# Wiring question

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• posted on August 19, 2005, 8:16 am

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

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<%-name%>
• posted on August 19, 2005, 8:46 am

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

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• posted on August 19, 2005, 10:39 am
Fred wrote:

One minor correction: The hot wires are 180 degrees out of phase.
Bill

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• posted on August 19, 2005, 12:20 pm

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.

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• posted on August 19, 2005, 4:29 pm
"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.

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• posted on August 19, 2005, 4:43 pm
Leo Lichtman wrote:

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.)

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• posted on August 19, 2005, 5:08 pm

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.

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• posted on August 19, 2005, 5:13 pm
DJ Delorie wrote:

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.
Don

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• posted on August 19, 2005, 5:22 pm

That doesn't change phase. But now that I think of it, they do make phase converters using a motor and a generator.

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• posted on August 20, 2005, 2:00 am
DJ Delorie wrote:

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

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• posted on August 20, 2005, 3:14 am

Yes, I'm well aware of all that. Heck, I know how to *make* those transformers.

Typically? What, on alternate Tuesdays it's only 170 degrees?

No, it's 240 service.

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.

Maybe not *your* home.

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• posted on August 20, 2005, 3:48 am
DJ Delorie 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 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.

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.

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

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• posted on August 20, 2005, 4:33 am
Martin H. Eastburn 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, 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?

More BS. If you have anything to back this up, show me.

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.

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• posted on August 20, 2005, 6:06 am
"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.

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• posted on August 21, 2005, 3:22 am
Don Murray wrote:

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

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• posted on August 22, 2005, 6:20 pm
Martin H. Eastburn wrote:

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

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• posted on August 23, 2005, 2:49 am
Don Murray wrote:

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

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• posted on August 23, 2005, 3:19 am
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

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• posted on August 21, 2005, 10:13 pm

_I_ only have 208V. not 220, or 240. I've got meter readings to back that claim, *and* utility warning stickers at the meter.

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'.

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• posted on August 22, 2005, 12:56 am
"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.