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  1. #91
    Join Date
    Aug 2007
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    Vancouver BC Canada
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    605

    Default up n down & up n down.

    Quote Originally Posted by Grumpy2 View Post
    So if I use a oscilloscope I'll see two waveforms?
    yup yup yup
    two wave forms 180 dergrees apart. should sortof look like a DNA helix... unless you are in Europe and some other countries of the world where they use 220-240 volt on a single conductor with a neutral.
    we (in the americas)are 120 volts on one conductor with a neutral.
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    Last edited by SignWave; 12-18-2007 at 06:09 PM.
    Will it weld? I loooove electricity!

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  2. #92
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    Oct 2007
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    Cave Creek Az
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    Default

    Here is what two phase power is
    "Two-phase electrical power was an early 20th century polyphase alternating current electric power distribution system. Two circuits, or "phases", were used, with voltages 90 electrical degrees apart in time. Usually circuits used four wires, two for each phase. Less frequently, three wires were used, with a common wire with a larger-diameter conductor. The generators at Niagara Falls installed in 1895 were the largest generators in the world at the time and were two-phase machines. Some early two-phase generators had two complete rotor and field assemblies, mechanically shifted by 90 mechanical degrees to provide two-phase power."
    "Note that true two phase power, meaning the simultaneous provision of sine wave and cosine wave electricity (that is, 90 degrees out of phase) is no longer widely used. But some people incorrectly describe split single phase services as "two phase", when in fact such services are really still single phase power.

    True two-phase power uses two completely independent pairs of wires. It lost out to three phase power due to the fact that two phase requires four wires total to function, while three-phase only needs three wires. Copper was expensive to manufacture when electrification first started, and the expense of the extra wire needed for two phase to work was a major cost concern."

    Now, if I am not mistaken true two phase power would show on a scope as having a sine wave and cosine wave, not the diagram that is shown.

  3. #93
    Join Date
    Mar 2006
    Location
    Ocean City, Maryland
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    951

    Default

    This post gave me a headache !!!!!!!!!!!!!
    Scott
    HMW [Heavy Metal welding]

  4. #94
    Join Date
    Nov 2007
    Location
    Ontario, Canada
    Posts
    72

    Default

    Quote Originally Posted by walker View Post
    Here is what two phase power is
    "Two-phase electrical power was an early 20th century polyphase alternating current electric power distribution system. Two circuits, or "phases", were used, with voltages 90 electrical degrees apart in time. Usually circuits used four wires, two for each phase. Less frequently, three wires were used, with a common wire with a larger-diameter conductor. The generators at Niagara Falls installed in 1895 were the largest generators in the world at the time and were two-phase machines. Some early two-phase generators had two complete rotor and field assemblies, mechanically shifted by 90 mechanical degrees to provide two-phase power."
    "Note that true two phase power, meaning the simultaneous provision of sine wave and cosine wave electricity (that is, 90 degrees out of phase) is no longer widely used. But some people incorrectly describe split single phase services as "two phase", when in fact such services are really still single phase power.

    True two-phase power uses two completely independent pairs of wires. It lost out to three phase power due to the fact that two phase requires four wires total to function, while three-phase only needs three wires. Copper was expensive to manufacture when electrification first started, and the expense of the extra wire needed for two phase to work was a major cost concern."

    Now, if I am not mistaken true two phase power would show on a scope as having a sine wave and cosine wave, not the diagram that is shown.
    Thanks, walker, I didn't know that. This is a great site. I learn something new everyday. Now, if I can only remember the new stuff.
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  5. #95
    Join Date
    Dec 2007
    Location
    Oklahoma
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    696

    Default "Two" phase

    Yes. The wave forms show the relationship between the opposing legs 180 degrees apart. If there were not two waveforms 180 degrees apart, then you could not obtain 240 volts from two opposing legs of 120 volts.

    Roger
    Last edited by griff01; 12-19-2007 at 06:21 PM. Reason: incorrect spacing

  6. #96
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    Aug 2007
    Location
    Vancouver BC Canada
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    605

    Default

    Quote Originally Posted by walker View Post
    Now, if I am not mistaken true two phase power would show on a scope as having a sine wave and cosine wave, not the diagram that is shown.
    this two phase configuration reminds me of a wheel thats got a big chunk taken out of it..

    kATHUNK KATHUNK KATHUNK......
    Will it weld? I loooove electricity!

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  7. #97
    Join Date
    Oct 2006
    Location
    Mpls, MN
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    1,790

    Default

    While one leg of the single phase waveform is pushing, the other side is inversely neutral. When you take half the single sine wave, and "ground" it (via the neutral) to complete the circuit (a must for electron flow), you will get 0V to +120V and back to 0V in 60 bursts per second on one leg and nothing on the neutral.

    When you want 240V, you take both sides, rather than half of that sine wave, and you bounce between +120V and -120V on either leg, thus you end up with 240V across the load and you eliminate the neutral from the circuit.

    Maybe this is a bit too esoteric? It's the reason single phase is referred to as "split phase." There aren't two phases, there is one phase constantly cycling from positive to negative and back. When you implement the neutral carrier, you cut out the other leg from the circuit.

    What the original posters device does, is cut out the neutral from a pair of opposite legs outlets, and does provide access to true 240V assuming there ARE two legs on the homes service.

    The paranoia from others in this thread about not using a ganged breaker is not entirely well founded either. What you lack with this configuration is a completely dead circuit in the event of a partial overload across the device. One leg could remain hot while the other has tripped. This only presents a danger if you then made contact from the remaining live leg to neutral or ground (completing a 120V circuit). However, this isn't very likely with correct machine frame grounding and wiring practices. You would lose full power through any type of load connected in this manner.

    The real danger is some jackass connecting a 120V load via one of these devices to 240V service. In that case you would probably fry the device in short order.

    This is my take on it, and that is founded in many years of practical and technical electrical experience.

    As an aside: Look into "horizontal blanking" in the NTSC television format (or any horizontal blanking in PAL or what not). They use the sine waves passing from positive to neutral to sync the tv picture in cathode ray tubes. That's part of why we have interlaced pictures.
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  8. #98
    Join Date
    Jun 2006
    Location
    Killingworth,Ct.
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    372

    Default I need drugs!!!!!!!!!

    They gave me tranquizers for my mini back operation Tommorow,
    Is there a Miller record????? 10 pages on 120 ,or as everyone calls it,110! This has to go down in the record book!

  9. #99

    Default

    Tempraiser, I am a former electrician, and I am currently working on my PhD. in Quantum Mechanics; so I have extensive knowledge of electricity and magnetisim, both in application and theory. Amazingly, I have been in a situation similar to yours, and can answer most of your questions.

    However because you are such a pr1ck, I will not. I wouldn't give you the sweat off my arse if you were dying of thirst.

    FU

  10. #100
    Join Date
    Oct 2007
    Location
    Indiana
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    541

    Default

    TROLL
    That is kind of rough.
    Tim Beeker,
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