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  1. #1
    Join Date
    Mar 2013
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    115 volt compressors

    On a 115v compressor is the common terminal neutral? this is a really basic question i understand that.
    okay let me have it

  2. #2
    Join Date
    Jul 2011
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    Lehigh Valley, PA
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    465
    No. Common should be your 115v hot
    Last edited by Capz; 08-05-2013 at 06:23 PM. Reason: Spellcheck

  3. #3
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    Feb 2009
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    Tallahassee, FL
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    Typically no. The external overload is usually line which is typically hooked to common.

    Neutral usually goes to relay/ run capacitor.

  4. #4
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    Mar 2013
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    Maine
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    Quote Originally Posted by SBKold View Post
    Typically no. The external overload is usually line which is typically hooked to common.

    Neutral usually goes to relay/ run capacitor.
    I worked on a del field freezer today and replaced start components that another tech had diagnosed as being bad. replaced them all and energized the unit and compressor would not start. i tested for continuity through the windings and had none through start and common or start and run. but had continuity through run and common. but also did not have 115v on common but had 115v on start terminal. did i miss something?
    Last edited by northeastbeast; 08-05-2013 at 07:08 PM.

  5. #5
    Join Date
    Oct 2011
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    Chicagoland Area
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    If you didn't have continuity, you have open windings. A compressor will run with the hot and neutral reversed.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  6. #6
    Join Date
    Mar 2013
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    Maine
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    Quote Originally Posted by 2sac View Post
    If you didn't have continuity, you have open windings.
    okay no matter what that was the case then. thanks 2sac. my boss is always calling me up after the fact and saying "did you do this and that ?" "test this and that?" and i always think i missed something.

  7. #7
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    Maine
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    Quote Originally Posted by 2sac View Post
    A compressor will run with the hot and neutral reversed.
    ahhh, really good to know man! thanks! because thats what i kinda thought i had done

  8. #8
    Join Date
    Oct 2011
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    Chicagoland Area
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    You should be able to diagnose a small tin can in a matter of minutes with your meter. It normally takes more time to access the terminals than it does to check it out. A compressor analyzer will allow you to check for locked rotor without start components. I know your green. Don't over analyze the situation. Remember the basics. If you haven't been taught the basics, it's time to learn them.
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Liberalism-Ideas so good they mandate them

  9. #9
    Join Date
    Mar 2013
    Location
    Maine
    Posts
    487
    Quote Originally Posted by 2sac View Post
    You should be able to diagnose a small tin can in a matter of minutes with your meter. It normally takes more time to access the terminals than it does to check it out. A compressor analyzer will allow you to check for locked rotor without start components. I know your green. Don't over analyze the situation. Remember the basics. If you haven't been taught the basics, it's time to learn them.
    I was positive i was right about the open start winding, then later ,after i had gotten home my boss called me and made me think i missed all kinds of stuff, but yea a compressor analyzer sounds like a good investment. thanks again, your really helpful.

  10. #10
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    Jun 2013
    Location
    N. Canada
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    402
    Quote Originally Posted by northeastbeast View Post
    I was positive i was right about the open start winding, then later ,after i had gotten home my boss called me and made me think i missed all kinds of stuff, but yea a compressor analyzer sounds like a good investment. thanks again, your really helpful.
    Don't waste your money on a "compressor analyser".
    In my opinion, they're used by guys that do not know their basic circuits.

  11. #11
    Join Date
    Oct 2009
    Location
    Raleigh, NC
    Posts
    799
    A compressor analyzer is useful at times when you just want to see if you can start a compressor without the start components or when you have suspect start components. A lot of guys just carry a 3-in-1 with a plug attached to do basically the same thing.

    I have a really old HA-1. I very rarely use it, but when I do I appreciate that I have it.

  12. #12
    Join Date
    Nov 2011
    Location
    St. Louis
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    3,490
    Quote Originally Posted by northeastbeast View Post
    I was positive i was right about the open start winding, then later ,after i had gotten home my boss called me and made me think i missed all kinds of stuff, but yea a compressor analyzer sounds like a good investment. thanks again, your really helpful.
    Sounds like the diagnosing tech missed it and you caught it. And then talked yourself out of it

    Don't forget to check each tap to ground while you have them there in your hands...

  13. #13
    Join Date
    Dec 2010
    Location
    Woodbridge Twp, NJ
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    Just a dumb question, but did you check the common terminal or through the overload? If the overload is open, both the run and start will appear open.
    Every customer you take for granted today will be someone else's tomorrow.

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