't stick to the basic premise
>>> that different phases by definition have timing differences.
>>> Simply reversing the way of using a phase does not make it a
>>> different phase. The timing stays the same.
>>
>> Ok I get what your saying.. But do you understand what a phanse difference
>> is?? It is timing like you said..
>>
>> Here is an explanation using audio waves. Maybe you can get what I am
>> saying.
>>
>> http://www.indiana.edu/~emusic/acoustics/phase.htm
>
> By your definiton, a 'Push-Pull Output Transformer' is two phase.
It IS two phase; that's the whole point. (At least on the primary side.)
I'd be interested in your explanation of how it isn't ...
(I think my example was a little more clear: look at a center-tapped
transformer used as the input to a push-pull stage and tell me there
aren't two phases there.)
Wild_Bill
for your 2-phase electrical service.
Ya Ignorant and apparently illiterate Cunt.. FOAD
--
Cheers,
WB
.............
"Jamie" <jamie_ka1lpa_not_v...@charter.net> wrote in message
news:FP30p.3113$Y8....@newsfe06.iad...
Michael A. Terrell
David Nebenzahl wrote:
>
> On 1/26/2011 7:45 PM Michael A. Terrell spake thus:
>
> > Michael Kennedy wrote:
> >
> >>> MIke et al
> >>>
> >>> The problem seems to be that after all this dialogue, that so
> >>> many of the responders simply don't stick to the basic premise
> >>> that different phases by definition have timing differences.
> >>> Simply reversing the way of using a phase does not make it a
> >>> different phase. The timing stays the same.
> >>
> >> Ok I get what your saying.. But do you understand what a phanse difference
> >> is?? It is timing like you said..
> >>
> >> Here is an explanation using audio waves. Maybe you can get what I am
> >> saying.
> >>
> >> http://www.indiana.edu/~emusic/acoustics/phase.htm
> >
> > By your definiton, a 'Push-Pull Output Transformer' is two phase.
>
> It IS two phase; that's the whole point. (At least on the primary side.)
Then a Williamson 'Ultra linear' output transformer is four phase?
<http://www.pmillett.com/file_downloads/stancor_ul_schematics.pdf>
See page 4 for a sample schmatic.
> I'd be interested in your explanation of how it isn't ...
>
> (I think my example was a little more clear: look at a center-tapped
> transformer used as the input to a push-pull stage and tell me there
> aren't two phases there.)
Then look at a Williamson 'Ultra linear' output transformer and tell
me there are four phases.
JW
My New Year's resolution was an easy one this year. Make no New Year's
resolutions ever again.
Michael A. Terrell
I made that one, over 30 years ago. :)
Wild_Bill
I assume some of the fuckwits in this thread would like to argue that the
outputs of a simple stereo amp (L+/gnd and R+/gnd), with a center channel
(L+ and R+) would be 3-phase.
Still.. it's not electrical power.
A Simple, Practical and Sensible approach to the difference between
electrical circuits, and electronic circuits is:
Electrical power circuits perform work (mechanical energy, heat etc).
Electronic circuits are for relaying information (data, sensing, control of
electrical devices, communications).
I'm done here.. another wasted minute of my remaining time isn't worthwhile
to me.
Have yer fun.
As I suggested in my first reply in this thread, this issue is simply food
(a drug?) for the dimwitted that have nothing better to do.
I can only imagine the good efforts that could have been attributed to real
issues worldwide.. with the time/effort that's been wasted by trillions of
minutes of worthless usenet replies and pissing contests.
--
Cheers,
WB
.............
"Michael Kennedy" <mike@com> wrote in message
news:_4idndEDCOOWdd3Q...@giganews.com...
Bob AZ
> Ok I get what your saying.. But do you understand what a phanse difference
> is?? It is timing like you said.
Mike
Nice weblink. Someone went to a lot of work to do the programming and
all for it. When I had phase and rotation and the resultants presented
to me a long time ago it was on a blackboard by a math person. Took a
while to sink in with all of us in the class.
