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Thread: L1 and L2!!

  1. #14
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    This was getting pretty tech heavy for the AOP Forums.

    I moved it over to Tech to Tech as the OP seems to be a tech.

  2. #15
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    Quote Originally Posted by jpsmith1cm View Post
    This was getting pretty tech heavy for the AOP Forums.

    I moved it over to Tech to Tech as the OP seems to be a tech.
    Good idea.
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    2 Tim 3:16-17

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  3. #16
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    Quote Originally Posted by timebuilder View Post
    I'll have to check it tonight.
    Okay. Here's what you posted in #6:

    The start capacitor is wired through the common of the run capacitor, then feeds to the relay, then the start winding and relay are connected through the hermetic terminal of the run capacitor? Then counter EMF backfeeds to open 'normally-closed' to throw out the start capacitor. In this cirumstance, however, isn't voltage still going into the start winding?
    Voltage is ALWAYS going to the start winding.

    The run cap is always in series with the start winding, and the potential relay places the start cap in parallel with the run cap to increase starting torque.

    Phase is the word used to describe the difference in the voltage and the current components of an AC waveform. The capacitors are being used to create an artificial "second" phase, by causing a lag in voltage waveform in the Start winding when compared to the unaltered waveform in the Run winding, helping the rotor to turn against its own inertia and any vapor load in the compressor during startup.
    Last edited by timebuilder; 11-29-2011 at 07:43 PM.
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    2 Tim 3:16-17

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  4. #17
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    Quote Originally Posted by jpsmith1cm View Post
    This was getting pretty tech heavy for the AOP Forums.

    I moved it over to Tech to Tech as the OP seems to be a tech.
    Thanks for moving the thread JP, it was extremely frustrating reading a "basic fundamentals" thread and not being able to respond because I'm not an "asterisk".
    B.O. = B.S.

  5. #18
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    Eye in the sky...I can relate to your questions and confusion because I, too, was confused years ago about some of the terminology, and understanding how a motor circuit works. Don't get hung up on which line connection, L1 or L2, is power in. They both are, but they alternate back and forth 120 times a second. When L1 is "power in", L2 is "power out", and a 120th of a second later, they swap and L1 is "power out" and L2 is now "power in". Like Timebuilder said, "a circuit is a circle" that must be completed. We don't normally show the full circuit because we would have to show the power company's secondary transformer winding out at the pole which is part of the circuit. But electrons come out of the transformer, thru our circuit and back out to the transformer to complete the circle.

    So...did your questions in post #1 get answered by Timebuilder in post #3?
    B.O. = B.S.

  6. #19
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    Smile

    Quote Originally Posted by snewman24 View Post
    Eye in the sky...I can relate to your questions and confusion because I, too, was confused years ago about some of the terminology, and understanding how a motor circuit works. Don't get hung up on which line connection, L1 or L2, is power in. They both are, but they alternate back and forth 120 times a second. When L1 is "power in", L2 is "power out", and a 120th of a second later, they swap and L1 is "power out" and L2 is now "power in". Like Timebuilder said, "a circuit is a circle" that must be completed. We don't normally show the full circuit because we would have to show the power company's secondary transformer winding out at the pole which is part of the circuit. But electrons come out of the transformer, thru our circuit and back out to the transformer to complete the circle.

    So...did your questions in post #1 get answered by Timebuilder in post #3?
    Yeah, they are answered. thanks alot

  7. #20
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    Quote Originally Posted by eye in the sky View Post
    Yeah, they are answered. thanks alot

    Cool.

    You are four posts away from applying for Pro membership.
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  8. #21
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    Cool, I'm going to do that. Looks like I'm going to be referring to the Electrical Fundamentals and study phase because it has me confused at this point, lol.

