Hi guys
Been a while since I've been around - got lots to keep me occupied. Got a
question about electricity. Want to run some wires in my shop and was
wondering... In 110volt you have a live wire and nuetral wire, this is also
single phase. In 220volt is there 2 live wires of 110volt each that act as
the others nuetral. Or does is it have two 110volt phases running in one
wire with a nuetral wire. And are both phases in phase or out of phases.
Thx Mat
DJ Delorie wrote:
> Duane Bozarth <[email protected]> writes:
>
>>(That is, the two legs of 240V are generated from a single phase
>>supply.)
>
>
> To make it more amusing, we had a tree fall take out the "ground" wire
> coming to our house, leaving only the Earth ground as a return. We
> have 7200v service (transformer at the house), so this left us with a
> single wire coming up the driveway. Power inside the house seemed
> normal to me, although we weren't using very much of it at the time.
>
> If anyone knows how to get more than one phase out of a single wire
> (plus return), there's a Nobel prize waiting for you.
Your one high voltage (really medium or somewhat low for service) is a single phase
of a larger 3 phase system.
It is used to drive a input of a transformer - the other side is earth ground.
The secondary is then generating single phase voltage - but if there is a center tap,
then the far two ends of the secondary with reference to the center tap are out of phase
and typically 180 degrees. This is 220 service. There are unique transformers that
can generate twisted star voltages and phases but the are not at homes. (Canning factories yes...).
If the center tap is open - and you measure from one end to the other - appearances
change again for the same stuff.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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DJ Delorie wrote:
> "Martin H. Eastburn" <[email protected]> writes:
>
>>Your one high voltage (really medium or somewhat low for service) is
>>a single phase of a larger 3 phase system.
>
>
> Yes, I'm well aware of all that. Heck, I know how to *make* those
> transformers.
>
>
>>The secondary is then generating single phase voltage - but if there
>>is a center tap, then the far two ends of the secondary with
>>reference to the center tap are out of phase and typically 180
>>degrees.
>
>
> Typically? What, on alternate Tuesdays it's only 170 degrees?
Special angles for smart assess on Tuesdays.
Actually - I'm a Physicist. I know that the center tap is not perfect.
So the end phases are not perfect.
That is the fact of manufacture. My brother makes Utility Transformers.
>
>
>>This is 220 service.
>
>
> No, it's 240 service.
IT depends on your high line service and if the high line was kicked up
to allow more power or not.
I have lived using 110, 112, 115, 120, 125, 130 volts on home wall plugs.
>
>
>>There are unique transformers that can generate twisted star
>>voltages and phases
>
>
> No, they can *convert* voltages that are already three phase to other
> three phase voltages. They come in delta and wye configurations. An
> isolation transformer can extract one of the phases and yield a single
> phase service, but no simple transformer can turn N phases into >N
> phases.
>
You don't know poly phase power. Three phase is baby talk to high power
and special power use. 7 and 9 phases is common. The ends of the stars(Wye to advanced versions)
are phase shifted and are tapped. These are used in precision motor control.
Who said simple transformers are used. You did I didn't. Phases are simply
a relative voltage or current measurement with reference to another.
Many places have 220 single ended to Gnd. Two wires. We in the USA, typically
have double ended supplies with a central neutral that we use as a point of
reference.
>
>>but the are not at homes.
>
>
> Maybe not *your* home.
You have 7 or 9 phase ? - wow - I'm surprised. But then maybe you shop is
in a old CANCO plant that used German sheet metal to can presses.
Yes, I have single phase and soon three phase. I have no need for Poly phase
at this time.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Don Murray wrote:
>
>
> Martin H. Eastburn wrote:
>
>
>> Special angles for smart assess on Tuesdays.
>> Actually - I'm a Physicist. I know that the center tap is not perfect.
>> So the end phases are not perfect.
>> That is the fact of manufacture. My brother makes Utility Transformers.
>
>
> It's not really a center tap. There's two separate coils on the
> secondary and for a 240 transformer the 2 coils are in series, and the
> center point is connected to a bushing and brought to the outside of the
> can. The same transformer can be used on a 208 service by parallelling
> the secondary coils inside the can. Didn't your brother explain this to
> you?
>
>
>
>>
>>>
>>>
>>>> This is 220 service.
>>>
>>>
>>>
>>>
>>> No, it's 240 service.
>>
>>
>> IT depends on your high line service and if the high line was kicked up
>> to allow more power or not.
>
>
> More BS. If you have anything to back this up, show me.
>
>
>>
>> I have lived using 110, 112, 115, 120, 125, 130 volts on home wall plugs.
>
>
> More BS. Granted years ago there was 110, and now the service voltage is
> 120 plus or minus 5%. But nowhere in the United States has 130V in wall
> plugs. If they do show me.
>
> Don
> I have been doing line work for 33 years, as an apprentice, lineman,
> line foreman, and for the last 20 years as a troubleshooter for the
> power company.
>
>>
>>>
>>>
>>>> There are unique transformers that can generate twisted star
>>>> voltages and phases
>>>
>>>
>>>
>>>
>>> No, they can *convert* voltages that are already three phase to other
>>> three phase voltages. They come in delta and wye configurations. An
>>> isolation transformer can extract one of the phases and yield a single
>>> phase service, but no simple transformer can turn N phases into >N
>>> phases.
>>>
>>
>> You don't know poly phase power. Three phase is baby talk to high power
>> and special power use. 7 and 9 phases is common. The ends of the
>> stars(Wye to advanced versions)
>> are phase shifted and are tapped. These are used in precision motor
>> control.
>> Who said simple transformers are used. You did I didn't. Phases are
>> simply
>> a relative voltage or current measurement with reference to another.
>> Many places have 220 single ended to Gnd. Two wires. We in the USA,
>> typically
>> have double ended supplies with a central neutral that we use as a
>> point of
>> reference.
>>
>>
>>>
>>>> but the are not at homes.
>>>
>>>
>>>
>>>
>>> Maybe not *your* home.