I do undrstand what a phase difference is. I have been tripped up lots
of times by it. One time that comes to my mind was when I was working
in a 3 phase box and simply couldn't get a there phase subpanel to
give me three hot legs as I expected. I found out that a major airport
used nothing but 3 phase panels for distribution but only distributed
two phases of the three. They used the vacant pole in the panel for
growth. There was even a mix of 110 and 220 volts. Thus the panel had
one phase on the first pole and the other poles were the same phase.
Cost the US government a few thousand which was recovered from the
municipality with penalties.
And to "add" to this discussion I am filtering the responses by my
personal criteria. There are 3 ways of doing anything. The adult way,
the child way and the infant way. Take a look at some of the
responses. Civil and not so civil. Our leaders thrust on "civility" is
long over due.
Bob AZ
David Nebenzahl
> David Nebenzahl wrote:
>
>> On 1/26/2011 7:45 PM Michael A. Terrell spake thus:
>>
>>> Michael Kennedy wrote:
>>>
>>>>> MIke et al
>>>>>
>>>>> The problem seems to be that after all this dialogue, that so
>>>>> many of the responders simply don't stick to the basic
>>>>> premise that different phases by definition have timing
>>>>> differences. Simply reversing the way of using a phase does
>>>>> not make it a different phase. The timing stays the same.
>>>>
>>>> Ok I get what your saying.. But do you understand what a phanse
>>>>
difference
>>>> is?? It is timing like you said..
>>>>
>>>> Here is an explanation using audio waves. Maybe you can get
>>>> what I am saying.
>>>>
>>>> http://www.indiana.edu/~emusic/acoustics/phase.htm
>>>
>>> By your definiton, a 'Push-Pull Output Transformer' is two
>>> phase.
>>
>> It IS two phase; that's the whole point. (At least on the primary side.)
>
> Then a Williamson 'Ultra linear' output transformer is four phase?
>
> <http://www.pmillett.com/file_downloads/stancor_ul_schematics.pdf>
>
> See page 4 for a sample schmatic.
I looked at your Stancor PDF. Why in the world would you think I'd think
that transformer is 4-phase???
[btw, the schematics are on pages 2 and 6]
OK, I'll play along here. On page 6 they show an output xfmr with 2
taps. But of course that has nothing whatever to do with phase, as you
damn well know, because the output is referenced to one of the OUTER
LEGS OF THE TRANSFORMER (see that "COM" on the bottom?), so the output
is simply one phase. I was talking about a center-tapped transformer
where the two sides are referenced to THE CENTER TAP.
So again, how does a center-tapped transformer secondary WHERE THE
OUTPUT IS REFERENCED TO THE CENTER TAP (i.e., the center tap is
grounded) NOT generate two separate phases? Please 'splain that.
William Sommerwerck
> THE OUTPUT IS REFERENCED TO THE CENTER TAP
> phases?
After thinking about this, I've come to the conclusion that it doesn't.
"Phase" implies a relative-timing relationship. Simply inverting polarity
doesn't change the timing between the two waveforms.
Bill K7NOM
see that the two signals have different timing.
Bill K7NOM
William Sommerwerck
news:rnC0p.58707$be....@newsfe05.iad...
> William Sommerwerck wrote:
No more than your image in a mirror is a separate being.
David Nebenzahl
That can't be correct.
Let's test the hypothesis. If we had two signals that were 179° out of
phase, would you not say that we had two separate phases? There is a
definite, though small, timing difference.
Let's say the signals were 181° out of phase: two phases again, correct?
So what's "special" or magic about 180° that it wouldn't be considered a
completely separate and distinct phase? Why would phase have a "hole" at
180°? (And for any wisenheimers who will say "well, you must consider 0°
to be a separate phase too!" I say nonsense: that's just a phase
"identity" which we can ignore as being identical to the original phase.)
People seem to be tripped up by the fact that it's trivially easy to
produce the 180° phase, and that it is, as you say, a mirror image of
its respective phase. But this doesn't make it any less of a separate phase.
