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Checking windings and stator


Robert Kennedy

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Robert I am confused, you said it did spin up when you got it back, but the issue is now showing up after assembly . how did you test it before assembly?  i have had the experience in the past where the rear spacer on a motor disintegrated allowing the shaft and armature to move too far back and it would lock up. i added a spacer to recenter the armature in the coils and it works fine... i am wondering 2 things, is the back end of the shaft into the oscillator gear box jamming up with something in the oscillator box when power is added?  when you power the fan up does the blade, shaft etc all move backwards or frontwards following the magnetic  field? ...dont be insulted when i ask this because i have done this myself...is the stator facing the right way? i have done this!  lane is right for you to check for play in the bearings , but i am still confused as to how it ran ok when first direct wired it ....hmmmmmmmm

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Ohhh trust me Tom, I know where you're coming from for sure. The first thing I did when I got the stator home was to put the shaft part into the stator then direct wired it with the new plug cord that I was going to eventually use on the fan. But before I plugged it in,, I tested the ohms and got a strong 39.7 ohms so I knew I was good to go and sure enough it spun freely so I started the process of putting everything back together. Let me ask you all a question before I go any further, when you say "bearings" are you referring to the brass nose piece that the blade shaft slides through? because that's the only thing that I can see that would be a bearing......if so, can it be replaced and what would the process be to get it replaced. I have a box of fiber washers that I just bought from Harbor Freight so I will find the right sized washers to add to the front and back of the shafts.....it currently has nothing in place. Tom, when you say spacer are you referring to a fiber washer? Again, please forgive my ignorance here as I am still quite new to the fan world. You all have been a great help in solving a lot of the problems that I have encountered. Answering your question about shaft movement, it doesn't move at all either way.....it literally can't be moved after I plug it in.....it's like it's frozen, then when I unplug it, I can move it freely back and forth and also spin it. I haven't really "gone there" in regards to the stator facing the right way. the 2 lead wires are on what I call the lower back side so the leads can be pulled through the lead wire hole on the back cover. Unless that's not where it is supposed to be......but to me it only makes since to have the leads facing down and on the left side where the factory hole is.

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Hi Robert,

The reason that I asked you for a picture of the back of the motor housing and a picture of the blade is so that I could make the stator leads exit where they should and that the motor rotation would be correct.

 

There is almost certainly something wrong with the bearings, either wear or alignment that is giving you problems. You may need to look further into your rotor centering in the stator, both axially and laterally (concentricity and end play) to see how the rotor becomes bound when power is applied. The rotor may be jamming against either end of the housing, or it may be getting "sucked" into the stator. It doesn't take much out of tolerance to cause issues like this. Usually it is a fairly simple fix, just bumping the end bells around as you tighten the screws may provide the "adjustment" needed.

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When bearings are worn badly, the rotor is no longer centered in the electromagnetic field from the stator, and the rotor will magnetically "bond" to the side of the stator it's closer to. In most cases it's the bottom because gravity causes the bottom to wear egg-shaped.  

Trying to run it upside down lets the rotor shaft run on the side of the bearing that's not worn. Often they run just fine that way.  

With the power off, have you tried to lift the blade (and therefore the rotor shaft) to see if the bearing has slop in it????

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Not yet but I will check it later when I get home. Where might I get a bearing for it should it need to be replaced?

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OK ROBERT NOW I GET IT WHEN YOU TESTED YOUR STATOR YOU DIDNT ACTUALLY RUN IT JUST TESTED FOR POWER. THE SPACER I REFER TO IS THE FIBER OR PHENOLIC OR ALLOY WASHERS . AS THE GUYS SAY IF THE ARMATURE DOESNT CENTER IT CAN FAIL TO RUN. YOU SAID WHEN THERE IS NO POWER YOU CAN MOVE THE SHAFT BACK AND FORTH ...HOW FAR? .  ALSO IF YOU PULLED THE SHAFT FORWARD OR PUSHED IT BACKWARDS TO THE LIMIT OF THE "PLAY" THEN POWER IT UP HOW FAR FRONT OR BACK DOES IT "JUMP" TO THE LOCK POSITION? I AGREE THAT YOUR BEARINGS/BUSHINGS MIGHT BE WORN OR LOOSE IN THE FRONT BELL, AND THE REAR OSCILLATOR BOX MIGHT NEED  JUST A LITTLE ADJUSTMENT (ALSO KNOWN AS PLAYING WITH) TO LINE UP THE ARMATURE IN THE RIGHT SPOT SO IT DOESNT LOCK... WHERE ARE YOU LOCATED ? YOU MIGHT FIND A LOCAL REGIONAL EVENT NEAR YOU WHERE YOU CAN GET SOME TECH HELP...OR AN AFCA MEMBER NEARBY WHO CAN HELP?

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I live in Ponca City Oklahoma which is in far Northern Oklahoma so it would be exciting to find an event or a fellow AFCA member to glean from. I'm a bit busy right now at work so I probably won't work on it until this Saturday. I am so grateful for all the help that I get from you guys......I would just give up if it weren't for you guys.

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