>>
>>
>> You have 7 or 9 phase ? - wow - I'm surprised. But then maybe you
>> shop is
>> in a old CANCO plant that used German sheet metal to can presses.
>>
>> Yes, I have single phase and soon three phase. I have no need for
>> Poly phase
>> at this time.
>>
>> Martin
>
>
Tish tish - never had 125 or 130 - must live in un-developed area of the
u.s.
I have lived all around the country and over seas - grew up in a town that
was growing left and right.
I just left the left coast were 130 was common due to the explosion of houses
drawing power... More power at the same current...same wire.
I was a professor for years and aided Electric Power and Transmission companies
and Electric service companies in learning and teaching - and understanding odd things.
My lines into this 1500+ deep lot have 4 transformers on them for just me. One for the shop
as my 200amp service, one for the house and its 200amp service and then another line and pole
at the back of the lot (more money wasted - not) with a transformer on each high line.
Yes - I have 2 of a three phase high voltage set. The transformers at the end are there
only for transmission line (as in RF and transmitters...) termination at the far end.
Transients slam those transformers, not mine. They are larger and the secondaries fly in the air.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Don Murray wrote:
>
>
> Martin H. Eastburn wrote:
>
>>
>> Your one high voltage (really medium or somewhat low for service) is a
>> single phase
>> of a larger 3 phase system.
>
> 7200V phase to ground is one leg of a 3 phase 15KV system, which is
> about normal. There is older 4160/2400 primary and there is also higher
> voltage primary. We operate a 20.8KV system that's 12KV phase to ground.
>
>
>>
>> It is used to drive a input of a transformer - the other side is earth
>> ground.
>
>
> His 7200V transformer would be a phase to ground, but the other side
> isn't just grounded, it is either hooked to a primary neutral or most
> likely a common neutral. Both are metallic returns to the substation,
> both are grounded at the substation. Common neutrals are common to the
> primary and the secondary and have 3.5ohm grounds or less every 1000'
> under the main line and at the end of all taps.
>
>
> There are unique
>
>> transformers that
>> can generate twisted star voltages and phases but the are not at
>> homes. (Canning factories yes...).
>
>
> Show me a twisted star. This one pegged my BS meter.
>
>
>
>>
>> Martin
>>
> Don
>
Don -
Sounds like you are in the trade. Guess you didn't see the canning factories bit.
Motors are three or more phase there.
They are 7, 9, 12, 15 - strange stuff. What that is all about is this :
Take your 'normal' three phase WYE or star then part way out on the arms re-direct the phase angle
and then sometimes redirect again the re-direct.
These smaller windings out on the end of the winding (in the circuit) are for shading coils on the
motors, coils, and other controls.
They have their energy in a different time domain as the main line coil. Lead or lag, they are
effective push or pull or pre-initialize and the like.
I have a ton of books to go through to find a twisted design - I thought my Motor repair manual
would have it - but didn't see it, then both electricians and electrical engineers standard handbooks
a quick glance - not yet...
I doubt my steam boiler engineering book has it or my High speed signal propagation boo, has. But it
was extracted once for my college notes and aided an electric company service man (a friend as well)
understand 3 phase with these nasty phases - more wires and binding posts than most.
The instructions stated that a single mis-wire would jam the machine. The pressure was on.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Leo Lichtman wrote:
> "Martin H. Eastburn" wrote a delightful piece of science fiction.
> ^^^^^^^^^^^^^^^^
> Don, it pegged my BS meter, as well. Also my entertainment meter. Martin,
> you are in the wrong forum--this needs to be submitted to
> Rec.Ent.Sciencefiction.
>
>
You guys are just not up to speed on custom large factory Production machines.
I have been turning wood since 1957 on and off. Have to turn a handle for the
2" wide steel wrench I cut with my cnc plasma torch. It will be in Walnut.
I have been designing electronic and electrical things since before that date.
National Science Fair first place winner in 57. That was the weirdest year
in my life. Having 3 wings of B-52's in battle dress form up and head East
while I was on the play yard.
Yes I have seen it - done it - been there and had it done to me.
The CANCO plant - makes cans from sheet metal - that was or still is in Arlington Tx
was the place with this nasty transformer and motor. Three phase normal to nasty.
I think you guys are good in your trade but never ran across this stuff and so
it is out of your background.
Ever see a 10,000 amp Ignatron (Mercury tube with an igniter ) They are used to
electro plate large metal items - like whole cars or truck bodies.
They are getting old now - going to solid state stuff but I bet some are still around.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Leo Lichtman wrote:
> "Martin H. Eastburn" wrote: (clip) I think you guys are good in your trade
> but never ran across this stuff and so it is out of your background. (clip)
> ^^^^^^^^^^^^^^^
> Some of the things I have never seen do not exist.
>
>
Like the sound in the forest or the semi-tractor at the 4-way stop ?
There is a lot of things I haven't and won't also.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Don Murray wrote:
>
>
> Martin H. Eastburn wrote:
>
>> I was a professor for years and aided Electric Power and Transmission
>> companies
>> and Electric service companies in learning and teaching - and
>> understanding odd things.
>>
>> Martin
>>
>
> I'd really like to know the specifics of the odd things. I really have a
> fascination for the odd and unusual in the electrical industry.
>
> Don
>
I was cleaning up my new desk - less than half the size of the older "Everlast"
I have now in the shop. (All metal with a 1939 floor top.) (has the drill holes
for locks and all.) I ran across an old IR - International Rectifier handout -
that I generated years ago. I was a great (and still am) fan of IR. Power!
http://www.irf.com/indexsw.html There are application notes on IGBTS and such that
control power hogs. Motors and heaters...
I'm taking an1045 from http://www.irf.com/technical-info/appnotes.htm#acdc
in the shop to verify or not some full wave power bridges I have.
My old version - General information - Silicon Rectifier Circuit diagrams -
Has six phase - Uses a Wye and a Delta driving a common array of 6 rectifiers each
that are tied anodes to - and cathode (the bar on the rectifier) to either end of
a winding - the delta diodes to one end, wye to the other - the center tap is the +.