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.
Even if it's not called that. Even if it is not used *as a phased
system* (it's used to derive two legs from a step-down transformer in a
120-0-120 arrangement). It's still 2-phase power.
So whaddya say now?
David Nebenzahl
> 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?).
Mark Cross
> On 1/28/2011 6:38 AM William Sommerwerck spake thus:
>
>>> How does a center-tapped transformer secondary WHERE
>>> THE OUTPUT IS REFERENCED TO THE CENTER TAP
>>> (ie, the center tap is grounded) NOT generate two separate
>>> phases?
>>
>> After thinking about this, I've come to the conclusion that it doesn't.
>>
>> "Phase" implies a relative-timing relationship. Simply inverting polarity
>> doesn't change the timing between the two waveforms.
>
> That can't be correct.
>
> Let's test the hypothesis. If we had two signals that were 179° out of
> phase, would you not say that we had two separate phases? There is a
> definite, though small, timing difference.
>
> Let's say the signals were 181° out of phase: two phases again, correct?
>
> So what's "special" or magic about 180° that it wouldn't be considered a
> completely separate and distinct phase? Why would phase have a "hole" at
> 180°? (And for any wisenheimers who will say "well, you must consider 0°
> to be a separate phase too!" I say nonsense: that's just a phase
> "identity" which we can ignore as being identical to the original phase.)
Repeat the hypothesis a 0º and you will find a hole in there, much the same
as there must be one at 180º.
To understand what is "magical" about that you will need to know phasors and
the math related to that. Once you understand the math that support phasors,
you clearly see why 0º and 180º are the same phasor.
http://en.wikipedia.org/wiki/Phasor
> People seem to be tripped up by the fact that it's trivially easy to
> produce the 180° phase, and that it is, as you say, a mirror image of
> its respective phase. But this doesn't make it any less of a separate
> phase.
>
> 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.
>
> Even if it's not called that. Even if it is not used *as a phased
> system* (it's used to derive two legs from a step-down transformer in a
> 120-0-120 arrangement). It's still 2-phase power.
>
> So whaddya say now?
No, it isn't.
--
Mark Cross
If Linux doesn't have the solution, you have the wrong problem.
Phil Allison
"William Sommerwerck"
> "Phase" implies a relative-timing relationship.
** The term " phase shift " generally has that implication - but not the
term " phase " alone.
> Simply inverting polarity doesn't change the timing between the two
> waveforms.
** Irrelevant - see above.
In any case, for continuous sinewaves a 180 degree phase shift and signal
polarity inversion are completely indistinguishable.
.... Phil
David Nebenzahl
> David Nebenzahl wrote:
>
>> So what's "special" or magic about 180° that it wouldn't be considered a
>> completely separate and distinct phase? Why would phase have a "hole" at
>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>> to be a separate phase too!" I say nonsense: that's just a phase
>> "identity" which we can ignore as being identical to the original phase.)
>
> Repeat the hypothesis a 0º and you will find a hole in there, much the same
> as there must be one at 180º.
I don't think so. At 0º, the two waveforms are *identical*, so that's
the degenerate case.
> To understand what is "magical" about that you will need to know phasors and
> the math related to that. Once you understand the math that support phasors,
> you clearly see why 0º and 180º are the same phasor.
>
> http://en.wikipedia.org/wiki/Phasor
Sorry, I don't use Wikipedia as a source of credible information.
But even if 0º and 180º are the same phasor, they're still completely
different waveforms, which is the important thing here, isn't it?
Mark Cross
> On 1/28/2011 11:28 AM Mark Cross spake thus:
>
>> David Nebenzahl wrote:
>>
>>> So what's "special" or magic about 180° that it wouldn't be considered a
>>> completely separate and distinct phase? Why would phase have a "hole" at
>>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>>> to be a separate phase too!" I say nonsense: that's just a phase
>>> "identity" which we can ignore as being identical to the original
>>> phase.)
>>
>> Repeat the hypothesis a 0º and you will find a hole in there, much the
>> same as there must be one at 180º.