  9. #22
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    Quote Originally Posted by eye in the sky View Post
    Cool, I'm going to do that. Looks like I'm going to be referring to the Electrical Fundamentals and study phase because it has me confused at this point, lol.
    Here's a really good webpage that shows animations of AC induction motors that makes it easier to see how they work and what's going on. Scroll down to the AC motor section.

    http://www.animations.physics.unsw.e...nductionmotors

    You'll notice that you have 2 sets of poles. The run/main/primary winding poles are at the 12 o'clock and 6 o'clock positions. The start/auxiliary/secondary windings are fed by a run capacitor and are at the 9 o'clock and 3 o'clock positions. Watch the animation and see how the stationary (stator) poles continually change their polarity in a counter-clockwise direction. Opposite magnetic poles attract so as the poles change to blue in a CCW motion, the opposite pole (red) of the rotor is attracted to this and follows the blue as it rotates in a circle, and thus causes the the motor to spin. Also notice that the "start" poles are physically located at an angle 90 degrees from the "run" poles. This why we use a run capacitor to change the phase or "timing" of when the start poles are at their maximum magnetic attraction. It allows them to coordinate their magnetic action in concert with the run poles so that they all work together to produce a circular action with their changing poles. For example the 9 o'clock start pole has it's maximum current, and thus maximum magnetic attraction 90 degrees before the 6 o'clock run winding has IT'S maximum magnetic attraction, with respect to the rotor. They "cooperate" to produce a smooth circular rotational attraction to the rotor (they don't fight each other). Study the animations and the explanation and see if it makes sense to you. If not keeping, keep asking questions.
    B.O. = B.S.

  10. #23
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    Thanks for the link and I will watch it, but while I'm thinking about it, is there really a relevant difference between 'hot' and the 'neutral' wire? I realize what y'all said that since it is alternating electron flow, then while L1 is positive, L2 will be the 'neutral' or completing the circuit back to the transformer and vice versa, correct?

    How does a component (such as the run capacitor) get power while that side of power is acting as a 'neutral'?

  11. #24
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    Quote Originally Posted by eye in the sky View Post
    Thanks for the link and I will watch it, but while I'm thinking about it, is there really a relevant difference between 'hot' and the 'neutral' wire? I realize what y'all said that since it is alternating electron flow, then while L1 is positive, L2 will be the 'neutral' or completing the circuit back to the transformer and vice versa, correct?..........................
    Usually when we talk about L1 & L2 (single phase) we are talking about 240V single phase where both wires are "hot" (ungrounded conductors). The neutral wire is actually a grounded wire (for safety purposes) that is connected all the way back to the transformer (on the pole) to the center tap of the transformer secondary winding, which we use to obtain 120V, and we label it with an "N" to indicate it's a grounded conductor. But, yes, it's still a current carrying conductor just like L1.

    See the following link for a better explanation and see if it answers your questions:

    http://www.apcdistributors.com/white...0Mythology.pdf
    B.O. = B.S.

  12. #25
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    Quote Originally Posted by eye in the sky View Post
    ............................................
    How does a component (such as the run capacitor) get power while that side of power is acting as a 'neutral'?
    If we're still talking about the circuit below, then for purposes of how the motor circuit works there isn't any difference. That circuit would usually be a 240V single phase circuit, where "line" is L1 & the other "line" is L2 and both are "hots" and there is no neutral.

    If the compressor were rate for 120V instead, one "line" would be L1, and the other "line" would be Neutral, "N", because it's connected to the center tap at the transformer, but for all practical purposes nothing has changed except the voltage.

    Don't get hung up on the term "neutral". It's a power wire just like L1 is. It brings power into the run cap just like L1 does. Power comes in thru L1 and leaves thru N, and it also comes in on N and leaves thru L1, alternating back and forth.

    B.O. = B.S.

  13. #26
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    Quote Originally Posted by snewman24 View Post
    Usually when we talk about L1 & L2 (single phase) we are talking about 240V single phase where both wires are "hot" (ungrounded conductors). The neutral wire is actually a grounded wire (for safety purposes) that is connected all the way back to the transformer (on the pole) to the center tap of the transformer secondary winding, which we use to obtain 120V, and we label it with an "N" to indicate it's a grounded conductor. But, yes, it's still a current carrying conductor just like L1.

    See the following link for a better explanation and see if it answers your questions:

    http://www.apcdistributors.com/white...0Mythology.pdf
    Not necessary, that explanation was perfect!

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