I don't see it as a buck or a boost, simply two series inductors that tie together.
(that was a parallel bridge) The series bridge is the same without the inductor
The other odd ball one is the Triple Diametric three phase which has El/Edc - No load rms voltage
divided by no load dc voltage. It matches the full wave center tap supply of 2.22 has a 6f
ripple frequency and a 180 degree conduction cycle.
A double wye - using 6 diodes conducts for only 120 degrees.
some interesting notes - Thyristors - relay controls - on the archive site
http://www.irf.com/technical-info/anarchive.html
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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Don Murray wrote:
>
>
> Martin H. Eastburn wrote:
>
>
>> You guys are just not up to speed on custom large factory Production
>> machines.
>>
>>
>>
>> Martin
>>
>>
>
> Martin
>
> I did see the bit about the canning factory in your other post, and
> dismissed it. The fact of the matter is when your can company or your
> chrome plating company or some of the companies in my service area,
> like, Airco, Blue Diamond, and Aerojet, have a problem with the power
> being served them by the utility, I'm the guy that shows up. Also when
> the Police call when there's a pole in the road that a car's knocked
> down, or the Fire Department calls because they want the power shut off
> to a burning building, or someone calls because they want the power shut
> off to change their panel or a main breaker, or a little old lady calls
> that just changed a fuse and her power still doesn't work, I'm the guy
> that shows up.
>
> I run into a lot of plant mechanics, maintanence workers, maintanence
> engineers, and various other titles that are responsible for the
> electrical systems in their plants, and I'd have to say it runs about
> 70/30 to the ones that have a good understanding of their electrical
> systems and ones that are winging it. I spend a lot of my time educating
> the 30% that don't.
>
> Don
>
Don - both good and bad for you. Nice to be at the forefront of power but
sometimes when fire is flicking in a storm - we want you there last.
I used to live in a Coastal Redwood forest. I always hated to see the
guys come in from the flat land central valley to help out. It was great
training, but very dangerous for them. At home, a bucket truck could do
everything. Only the power station high lines would need special help,
but that was someone else. These young men would have a fallen
Fir that was maybe 48" at 4' across a road being held up by the telephone
line. The power lines snapped the insulators off the poles.
To make things worse, the tree was across a steep narrow road. Cutting
the trunk would allow a killing log to roll and the size was much to big
to 'tie up'. Finally the short end was tied up in a spider web of lines
to every tree they could find. A crane at risk down-hill would hold up
a short section as the big tree saw came to play. That was not for
those to learn, but someday they might be training someone else.
The tree had fallen across most of the width of my property. Tons of limbs.
Martin
--
Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
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"DJ Delorie" <[email protected]> wrote in message
news:[email protected]...
>
> "George" <George@least> writes:
>> Worse than nitpicking, actually.
>
> I did say "pedantic".
>
>> What makes you think that, for instance, the mere proximity of the
>> "120V rms" to the primary means it references the primary?
>
> Er, a degree in electrical and computer engineering? I mean, *I* know
> it refers to the secondary (which is 240v) but standards for such
> drawings make it seem to refer to the primary.
>
>> It's not meant to instruct you how to wire, they refer you to the
>> NEC for that.
>
> I was hoping to make sure everyone else understood that. You never
> know when someone's going to trust a picture and end up getting hurt.
====>I would still like to know if the cat in the black box is alive or
dead? *TIC*
Erwin
In article <[email protected]>, DJ Delorie <[email protected]> wrote:
>
>Duane Bozarth <[email protected]> writes:
>> (That is, the two legs of 240V are generated from a single phase
>> supply.)
>
>To make it more amusing, we had a tree fall take out the "ground" wire
>coming to our house, leaving only the Earth ground as a return. We
>have 7200v service (transformer at the house), so this left us with a
>single wire coming up the driveway. Power inside the house seemed
>normal to me, although we weren't using very much of it at the time.
>
>If anyone knows how to get more than one phase out of a single wire
>(plus return), there's a Nobel prize waiting for you.
No there isn't. It's *been*done*. many times, many ways. google
for "quatrature amplitude modulation", for a _relatively_ easy-to-understand
example.
In article <[email protected]>,
Don Murray <[email protected]> wrote:
>
>Martin H. Eastburn wrote:
>
>> Special angles for smart assess on Tuesdays.
>> Actually - I'm a Physicist. I know that the center tap is not perfect.
>> So the end phases are not perfect.
>> That is the fact of manufacture. My brother makes Utility Transformers.
>
>It's not really a center tap. There's two separate coils on the
>secondary and for a 240 transformer the 2 coils are in series, and the
>center point is connected to a bushing and brought to the outside of the
>can. The same transformer can be used on a 208 service by parallelling
>the secondary coils inside the can. Didn't your brother explain this to you?
>
>>>> This is 220 service.
>>>
>>> No, it's 240 service.
>>
>> IT depends on your high line service and if the high line was kicked up
>> to allow more power or not.
>
>More BS. If you have anything to back this up, show me.
_I_ only have 208V. not 220, or 240. I've got meter readings to back
that claim, *and* utility warning stickers at the meter.
>> I have lived using 110, 112, 115, 120, 125, 130 volts on home wall plugs.
>
>More BS. Granted years ago there was 110, and now the service voltage is
>120 plus or minus 5%. But nowhere in the United States has 130V in wall
>plugs. If they do show me.
You had better not bet money against that 130v. I used to have a calibrated
westinghouse line-voltage monitor that I used wherever I was living.
In one old apartment building (1905 construction) I lived in -- which was less
than 70 ft from the substation -- I had a measured 129.5V on the third floor.
Took some _quite_ fussing at the electric utility to get them to send somebody
out to check the situation. When the _engineer_ finally showed up, he took
one look at the gear sitting on my 'workbench', said "h*ll, you've got better
test gear than I do", and radioed dispatch to roll a service truck to the
substation 'right now'.