>
> I don't think so. At 0º, the two waveforms are *identical*, so that's
> the degenerate case.
>
>> To understand what is "magical" about that you will need to know phasors
>> and the math related to that. Once you understand the math that support
>> phasors, you clearly see why 0º and 180º are the same phasor.
>>
>> http://en.wikipedia.org/wiki/Phasor
>
> Sorry, I don't use Wikipedia as a source of credible information.
Open your mind.
> But even if 0º and 180º are the same phasor, they're still completely
> different waveforms, which is the important thing here, isn't it?
No.
bud--
> On 1/28/2011 11:28 AM Mark Cross spake thus:
>
>> David Nebenzahl wrote:
>>
>>> So what's "special" or magic about 180° that it wouldn't be considered a
>>> completely separate and distinct phase? Why would phase have a "hole" at
>>> 180°? (And for any wisenheimers who will say "well, you must consider 0°
>>> to be a separate phase too!" I say nonsense: that's just a phase
>>> "identity" which we can ignore as being identical to the original
>>> phase.)
So you get 2 phases out of a single phase power transformer?
With 2 separate secondary windings there are 2 phases. Winding A is not
the same as winding B.
With 3 separate secondary windings there are 3 separate phases. Winding
A is not the same as winding B. And winding C is not the same as A. And
C is not the same as B.
With 4 separate secondary windings there are 4 phases. ....
Your transformer supplier can furnish a single core transformer with 4
secondary phases?
Your transformer supplier can furnish a single-core transformer with 2
secondary phases?
>
>> To understand what is "magical" about that you will need to know
>> phasors and the math related to that. Once you understand the math
>> that support phasors, you clearly see why 0º and 180º are the same
>> phasor.
>>
>> http://en.wikipedia.org/wiki/Phasor
>
> Sorry, I don't use Wikipedia as a source of credible information.
Then use your own knowledge of phasors. The representation of a 120/240V
service (relative to N) is +120 and -120, both real. There are no
imaginary components. Plus and minus relationships.
>
> But even if 0º and 180º are the same phasor, they're still completely
> different waveforms, which is the important thing here, isn't it?
>
Completely different waveforms? Plus sine is a completely different
waveform from minus sine. Have you taken trigonometry? On a transformer
secondary the relative relationships are locked at plus or minus. 180
degrees is trivial.
When you are doing calculations on a simple single-phase resistive
system you use phase angles? Most of us use plus and minus signs. With
non-resistive elements phasors are used - see above.
You can, of course, call it whatever you want to. Just expect
communication problems. I remember 2 people here who agree with you. It
is not the only 2 people I would want agreeing with me. Maybe you could
shop around to a different newsgroup - maybe alt.engineering.electrical?
And two-phase does still exist. Some relatively small 3-phase to 3-phase
transformers (like 480/277 to 208/120) connect 2 transformers in a Scott
(T) connection. The transformers are an intermediate 2-phase. That is,
real 2-phase - 90 degrees between the voltages
--
bud--
Jamie
> David Nebenzahl wrote:
>
>> On 1/28/2011 11:28 AM Mark Cross spake thus:
>>
>>> David Nebenzahl wrote:
>>>
>>>> So what's "special" or magic about 180° that it wouldn't be
>>>> considered a
>>>> completely separate and distinct phase? Why would phase have a
>>>> "hole" at
>>>> 180°? (And for any wisenheimers who will say "well, you must
>>>> consider 0°
>>>> to be a separate phase too!" I say nonsense: that's just a phase
>>>> "identity" which we can ignore as being identical to the original
>>>> phase.)
>
>
> So you get 2 phases out of a single phase power transformer?
> With 2 separate secondary windings there are 2 phases. Winding A is not
> the same as winding B.
>
> With 3 separate secondary windings there are 3 separate phases. Winding
> A is not the same as winding B. And winding C is not the same as A. And
> C is not the same as B.
>
> With 4 separate secondary windings there are 4 phases. ....
