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Wiring question
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 |
#2
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"john smith" wrote in message ... 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 |
#3
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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" wrote in message ... 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 |
#4
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"john smith" wrote in message ... 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...ic/hsehld.html |
#5
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Fred wrote:
"john smith" wrote in message ... 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 |
#6
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"George" George@least wrote in message ... Rather than risk a short-circuit between brain and fingers, I'll give a URL. http://hyperphysics.phy-astr.gsu.edu...ic/hsehld.html That's an excellent diagram. Thanks for posting the link. Bob |
#7
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Bill Rubenstein 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. |
#8
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"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...ic/hsehld.html Pedantic mistakes in that pictu * 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). |
#9
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"DJ Delorie" wrote in message ... "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...ic/hsehld.html Pedantic mistakes in that pictu 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. |
#10
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"George" George@least wrote in message ... 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 |
#11
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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" wrote in message ... 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" wrote in message ... 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 |
#12
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"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. |
#13
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"No" 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. |
#14
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In article , DJ Delorie
wrote: "No" 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... |
#15
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David C. Stone wrote:
In article , DJ Delorie wrote: "No" 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. |
#16
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"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. |
#17
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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.) |
#18
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"Leo Lichtman" 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. |
#19
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Duane Bozarth 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. |
#20
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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 |
#21
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DJ Delorie wrote: 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. 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 |
#22
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Don Murray 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. |
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"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? |
#24
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DJ Delorie wrote in :
But those details don't matter for our purposes, I'm just being pedantic. In true Usenet-Wreck-ElectricityThread fashion! |
#25
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"Leo Lichtman" 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. |
#26
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"DJ Delorie" wrote in message ... "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 |
#27
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DJ Delorie wrote:
Duane Bozarth 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 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#28
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"Leif Thorvaldson" writes: ====I would still like to know if the cat in the black box is alive or dead? *TIC* "Yes" |
#29
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"Martin H. Eastburn" 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. |
#30
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DJ Delorie wrote:
"Martin H. Eastburn" 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 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#32
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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 |
#33
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"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. |
#34
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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 |
#35
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Leif Thorvaldson wrote:
====I would still like to know if the cat in the black box is alive or dead? *TIC* After a 220 volt hit, I'd say that Mr. Shroedenger (sp?) won't need to stock up on the Friskie's any time soon! ;-) ....Kevin -- Kevin Miller http://www.alaska.net/~atftb Juneau, Alaska |
#36
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"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. |
#37
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In article ,
Leo Lichtman 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 pSchroedinger's cat is blinknot/blink dead!/p /body /html |
#38
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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 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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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 ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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In article , DJ Delorie wrote:
Duane Bozarth 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. |
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