In article <[email protected]>,
Leo Lichtman <[email protected]> wrote:
>
>"Robert Bonomi" wrote: (clip) I had a measured 129.5V on the third floor.
>(clip)
>^^^^^^^^^^^^
>Gosh! Think how high it must have been on the FIRST floor.
You just *THINK* you're being a smart-ass. :)
Given the quality of the wiring in the building -- and that I got a measured
seven-volt drop at the wall outlet when I kicked on a piece of gear that
drew a whopping 8 amps -- I *do* expect the first-floor folks _were_ seeing
significantly higher voltages. Simply by virtue of being on significantly
shorter runs of that antique 'house' wiring.
Leif Thorvaldson (in [email protected]) said:
| ====>I would still like to know if the cat in the black box is
| alive or dead? *TIC*
"No"
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html
In article <[email protected]>, DJ Delorie <[email protected]>
wrote:
> "No" <[email protected]> writes:
> > I'm sure if both were starting at same time that sucker would blow
> > pretty quick.
>
> Breakers tend to be heat-based, so a short pulse of over-current is
> usually acceptable. The purpose of breakers is to protect the wiring
> up to the outlet, not to protect the device plugged into it, so they
> try to simulate how much heat the wiring is generating and shut off
> the current before the wire's insulation breaks down.
>
> The only time I've seen a breaker blow "pretty quick" was when it was
> completely shorted.
Accidentally starting my chop-saw while the blade lock was engaged
tripped the breaker PDQ...
In article <[email protected]>,
Leo Lichtman <[email protected]> wrote:
> "Leif Thorvaldson" wrote: I would still like to know if the cat in the
> black box is alive or dead?
> ^^^^^^^^^^^^^^^^
> Unless you know of a third possibility.
This is what the blink tag is for:
<html>
<body>
<p>Schroedinger's cat is <blink>not</blink> dead!</p>
</body>
</html>
Robert Bonomi wrote:
>
> _I_ only have 208V. not 220, or 240. I've got meter readings to back
> that claim, *and* utility warning stickers at the meter.
208V is a common service voltage. You still have 2 120V hot legs to
neutral. You find these in apartment buildings, shopping centers, office
buildings, strip malls and warehouses, but it would be very rare to have
one in a single family dwelling.
>
> You had better not bet money against that 130v. I used to have a calibrated
> westinghouse line-voltage monitor that I used wherever I was living.
>
> In one old apartment building (1905 construction) I lived in -- which was less
> than 70 ft from the substation -- I had a measured 129.5V on the third floor.
>
> Took some _quite_ fussing at the electric utility to get them to send somebody
> out to check the situation. When the _engineer_ finally showed up, he took
> one look at the gear sitting on my 'workbench', said "h*ll, you've got better
> test gear than I do", and radioed dispatch to roll a service truck to the
> substation 'right now'.
>
This just backs up what I'm saying. 130V in a wall outlet is just wrong.
In your case in the apartment building, it was probably a 120/208V
service, in which case the problem was the regulator back at the
substation. Most times when I see 130V on one hot leg, it's a neutral
problem on a 120/240V service.
Don
"john smith" <[email protected]> wrote in message
news:[email protected]...
> Hi guys
>
> Been a while since I've been around - got lots to keep me occupied. Got a
> question about electricity. Want to run some wires in my shop and was
> wondering... In 110volt you have a live wire and nuetral wire, this is
> also single phase. In 220volt is there 2 live wires of 110volt each that
> act as the others nuetral. Or does is it have two 110volt phases running
> in one wire with a nuetral wire. And are both phases in phase or out of
> phases.
>
Rather than risk a short-circuit between brain and fingers, I'll give a URL.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
"DJ Delorie" <[email protected]> wrote in message
news:[email protected]...
>
> "George" <George@least> writes:
>> Rather than risk a short-circuit between brain and fingers, I'll give a
>> URL.
>> http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
>
> Pedantic mistakes in that picture:
Worse than nitpicking, actually. What makes you think that, for instance,
the mere proximity of the "120V rms" to the primary means it references the
primary? It's a case of space, and has no pointer.
It's not meant to instruct you how to wire, they refer you to the NEC for
that.
Now go have a nice warm milk to counteract that nervous caffeine energy.
Leo Lichtman wrote:
>
> "DJ Delorie" wrote: Technically (not that it matters in practice), the hot
> wires are *in phase* but with opposite polarity voltages. (clip)
> ^^^^^^^^^^^^^^^
> If there is ANY difference between two voltages of opposite polarity, and
> two voltages 180 degrees out of phase, I can't find it with an oscilloscope
> or in my mind. I don't think there is any difference, but I may also be a
> pedant.
You're correct there is no difference in observable characteristics,
just a difference in how the two voltages are generated in practice.
(That is, the two legs of 240V are generated from a single phase
supply.)
"Don Murray" wrote: It's not really a center tap. There's two separate
coils on the secondary and for a 240 transformer the 2 coils are in series,
(clip)
^^^^^^^^^^^^^^^^^^
I think what he meant was that the windings on both sides of the center tap
may not be identical. This could be true whether or not it is a literal
"center tap," or an electrical equivalent obtained by hooking two windings
in series, with a lead coming off. This would result in a VERY tiny
inequality in the voltages on both sides of neutral. It would NOT result in
any deviation in the phasing on the two sides of neutral.
This would hold true on Tuesdays, as well as other days of the week.
"DJ Delorie" wrote: Technically (not that it matters in practice), the hot
wires are *in phase* but with opposite polarity voltages. (clip)
^^^^^^^^^^^^^^^
If there is ANY difference between two voltages of opposite polarity, and
two voltages 180 degrees out of phase, I can't find it with an oscilloscope
or in my mind. I don't think there is any difference, but I may also be a
pedant.
DJ Delorie <[email protected]> wrote in news:[email protected]:
> But those details don't matter for our purposes, I'm just being
> pedantic.
In true Usenet-Wreck-ElectricityThread fashion! :)
Martin H. Eastburn wrote:
> I was a professor for years and aided Electric Power and Transmission
> companies
> and Electric service companies in learning and teaching - and
> understanding odd things.