>
> Your transformer supplier can furnish a single core transformer with 4
> secondary phases?
> Your transformer supplier can furnish a single-core transformer with 2
> secondary phases?
>
>>
>>> To understand what is "magical" about that you will need to know
>>> phasors and the math related to that. Once you understand the math
>>> that support phasors, you clearly see why 0º and 180º are the same
>>> phasor.
>>>
>>> http://en.wikipedia.org/wiki/Phasor
>>
>>
>> Sorry, I don't use Wikipedia as a source of credible information.
>
>
> Then use your own knowledge of phasors. The representation of a 120/240V
> service (relative to N) is +120 and -120, both real. There are no
> imaginary components. Plus and minus relationships.
>
>>
>> But even if 0º and 180º are the same phasor, they're still
>> completely different waveforms, which is the important thing here,
>> isn't it?
>>
>
>
> Completely different waveforms? Plus sine is a completely different
> waveform from minus sine. Have you taken trigonometry? On a transformer
> secondary the relative relationships are locked at plus or minus. 180
> degrees is trivial.
>
> When you are doing calculations on a simple single-phase resistive
> system you use phase angles? Most of us use plus and minus signs. With
> non-resistive elements phasors are used - see above.
>
> You can, of course, call it whatever you want to. Just expect
> communication problems. I remember 2 people here who agree with you. It
> is not the only 2 people I would want agreeing with me. Maybe you could
> shop around to a different newsgroup - maybe alt.engineering.electrical?
>
>
> And two-phase does still exist. Some relatively small 3-phase to 3-phase
> transformers (like 480/277 to 208/120) connect 2 transformers in a Scott
> (T) connection. The transformers are an intermediate 2-phase. That is,
> real 2-phase - 90 degrees between the voltages
>
Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
degree's isn't?
Look at power generators (portables), most of them have 2 circuits
from the generator 180 out from each other.. Why is this any different
from a
generator of 90 degrees out ? You can combine a leg of each output from
a those generators also..
It's argument that you won't win from those that truly understand the
meaning of phase angle supplies and the number of supply legs.
Its clear that the maximum you can obtain is only 2 phase angles from
any combination of CT's on a transformer supplied from a single phase
leg how ever, the number of circuits from a transformer can be endless
but not practical, of course.
Michael A. Terrell
Jamie wrote:
>
> bud-- wrote:
>
> > David Nebenzahl wrote:
> >
> >> On 1/28/2011 11:28 AM Mark Cross spake thus:
> >>
> >>> David Nebenzahl wrote:
> >>>
> >>>> considered a
> >>>> completely separate and distinct phase? Why would phase have a
> >>>> "hole" at
> >>>> consider 0°
> >>>> to be a separate phase too!" I say nonsense: that's just a phase
> >>>> "identity" which we can ignore as being identical to the original
> >>>> phase.)
> >
> >
> > So you get 2 phases out of a single phase power transformer?
> > With 2 separate secondary windings there are 2 phases. Winding A is not
> > the same as winding B.
> >
> > With 3 separate secondary windings there are 3 separate phases. Winding
> > A is not the same as winding B. And winding C is not the same as A. And
> > C is not the same as B.
> >
> > With 4 separate secondary windings there are 4 phases. ....
> >
> > Your transformer supplier can furnish a single core transformer with 4
> > secondary phases?
> > Your transformer supplier can furnish a single-core transformer with 2
> > secondary phases?
> >
> >>
> >>> To understand what is "magical" about that you will need to know
> >>> phasors and the math related to that. Once you understand the math
> >>> phasor.
> >>>
> >>> http://en.wikipedia.org/wiki/Phasor
> >>
> >>
> >> Sorry, I don't use Wikipedia as a source of credible information.
> >
> >
> > Then use your own knowledge of phasors. The representation of a 120/240V
> > service (relative to N) is +120 and -120, both real. There are no
> > imaginary components. Plus and minus relationships.
> >
> >>
This, from an illiterate ham radio junkie?
