Single phase condenser motor running backwards - Page 2
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  1. #14
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    Nov 2006
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    Quote Originally Posted by killer v View Post
    Now I see what you were saying. The motor is definitely running backwards though. The one time I was there, we isolated it and I gave it a spin in the correct direction. My partner pushed in the contact and it spun back the other way.

    Granted, my electrical knowledge isn't quite there yet (more classes coming) but I just can't wrap my head around this one.
    Get your post count up and apply for Pro membership. There are articles there about electricity.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  2. #15
    Join Date
    Apr 2010
    Location
    Northern Illinois
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    19
    The motor will surely be replaced, but I'd like to know what might cause this for my own knowledge.

    Thanks for all the replies!

  3. #16
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    Nov 2006
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    Southeastern Pa
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    Quote Originally Posted by killer v View Post
    The motor will surely be replaced, but I'd like to know what might cause this for my own knowledge.

    Thanks for all the replies!
    For motors with no reversing plug: IF the motor has a good cap and is connected properly, the only remaining reason it will turn in the wrong direction is a problem with the wiring or windings within the motor.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  4. #17
    Join Date
    Jul 2011
    Location
    Canton,Ma
    Posts
    7
    single phase will not run backwards only 3 phase can. if the rpm's look about right, correct the problem with a new fan blade thats meant for the rotation... a little cheaper than a new motor andless work. often most motors the rotation is if you were looking at the butt end of the motor unless it says cwse or ccse that woull be shaft end of the motor. I have run into motors spinning backward such as 9w motors in supermarket evaps, usually can be corrcted by clipping the capacitor wire (which is usually blue) and just having the 120 going to the motors.

  5. #18
    Join Date
    Jan 2011
    Posts
    92
    Quote Originally Posted by BuGnLikeAnInSect View Post
    single phase will not run backwards only 3 phase can. if the rpm's look about right, correct the problem with a new fan blade thats meant for the rotation... a little cheaper than a new motor andless work. often most motors the rotation is if you were looking at the butt end of the motor unless it says cwse or ccse that woull be shaft end of the motor. I have run into motors spinning backward such as 9w motors in supermarket evaps, usually can be corrcted by clipping the capacitor wire (which is usually blue) and just having the 120 going to the motors.
    not entirely true. I was cleaning coils the other day, restarted the condenser and the fan started running backwards, slow start as if it had a bad capacitior, but definatley backwards. I turned it off and back on again and it corrected itself. PSC Motor

  6. #19
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    17,729
    Quote Originally Posted by BuGnLikeAnInSect View Post
    single phase will not run backwards only 3 phase can. if the rpm's look about right, correct the problem with a new fan blade thats meant for the rotation... a little cheaper than a new motor andless work. often most motors the rotation is if you were looking at the butt end of the motor unless it says cwse or ccse that woull be shaft end of the motor. I have run into motors spinning backward such as 9w motors in supermarket evaps, usually can be corrcted by clipping the capacitor wire (which is usually blue) and just having the 120 going to the motors.

    Single phase motors are able to run in the opposite direction according to:

    1) the position of a reversing plug

    2) the condition of the windings and connections

    3) the condition of the cap and the way the three (or four) wires are connected

    In the case above, condition #2 is most likely. It would not be appropriate to install a fan blade for the "new" direction, since it is most likely that the current rotation is not what is on the label.

    After checking connections, if the motor still turn the wrong way, replace the motor.
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







  7. #20
    I couldn't tell you exactly what happened inside your motor but it aint no good no more.
    I have seen this alot on the Florida Heat Pumps in one building I work on they are 460 3 phase units that split out 2 legs and run a 460 split phase blower when these burn out they frquently run backwards. Chang the motor and move on.

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