>
> Martin
>
I'd really like to know the specifics of the odd things. I really have a
fascination for the odd and unusual in the electrical industry.
Don
"DJ Delorie" <[email protected]> wrote in message
news:[email protected]...
> "Martin H. Eastburn" <[email protected]> writes:
>> Your one high voltage (really medium or somewhat low for service) is
SNIP ..........
>> There are unique transformers that can generate twisted star
>> voltages and phases
>
> No, they can *convert* voltages that are already three phase to other
> three phase voltages. They come in delta and wye configurations. An
> isolation transformer can extract one of the phases and yield a single
> phase service, but no simple transformer can turn N phases into >N
> phases.
>
>> but the are not at homes.
>
> Maybe not *your* home.
==============================
Technically true, but in practice, a wye primary can be used with a delta
secondary allowing, when rectified, a 12 pulse output rather than the 6
pulse of either the dellta/delta or wye/wye. This feature is used in X-ray
generators to achieve near DC levels at the X-ray tube.
Ken Moon
Webberville, TX.
Martin H. Eastburn wrote:
>
> Your one high voltage (really medium or somewhat low for service) is a
> single phase
> of a larger 3 phase system.
7200V phase to ground is one leg of a 3 phase 15KV system, which is
about normal. There is older 4160/2400 primary and there is also higher
voltage primary. We operate a 20.8KV system that's 12KV phase to ground.
>
> It is used to drive a input of a transformer - the other side is earth
> ground.
His 7200V transformer would be a phase to ground, but the other side
isn't just grounded, it is either hooked to a primary neutral or most
likely a common neutral. Both are metallic returns to the substation,
both are grounded at the substation. Common neutrals are common to the
primary and the secondary and have 3.5ohm grounds or less every 1000'
under the main line and at the end of all taps.
There are unique
> transformers that
> can generate twisted star voltages and phases but the are not at homes.
> (Canning factories yes...).
Show me a twisted star. This one pegged my BS meter.
>
> Martin
>
Don
Martin H. Eastburn wrote:
<snip some not so funny stuff>
Guess it is a case of If you can't dazzle them with brilliance, baffle
them with bull shit.
Lew
> I was cleaning up my new desk - less than half the size of the older
> "Everlast"
> I have now in the shop. (All metal with a 1939 floor top.) (has the
> drill holes
> for locks and all.) I ran across an old IR - International Rectifier
> handout -
> that I generated years ago. I was a great (and still am) fan of IR.
> Power!
> http://www.irf.com/indexsw.html There are application notes on IGBTS and
> such that
> control power hogs. Motors and heaters...
> I'm taking an1045 from http://www.irf.com/technical-info/appnotes.htm#acdc
> in the shop to verify or not some full wave power bridges I have.
>
> My old version - General information - Silicon Rectifier Circuit diagrams -
> Has six phase - Uses a Wye and a Delta driving a common array of 6
> rectifiers each
> that are tied anodes to - and cathode (the bar on the rectifier) to
> either end of
> a winding - the delta diodes to one end, wye to the other - the center
> tap is the +.
> I don't see it as a buck or a boost, simply two series inductors that
> tie together.
> (that was a parallel bridge) The series bridge is the same without the
> inductor
>
> The other odd ball one is the Triple Diametric three phase which has
> El/Edc - No load rms voltage
> divided by no load dc voltage. It matches the full wave center tap
> supply of 2.22 has a 6f
> ripple frequency and a 180 degree conduction cycle.
> A double wye - using 6 diodes conducts for only 120 degrees.
>
> some interesting notes - Thyristors - relay controls - on the archive site
> http://www.irf.com/technical-info/anarchive.html
>
> Martin
>
>
>
>
Martin H. Eastburn wrote:
> Special angles for smart assess on Tuesdays.
> Actually - I'm a Physicist. I know that the center tap is not perfect.
> So the end phases are not perfect.
> That is the fact of manufacture. My brother makes Utility Transformers.
It's not really a center tap. There's two separate coils on the
secondary and for a 240 transformer the 2 coils are in series, and the
center point is connected to a bushing and brought to the outside of the
can. The same transformer can be used on a 208 service by parallelling
the secondary coils inside the can. Didn't your brother explain this to you?
>
>>
>>
>>> This is 220 service.
>>
>>
>>
>> No, it's 240 service.
>
> IT depends on your high line service and if the high line was kicked up
> to allow more power or not.
More BS. If you have anything to back this up, show me.
>
> I have lived using 110, 112, 115, 120, 125, 130 volts on home wall plugs.
More BS. Granted years ago there was 110, and now the service voltage is
120 plus or minus 5%. But nowhere in the United States has 130V in wall
plugs. If they do show me.
Don
I have been doing line work for 33 years, as an apprentice, lineman,
line foreman, and for the last 20 years as a troubleshooter for the
power company.
>
>>
>>
>>> There are unique transformers that can generate twisted star
>>> voltages and phases
>>
>>
>>
>> No, they can *convert* voltages that are already three phase to other
>> three phase voltages. They come in delta and wye configurations. An
>> isolation transformer can extract one of the phases and yield a single
>> phase service, but no simple transformer can turn N phases into >N
>> phases.
>>
>
> You don't know poly phase power. Three phase is baby talk to high power
> and special power use. 7 and 9 phases is common. The ends of the
> stars(Wye to advanced versions)
> are phase shifted and are tapped. These are used in precision motor
> control.
> Who said simple transformers are used. You did I didn't. Phases are
> simply
> a relative voltage or current measurement with reference to another.
> Many places have 220 single ended to Gnd. Two wires. We in the USA,
> typically
> have double ended supplies with a central neutral that we use as a point of
> reference.
>
>
>>
>>> but the are not at homes.
>>
>>
>>
>> Maybe not *your* home.
>
> You have 7 or 9 phase ? - wow - I'm surprised. But then maybe you shop is
> in a old CANCO plant that used German sheet metal to can presses.
