can I reverse this not-labelled-as-reversible single phase motor?
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  1. #1
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    Default can I reverse this not-labelled-as-reversible single phase motor?

    Looking to reverse this motor, would this just be a matter of taking apart the motor and digging out the correct leads (there are no terminals for them in the connection area) or is it impractical/impossible by design? I can take it apart and bring it to a motor shop to save them the trouble (and me the expense) of taking it apart if the consensus is that locating the correct section of coils would be difficult...img_20190813_151114.jpg

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    Remove the end bell opposite the output shaft.

    Show a pix or two

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    First show the connections. Second, is there a capacitor mounted on it? It may be a repulsion-induction motor, in which there may be a set of brushes under the end bell Doug asked you to remove. They may have two positions for forward and reverse.

    Bill

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    Most AC induction motors CAN be reversed, but the mfr may not have allowed it to be, which they accomplish by not providing you with access to the connections to do it. That may be due to mechanical issues, bearing design, cooling design, etc. etc., you will not likely be able to find out. CAN a motor shop disassemble it and find the right terminals to be able to do that, then assess its suitability to be reversed? Sure, but it will likely cost you more than a replacement reversible motor is going to cost you.

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    I have reversed a single phase motor (starts and runs on the same capacitor) by replacing the capacitor with an equal reactance inductor. The motor ran hotter but that was largely from the fan it was driving moving less air in reverse.

    I have reversed a shaded pole motor by flipping the bell ends and rotor around so the shaft sticks out the other side. You can probably do that with any motor.

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    OK ignore the 4th (red) conductor as that wire is not used (4 conductor cable used for this single phase motor) there IS a terminal 5... motor does have a capacitor. I'll pull the end bell if this info means there still is a possibility...
    Attached Thumbnails Attached Thumbnails img_20190816_100229.jpg   img_20190809_165159-2-.jpg  

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    Are there any more wires under the ones we see?

    Single voltage 230V motors are less likely to be reversible than 120/240, just because of the typical way they are set up as tp the start circuit. It's not impossible, though.

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    no more visible wires. I'll pull it apart next week Kills me as I have 47 other motors here on the shelf, none of which are suitable for this application...

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    Have you looked at the cover plate over the connections. Instructions for reversing are often on its inside. Is there a centrifugal switch? When it starts, after a second is there a click and change of pitch? Is there a similar click as it runs down? It looks like a normal capacitor start motor that is reversable by switching two of the leads with push on terminals.

    Bill

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    3 wires in to the stator coil pack, red/yel/blu, cap, and there is a centrifugal switch & thermal protector. Any ideas? There WAS a sticker on the terminal cover plate, long gone..
    Attached Thumbnails Attached Thumbnails img_20190818_102610.jpg   img_20190818_102637.jpg   img_20190818_102812.jpg  

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    Quote Originally Posted by tomjelly View Post
    3 wires in to the stator coil pack, red/yel/blu, cap, and there is a centrifugal switch & thermal protector. Any ideas? There WAS a sticker on the terminal cover plate, long gone..
    It is definitely reversable, probably by switching the two brown (more or less) wires on the right side of the third picture. Disconnect them and check continuity between them. They should read very low resistance, so low that it may appear a dead short on your multimeter. If so, trade them and insert the plug for an instant. If it jogs in the reverse direction, plug it back in.


    Bill

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    Either the yellow or the blue wire is connected to both the start and the run winding. you will need to cut the thinner wire off of it and bring a 4th wire out of the stator.

    The other end of the start winding is connected to the red wire that goes directly to the capacitor.

    I think the common point of both windings is the yellow wire.

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    OK, separated things a bit more for clarity, I've got numbered wires that go into the stator coil pack as follows from the top down:
    1) red insulated wire from capacitor attaches to 1 coil lead
    2)yellow insulated wire attached to one heavier gauge coil lead
    3) black jumper attaches to 2 coil leads
    4) 2 coil wires connected together
    5) the other end of the black jumper attached to 2 coil leads
    6) 2 coil leads attached together
    7) blue insulated wire (not exposed in the photo- has one heavier gauge coil lead)

    Not sure how to proceed from here, from the above the only 2 heavy gauge coil leads: 1 goes to the yellow and one goes to the blue insulated wires. I tried to add text to my picture but for some reason that picture keeps getting shrunk
    Attached Thumbnails Attached Thumbnails img_20190818_173416.jpg   img_20190818_173416.jpg   img_20190818_182432.jpg  

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    One more time. In the third picture of the first set of pictures, there are two wires that look brown or reddish brown with push on terminals on the right side of the picture. As they lay there, they are at right angles to each other. Pull the terminals off and check continuity between them and to the other wires. If they show continuity to each other and not to anything else, they are the starting winding. Put it back together and switch them.

    Bill

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    If you are referring to the brownish wire that goes to the centrifugal switch (not the red one) and the lighter color almost dirty white wire at 90 degrees to it with a little bit of a diagonal black thin line on it there is no continuity between those 2 wires

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    This may be one of those motors with the start winding connected to the midpoint of the run winding. In which case the start cap will be 110 vac rated and you can reverse it by simply swapping the yellow and blue wires, or by moving the connection point for the start switch from line 1 to line 2.

    The reason they do this is so you can make a dual voltage motor with 6 or 5 wires instead of 8, which would be required for a dual voltage start and run winding.

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    If that was the case wouldn't there be 2 stator coil wires attached to either the yellow or blue wire? each is attached to only one (heavier gauge than the others) stator coil wire; does that mean the yellow and blue is for each end of the start winding?

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    No the yellow and blue wires are at each end of the run winding.

    One of those other splices should join the midpoint of the run winding with the start winding, which appears to be 2 smaller wires wound in parallel

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    OK, got it going, I had to draw a schematic for my meager brain to understand what was going on. I realize the start and run windings had to be reversed from their old position in relation to one another. Here's what was there and what I ended up with, it runs in the desired direction, stays cool and doesn't make any bad noises, does this look OK and am I running on the run winding and not the start winding??:
    Attached Thumbnails Attached Thumbnails img_20190822_162118.jpg  

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    If the centrifugal switch is working, you can't be running on the start winding, ergo you have to be on run. Johansen is correct.

    Bill


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