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Help w/ Single Phase AC Motor wiring? (not HW)

  1. Feb 11, 2012 #1
    Hey all. I have an old garage door opener motor. Its a 1/3 HP, 1000 RPM, 115 volt, 3.6 amp, AC Motor (Am I correct in thinking its single phase?). I'm attempting to motorize a grain mill that I have in the kitchen. (the faster I can grind the wheat the faster my wife can make homemade bread right? ;)

    I am following a similar design as this guy:
    http://sdcollins.home.mindspring.com/GrainMill.html [Broken]

    The Motor is a bit older and the wires had a good layer of dirt over them when I pulled it out of the garage door opener frame. However with some cleaning up I've exposed 4 wires:

    White, Green, Red, Brown (They are unmarked other then color and enter the motor casing by the same hole)(See attached diagram)

    I also have salvaged the dual capacitor which has a yellow wire(attaching the two together), a blue wire attached to one, and a red wire attached to the other. (See attached diagram) Also, the capacitors are encased in plastic, not metal, and therefore do not need to be grounded???

    GOAL: Correctly wire the motor and the capacitors to a normal three pronged 120v plug, with a simple switch installed. I'd also prefer the motor to spin clockwise.

    I've searched the internet and spoken with friends but haven't been able to figure it out.
    Any pointers would be appreciated!


    Attached Files:

    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Feb 11, 2012 #2


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    Do the capacitors have a value marked on them that you can see?
  4. Feb 11, 2012 #3

    80-96 MFD
    220 VAC 60 CPS
  5. Feb 11, 2012 #4


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    I will assume that the green wire coming from your motor is a ground wire. You should verify it by using a continuity meter and checking to see if it is connected to the chassis of the motor. Most garage door opener motors are not meant to be run for long periods of time. They will overheat. So this could likely be pointless.
  6. Feb 11, 2012 #5

    jim hardy

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    The guys here can figure this out but they need some more information...
    and it's a little hard to ask the questions succinctly.

    so here goes -

    do you have a multimeter that can read ohms? You can get one for $9.95 at Walmart.

    could you make a matrix with all these ohm measurements in it?
    the ohm readings should be one of three: zero, or infinite or just a few ohms- less than ten.

    Difference between start and run winding ohms will be not very much. so be meticulous and use lowest ohm scale.
    Before starting, check that meter reads zero with leads shorted together.

    ....Ohm Readings:.........................
    green to motor frame __ohms (hopefully zero)
    red to motor frame (hopefully infinite)
    brown to motor frame "
    white to motor frame
    red to brown
    red to white
    brown to white

    red to green
    white to green
    brown to green

    ..end readings .............................

    lastly is there a switch on the motor that's actuated when the shaft gets to speed? Often this is internal to motor, look carefully.
    A plastic capacitor is usually only for starting so there should be a switch, unless those caps are labelled "Motor Run". I have been unable to find that GE part number perhaps it's a special for the garage door company.

    If you find the switch and can actuate it with a small dowel or something, see which of above ohm readings it changes. Repeat them all and add a second set of readings "with switch manually acuated"

    another hint - when your ohm-meter is reading between two wires, twirl the motor shaft a little with your fingers.
    If the two wires have a winding between them the ohmeter will deflect momentarily as you start to spin the shaft.
    If the two wires just go into motor and are connected to same point, that is there's no winding between them, you won't see that brief meter deflection.

    here's a link with a guess by a motor guy - see 'e bodine' and be aware he was guessing.

    Your ohm readings will be a big help.
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