>
> Yes, I have single phase and soon three phase. I have no need for Poly
> phase
> at this time.
>
> Martin
220VAC is 2 legs of 110VAC out of phase with each other. Therefore, the
220VAC is across those legs. Sometimes there is also a neutral wire included
which allows the outlet to also offer 110VAC. This configuration is typical
for a cloths dryer where the timer runs on 110VAC and the heaters on 220VAC.
For wiring 220VAC in your shop, I recommend pulling cable with 2 hots, 1
neutral and 1 ground. The motors in your machines don't need the neutral,
but it's handy to have there if you need it in the future.
Bernie
"john smith" <[email protected]> wrote in message
news:[email protected]...
> Hi guys
>
> Been a while since I've been around - got lots to keep me occupied. Got a
> question about electricity. Want to run some wires in my shop and was
> wondering... In 110volt you have a live wire and nuetral wire, this is
> also single phase. In 220volt is there 2 live wires of 110volt each that
> act as the others nuetral. Or does is it have two 110volt phases running
> in one wire with a nuetral wire. And are both phases in phase or out of
> phases.
>
> Thx Mat
>
Martin H. Eastburn wrote:
> You guys are just not up to speed on custom large factory Production
> machines.
>
>
>
> Martin
>
>
Martin
I did see the bit about the canning factory in your other post, and
dismissed it. The fact of the matter is when your can company or your
chrome plating company or some of the companies in my service area,
like, Airco, Blue Diamond, and Aerojet, have a problem with the power
being served them by the utility, I'm the guy that shows up. Also when
the Police call when there's a pole in the road that a car's knocked
down, or the Fire Department calls because they want the power shut off
to a burning building, or someone calls because they want the power shut
off to change their panel or a main breaker, or a little old lady calls
that just changed a fuse and her power still doesn't work, I'm the guy
that shows up.
I run into a lot of plant mechanics, maintanence workers, maintanence
engineers, and various other titles that are responsible for the
electrical systems in their plants, and I'd have to say it runs about
70/30 to the ones that have a good understanding of their electrical
systems and ones that are winging it. I spend a lot of my time educating
the 30% that don't.
Don
"DJ Delorie" wrote: (clip) My primary motivation, other than to have some
fun on a Friday, is to keep people from confusing single-phase house current
with the original two-phase (4 wire, 90 degrees) AC invented by Tesla. This
2-phase was replaced with our current 3-phase (3 wire, 120 degrees) power.
^^^^^^^^^^^^^^^^
I don't think anyone was trying to say that 220v power coming to the house
is "two phase." Two phase power requires a 90 degree lag (or lead) between
the phases.
If you look at two voltages on an oscilloscope, and see one reaching its
positive peak while the other is reaching its negative peak, is one 180
degrees out of phase with the other? According to your thinking, it
depends on the source. If its coming from a center-tapped transformer, it's
not a phase difference, but a polarity reversal. If it's coming from
generator windings that are positioned on opposite sides of the stator, it
would be a 180 degree phase difference.
Suppose its coming out of a black box?
Thats what I did. 10-3, 30A for my 220 TS and 12-3, 20A for my 220 DC. I
then added a few 110 convienience outlets to the DC circuit. I only worry a
bit about tripping my breaker if I move my compressor from its dedicated
110v 20A circuit, for convienience sake ;) , to one of the outlets on my DC
circuit. If the compressor kicks in while DC is on..... has happened once
but never tripped the breaker yet! I'm sure if both were starting at same
time that sucker would blow pretty quick.
-B
"Bernie Hunt" <[email protected]> wrote in message
news:N%[email protected]...
> 220VAC is 2 legs of 110VAC out of phase with each other. Therefore, the
> 220VAC is across those legs. Sometimes there is also a neutral wire
> included which allows the outlet to also offer 110VAC. This configuration
> is typical for a cloths dryer where the timer runs on 110VAC and the
> heaters on 220VAC.
>
> For wiring 220VAC in your shop, I recommend pulling cable with 2 hots, 1
> neutral and 1 ground. The motors in your machines don't need the neutral,
> but it's handy to have there if you need it in the future.
>
> Bernie
>
> "john smith" <[email protected]> wrote in message
> news:[email protected]...
>> Hi guys
>>
>> Been a while since I've been around - got lots to keep me occupied. Got
>> a question about electricity. Want to run some wires in my shop and was
>> wondering... In 110volt you have a live wire and nuetral wire, this is
>> also single phase. In 220volt is there 2 live wires of 110volt each that
>> act as the others nuetral. Or does is it have two 110volt phases running
>> in one wire with a nuetral wire. And are both phases in phase or out of
>> phases.
>>
>> Thx Mat
>>
>
>
"George" <George@least> wrote in message
news:[email protected]...
> Worse than nitpicking, actually.
He did say pedantic, and although I can understand that the drawing takes
liberties for the sake of readability (like not having bus slots zig-zag)
putting a neutral connection on that 240V outlet is just wrong.
-Steve
David C. Stone <[email protected]> wrote:
>In article <[email protected]>, DJ Delorie <[email protected]>
>wrote:
>
>> "No" <[email protected]> writes:
>> > I'm sure if both were starting at same time that sucker would blow
>> > pretty quick.
>>
>> Breakers tend to be heat-based, so a short pulse of over-current is
>> usually acceptable. The purpose of breakers is to protect the wiring
>> up to the outlet, not to protect the device plugged into it, so they
>> try to simulate how much heat the wiring is generating and shut off
>> the current before the wire's insulation breaks down.
>>
>> The only time I've seen a breaker blow "pretty quick" was when it was
>> completely shorted.
>
>Accidentally starting my chop-saw while the blade lock was engaged
>tripped the breaker PDQ...
Breakers are designed with various trip delay curves to suit the
intended application. There's a good overview at
http://tinyurl.com/cffxx. Looking at the curve in Fig 1 of that
article, that particular breaker described looks like it trips in
about 20 seconds for a 2x overload, about 4 seconds for a 5x
overload, and above a 10x overload, the trip time is down in the
mili-second range.