Mark Cross
> Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> degree's isn't?
Because the decomposition of two 90º phasor contains an imaginary part.
Without a real part AND an imaginary part, no distinct phases could be
constructed or generated.
There is no imaginary part in the decomposition of two 180º apart vectors,
and, therefore there is no way to construct other phases (phasors).
Sorry, you need to know phasors to understand this principle.
Jamie
> Jamie wrote:
>
>
>>Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
>>degree's isn't?
>
>
> Because the decomposition of two 90º phasor contains an imaginary part.
> Without a real part AND an imaginary part, no distinct phases could be
> constructed or generated.
>
> There is no imaginary part in the decomposition of two 180º apart vectors,
> and, therefore there is no way to construct other phases (phasors).
>
> Sorry, you need to know phasors to understand this principle.
>
This must be what separates the Electronic and the Fuse puller EE.
I once thought to be an Electrical Engineer or hold an E1 meant, that
you had to know a lot about electricity, evidently you don't. Might be a
good reason why we find it hard to hire some one for a basic electrical
maintenance job that actual understands electrical theory, not many here.
Jamie
Michael A. Terrell
Jamie wrote:
>
> Mark Cross wrote:
>
> > Jamie wrote:
> >
> >
> >>Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> >>degree's isn't?
> >
> >
> > Without a real part AND an imaginary part, no distinct phases could be
> > constructed or generated.
> >
> > and, therefore there is no way to construct other phases (phasors).
> >
> > Sorry, you need to know phasors to understand this principle.
> >
>
> This must be what separates the Electronic and the Fuse puller EE.
>
> I once thought to be an Electrical Engineer or hold an E1 meant, that
> you had to know a lot about electricity, evidently you don't. Might be a
> good reason why we find it hard to hire some one for a basic electrical
> maintenance job that actual understands electrical theory, not many here.
Actually, you can't find enough idiots willing to kiss your stupid
ass.
Mark Cross
> that
> you had to know a lot about electricity, evidently you don't.
I am not looking for a job, much less in basic electrical maintenace. You
may apply if you feel competent for such simple jobs.
Jeffrey Angus
> Yes, 2 phase of 90 degree's still exist, so why is that ok but 180
> degree's isn't?
Because it's STILL a SINGLE phase across the transformer.
> Look at power generators (portables), most of them have 2 circuits from
> the generator 180 out from each other.. Why is this any different from a
> generator of 90 degrees out ? You can combine a leg of each output from
> a those generators also..
I serious doubt they make 90 Degree 2-phase generators.
As to combining multiple output windings from a SINGLE phase
generator, the output is STILL single phase.
> It's argument that you won't win from those that truly understand the
> meaning of phase angle supplies and the number of supply legs.
You're right, _YOU_ won't win that argument.
On combining multiple phases...
On more occasions than I care to recall, I've seen some poor
schmuck buy a 3-5 HP 240 VAC single phase motor, either on a
table saw or an air compressor, and have his "electrician
buddy" give him two of the 120 volt phases of the 3-phase
power in the shop to run his new equipment with.
Aside from the obvious, the voltage is 208 (Not 240), there's
a 120 phase difference between the two leads feeding the motor.
I usually get called in about 2-3 weeks on a "warranty request"
for said motor that just went up in flames.
Jeff
Michael A. Terrell
I recently got a call about a pipe bending machine reporting low
voltage. Rated for 208 to 240 volts and was working fine a couple days
earlier, before it was moved to a new building. They insisted the
wiring was fine, and asked me to add a boost transformer. I did, and it
still didn't work. I finally convinced them to let me check the
voltage. I had 154 volts after the boost transformer, so i went to the
new three phase breaker box and found that someone like Jamie had wired
it. The black wire went to a single pole breaker, and the red went to
neutral. The business owner finally got hold of the company that did
the wiring, who insisted they did the job the right way. When they were
informed that they had used a single pole breaker, they called him a
liar but reluctantly agreed to send out a worker. Three hours later, he
shows up, admits they used the wrong breaker and promised to be back
'sometime next week'. After another couple calls, the owner of the
electrical business delivers the proper breaker. Guess who will ever be
called for any more work?