Don Murray <[email protected]> wrote:
>208V is a common service voltage. You still have 2 120V hot legs to
>neutral. You find these in apartment buildings, shopping centers, office
>buildings, strip malls and warehouses, but it would be very rare to have
>one in a single family dwelling.
I used to live in such a building. 54 units, each with two phases run
into the apartment (each line of apartments got a different pair of
phases).
"john smith" <[email protected]> wrote in message
news:[email protected]...
> Hi guys
>
> Been a while since I've been around - got lots to keep me occupied. Got a
> question about electricity. Want to run some wires in my shop and was
> wondering... In 110volt you have a live wire and nuetral wire, this is
> also single phase. In 220volt is there 2 live wires of 110volt each that
> act as the others nuetral. Or does is it have two 110volt phases running
> in one wire with a nuetral wire. And are both phases in phase or out of
> phases.
>
> Thx Mat
>
120V = 1 hot wire and neutral
240V = 2 hot wires, no neutral, one wire has one phase and the other wire
has another phase and its 120 degrees between the two phases
Fred wrote:
> "john smith" <[email protected]> wrote in message
> news:[email protected]...
>
>>Hi guys
>>
>>Been a while since I've been around - got lots to keep me occupied. Got a
>>question about electricity. Want to run some wires in my shop and was
>>wondering... In 110volt you have a live wire and nuetral wire, this is
>>also single phase. In 220volt is there 2 live wires of 110volt each that
>>act as the others nuetral. Or does is it have two 110volt phases running
>>in one wire with a nuetral wire. And are both phases in phase or out of
>>phases.
>>
>>Thx Mat
>>
>
>
> 120V = 1 hot wire and neutral
>
> 240V = 2 hot wires, no neutral, one wire has one phase and the other wire
> has another phase and its 120 degrees between the two phases
>
>
One minor correction: The hot wires are 180 degrees out of phase.
Bill
Ken Moon wrote:
>
> ==============================
> Technically true, but in practice, a wye primary can be used with a delta
> secondary allowing, when rectified, a 12 pulse output rather than the 6
> pulse of either the dellta/delta or wye/wye. This feature is used in X-ray
> generators to achieve near DC levels at the X-ray tube.
>
> Ken Moon
> Webberville, TX.
>
>
Ken
I don't doubt that X-ray machines have special transformers in them for
their needs. But for distribution transformers a wye primary and a delta
secondary is very common, as is a delta primary and a wye secondary. The
determining factor on whether the primary is going to be wye or delta is
the actual line voltage and the nameplate rating on the transformer. For
example, we have a 12KV 3 wire primary that is 12KV phase to phase and
6930V phase to ground. And we also have a 20.8KV 3 wire primary with a
common neutral that is 12KV phase to ground. And we stock 12KV
transformers. So if you are going to hang a bank in the 12KV primary, it
will be delta. And if you hang a bank in the 21KV primary, it will be wye.
The determining factor on whether the secondary is going to be delta or
wye is the voltage that you want to serve. If you are going to serve a
120/240V 3 phase service the secondary will be delta. And if you are
going to serve a 120/208V 3 phase service the secondary will be wye.
Note: to serve a 120/208V service we must pull the lids off the
transformers and parallel the secondary coils inside.
So by stocking 12KV 120/240V transformers we can use these in both
primary systems and serve 120/240V 3 phase, and 120/208V 3 phase and
120/240V single phase.
Next week we'll be covering VARS (volt amps reactive) captive reactance
and inductive reactance, circulating current, fault current, third
harmonic overvoltage, and ferro-resonance. :)
Don
"George" <George@least> wrote in message
news:[email protected]...
>>
> Rather than risk a short-circuit between brain and fingers, I'll give a
URL.
> http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
>
>
That's an excellent diagram. Thanks for posting the link.
Bob
DJ Delorie wrote:
After all, you only have
> one secondary winding on that transformer;
Actually, there are two secondary coils on the transformer, and they're
in series in this application. But there are other times when they are
in parallel. You can have a look at my website, and see some transformer
connections, including phase angles, that I had up for a discussion on
another NG. They are the most common three phase connections used today.
http://murrayranch.com/Electricity.htm
>
> There is such a thing as two-phase power, where the hots are 90
> degrees out of phase (three or four wire systems) but they're obsolete
> these days.
There is also a 5 wire. On my web page you can see the Scott connections
that require special transformers to serve these obsolete loads from
modern three phase power. These are very rare today.
>
> But those details don't matter for our purposes, I'm just being
> pedantic.
So am I :)
Don
"Leif Thorvaldson" <[email protected]> writes:
> ====>I would still like to know if the cat in the black box is alive or
> dead? *TIC*
"Yes"
Bill Rubenstein <[email protected]> writes:
> One minor correction: The hot wires are 180 degrees out of phase.
Technically (not that it matters in practice), the hot wires are *in
phase* but with opposite polarity voltages. After all, you only have
one secondary winding on that transformer; the "neutral" is really a
center tap or halfway-voltage.
There is such a thing as two-phase power, where the hots are 90
degrees out of phase (three or four wire systems) but they're obsolete
these days.
But those details don't matter for our purposes, I'm just being
pedantic.
"Leo Lichtman" <[email protected]> writes:
> If you look at two voltages on an oscilloscope, and see one reaching
> its positive peak while the other is reaching its negative peak, is
> one 180 degrees out of phase with the other?
Since you said "positive peak" and "negative peak", no. Had you said
"most positive" and "least positive", yes.
I think the answer depends more on stuff other than the signals
themselves. If you measure between the signals, and the result isn't
the simple subtraction of the two signals, it's a phase difference.
What if you had a 120VAC signal, and a 12VAC signal of opposite
polarity? Are they out of phase? What about 120VAC and a -12VAC
signal of opposite polarity (the signs cancel and you get the "same"
polarity)? Good thing it doesn't matter in practice. Of course, if
it *did* matter in practice, it would be because of a measurable
difference, and then the answer would be obvious ;-)
My scope has an "invert" switch that further confuses the issue.