With 208 going to the boost transformer, I had 244 volts to the
machine. The operator's eyes went wide when he used it. He said it was
working about 50% faster, and bending at the speed it was supposed to.
It had never worked at full speed in the 10+ years they had owned it.
As far as the knuckle draggers:
You can buy single pole breakers.
You can buy double pole breakers.
You can buy three phase breakers.
--- BUT ---
You can't buy two phase breakers.
Phil Allison
"Mark Cross"
>
> To understand what is "magical" about that you will need to know phasors
> and
> the math related to that. Once you understand the math that support
> phasors,
> you clearly see why 0º and 180º are the same phasor.
** ABSOLUTE Bollocks.
> http://en.wikipedia.org/wiki/Phasor
** Says nothing of the kind whatever.
( Bet the only "phasors" this jerk knows about are the ones used on "Star
Trek")
Fuck of you pathetic, bloody TROLL 1!
..... Phil
David Nebenzahl
>"Mark Cross"
>>
>> To understand what is "magical" about that you will need to know
>> phasors and the math related to that. Once you understand the math
>> that support phasors, you clearly see why 0� and 180� are the same
>> phasor.
>
> ** ABSOLUTE Bollocks.
>
>> http://en.wikipedia.org/wiki/Phasor
>
> ** Says nothing of the kind whatever.
>
> ( Bet the only "phasors" this jerk knows about are the ones used on "Star
> Trek")
>
> Fuck of you pathetic, bloody TROLL 1!
Phil, I happen to agree with you here, so do you think you could try to
restrain yourself a little bit and not go off the deep end? Tends to
ruin whatever good points you make ...
Jamie
> On 1/29/2011 5:35 PM Phil Allison spake thus:
>
>> "Mark Cross"
>>
>>>
>>> To understand what is "magical" about that you will need to know
>>> phasors and the math related to that. Once you understand the math
>>> that support phasors, you clearly see why 0º and 180º are the same
>>> phasor.
>>
>>
>> ** ABSOLUTE Bollocks.
>>
>>> http://en.wikipedia.org/wiki/Phasor
>>
>>
>> ** Says nothing of the kind whatever.
>>
>> ( Bet the only "phasors" this jerk knows about are the ones used on
>> "Star Trek")
>>
>> Fuck of you pathetic, bloody TROLL 1!
>
>
> Phil, I happen to agree with you here, so do you think you could try to
> restrain yourself a little bit and not go off the deep end? Tends to
> ruin whatever good points you make ...
>
>
Yes, Phil is correct in his insertion how ever, you can't teach a lot
to fuse pullers, I don't know why Phil even tries.
Jamie
Phil Allison
"David Nebenzahl"
>>"Mark Cross"
>>>
>>> To understand what is "magical" about that you will need to know phasors
>>> and the math related to that. Once you understand the math
>>> that support phasors, you clearly see why 0� and 180� are the same
>>> phasor.
>>
>> ** ABSOLUTE Bollocks.
>>
>>> http://en.wikipedia.org/wiki/Phasor
>>
>> ** Says nothing of the kind whatever.
>>
>> ( Bet the only "phasors" this jerk knows about are the ones used on "Star
>> Trek")
>>
>
> Phil, I happen to agree with you here, so do you think you could try to
> restrain yourself a little bit and not go off the deep end? Tends to ruin
> whatever good points you make ...
** Cross has been posting this same sort of brain dead drivel here for
ears - he is totally off with the fairies and beyond all help. There is no
reason whatever to tolerate such vexatious persons.
I see it as a great folly for anyone to do that.
PS:
Usenet is not the real world - usenet is an on-line jungle.
In normal life, I am usually a polite and cheerful person.
..... Phil
Phil Allison
"David Nebenzahl"
>
> 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?).
** Remember the BBC 1960s TV show:
" Never mind the quality - feel the width "
.... Phil