> Suppose its coming out of a black box?
Then it doesn't matter. Usually it's a matter of definition, not
evidence. On the schematic, the signals would be labelled relative to
the circuit's common ground, and as to whether they were defined by
voltage or phase. It matters a lot more when the shape of the signal
is asymmetric (like a pulse or ramp). An inverted pulse is *way*
different from an out of phase pulse.
In the case of house current, since we *do* use the 240VAC voltage
offering, the definition is one of voltage, not phase. You use all of
the voltage, or half of it. If you had three phase power, you
couldn't add the three voltages up to get a single 3x voltage, so the
definition is one of phase. You normally have three phase power
because you're taking advantage of the phase differences, not the
range of voltages you get.
Don Murray <[email protected]> writes:
> An autotransformer, we use them all the time to get people in full
> power. All you need are 2 good wires. You can make the third.
That doesn't change phase. But now that I think of it, they do make
phase converters using a motor and a generator.
Duane Bozarth <[email protected]> writes:
> (That is, the two legs of 240V are generated from a single phase
> supply.)
To make it more amusing, we had a tree fall take out the "ground" wire
coming to our house, leaving only the Earth ground as a return. We
have 7200v service (transformer at the house), so this left us with a
single wire coming up the driveway. Power inside the house seemed
normal to me, although we weren't using very much of it at the time.
If anyone knows how to get more than one phase out of a single wire
(plus return), there's a Nobel prize waiting for you.
"Leo Lichtman" <[email protected]> writes:
> If there is ANY difference between two voltages of opposite
> polarity, and two voltages 180 degrees out of phase, I can't find it
> with an oscilloscope or in my mind. I don't think there is any
> difference, but I may also be a pedant.
The relationship is not symmetrical.
It's relatively easy to generate two signals that are 180 degrees out
of phase, each of which can be measured relative to a common ground,
but show no voltage difference relative to each other. Think of two
relays (or light switches) which take turns turning a circuit on. You
can measure the output of either relays' contacts to ground, and see
the signal, but if you just connect from one relay to the other, you
get nothing.
In the case of a multi-tap transformer, the fact that it's a multi-tap
transformer is enough to make it a voltage issue rather than a phase
issue. Consider a transformer with ten taps. Are there ten phases?
Of course not, but there are ten (er, plus or minus a fence post)
voltages, which you can use in any [linear] combination, much like
putting batteries in series.
Now, if you had two identical transformers, and wired one backwards,
*then* you'd have a phase issue (still, though, no practical
difference). But like I said earlier, there's no practical difference
when we're talking about house current.
My primary motivation, other than to have some fun on a Friday, is to
keep people from confusing single-phase house current with the
original two-phase (4 wire, 90 degrees) AC invented by Tesla. This
2-phase was replaced with our current 3-phase (3 wire, 120 degrees)
power.
"No" <[email protected]> writes:
> I'm sure if both were starting at same time that sucker would blow
> pretty quick.
Breakers tend to be heat-based, so a short pulse of over-current is
usually acceptable. The purpose of breakers is to protect the wiring
up to the outlet, not to protect the device plugged into it, so they
try to simulate how much heat the wiring is generating and shut off
the current before the wire's insulation breaks down.
The only time I've seen a breaker blow "pretty quick" was when it was
completely shorted.
"George" <George@least> writes:
> Worse than nitpicking, actually.
I did say "pedantic".
> What makes you think that, for instance, the mere proximity of the
> "120V rms" to the primary means it references the primary?
Er, a degree in electrical and computer engineering? I mean, *I* know
it refers to the secondary (which is 240v) but standards for such
drawings make it seem to refer to the primary.
> It's not meant to instruct you how to wire, they refer you to the
> NEC for that.
I was hoping to make sure everyone else understood that. You never
know when someone's going to trust a picture and end up getting hurt.
"Martin H. Eastburn" <[email protected]> writes:
> Your one high voltage (really medium or somewhat low for service) is
> a single phase of a larger 3 phase system.
Yes, I'm well aware of all that. Heck, I know how to *make* those
transformers.
> The secondary is then generating single phase voltage - but if there
> is a center tap, then the far two ends of the secondary with
> reference to the center tap are out of phase and typically 180
> degrees.
Typically? What, on alternate Tuesdays it's only 170 degrees?
> This is 220 service.
No, it's 240 service.
> There are unique transformers that can generate twisted star
> voltages and phases
No, they can *convert* voltages that are already three phase to other
three phase voltages. They come in delta and wye configurations. An
isolation transformer can extract one of the phases and yield a single
phase service, but no simple transformer can turn N phases into >N
phases.
> but the are not at homes.
Maybe not *your* home.
"George" <George@least> writes:
> Rather than risk a short-circuit between brain and fingers, I'll give a URL.
> http://hyperphysics.phy-astr.gsu.edu/hbase/electric/hsehld.html
Pedantic mistakes in that picture:
* The two mains in the breaker box aren't wired that way. They
zig-zag back and forth so that vertically adjacent breakers are
always on separate mains.
* 24v circuits are always wired with a single ganged breaker that uses
two vertically adjacent slots; it is wrong to wire one 240v outlet to
two separate breakers.
* It is wrong to tie both ground and neutral to the same tie block on
the breaker panel, even when the two blocks are tied together in the
panel.
* The three-hole 240v outlet should have the third hole tied to
ground, not neutral. Only four-hole 240v outlets use neutral.
* The circuit is grounded at two places (the transformer and the
neutral tie block). Only one ground tie-in is permitted per
building. The circuit should be grounded at a *ground* tie block,
with neutral tied to ground at one point (usually the main breaker
box).
* The transformer is labelled "120V RMS" on the primary side, which is
wrong (the primary is usually 7200v or more), and the US standard is
240V not 120V. (The US, unlike Europe, provides a center tap for
lower voltage devices, but the main voltage is the same).