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Oliver Overgaard
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Hello everyone,
I didn't even know these types of fans existed until today when I was brought one to fix due to an "odd" noise, sounds like excessive play in a bearing to me, like it's kind of "Off Kilter" 

So not knowing much I figured I'd be like any of the 100's of commercial induction motors I've taken apart in my work as a technician but now I'm realizing this is a bit of a different beast and I'm going to need some help, so here I am.

I have a 77646AM Emerson Electric, supposedly from the 1940's, I'll post up some pictures but it looks a lot like this. Actually, looks pretty much exactly like this, even the cage is the same.

I'm having trouble getting the fan blade off, I've read through what I could find and tried the 1/4"-20 trick but it didn't do it, tried jamming a piece into one of the holes in the rotor, a piece of aluminum, 2 different punches, some all thread and tried unscrewing the blade, nothing's working and I don't want to damage it.

I also cut off the wiring to the fan motor thinking the black white and green would be obvious........ Turns out it's miltiple speed so now I don't know which goes where, I figured I can probably measure winding to winding and figure out which is which, but I'd have to know what the different speeds should be.

Any help you guys can throw my way would be much appreciated.

Attached Image (viewed 132 times):

Emerson Disassembly_1small.jpg

Steven P Dempsey
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there is a 2 digit date code in lower right of the motor tag, add 20 for year made, 25 = 1955, etc - - also, the old style capacitor (like a a sardine can) should be replaced with a solid state (2.5 MFD) cap

The blade is a whole other story . . Must lock rotor & unscrew CLOCKWISE. I use a regular philips screwdriver.There is only one hole that locks the rotor, windings can be damaged

Steven P Dempsey
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this is for a 77648 (16") but should work

Oliver Overgaard
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You good sir are a life saver, thank you so much.

I've tried jamming the rotor multiple ways but I cannot get the blade to spin, I found some older articles on this particular style of fan which leads me to think that perhaps torching the shaft may help?

Oliver Overgaard
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Another point of concern is the cap in there is a 3.5 or 3.0 MF. I read in one of these threads that the capacitor has to be pretty exact for the unit to work properly.

The original complaint was noise, I'm wondering if it had anything to do with it.

Steven P Dempsey
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I read that one slightly under may the better, but check on that science. I have been using 2.5MFD

Oliver Overgaard
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Okay, so what would be your first guess for a "noise" complaint, no idea what the maintenance was on it, someone recently did electrical work on it, not sure who but they put a new capacitor in it for sure.

Can I get parts for this fan still?

Steven P Dempsey
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Put this in an Emerson Government fan (16"), works great.


Attached Image (viewed 86 times):

Run Capacitors.jpg

Oliver Overgaard
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So if there's a 3 MF cap in it, should I put in a 2.5 MF?

Steven P Dempsey
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I need to check, I recall seeing that - - & I have been using the 2.5s, in Pedestals & desk fans - - since they are "run" capacitors, it may slow down the top speed some (less noise & vibration)

Oliver Overgaard
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Okay, much appreciated thank you.

Marce Clark
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I have been using 2.5 mfd caps in Emersons as well and the work great.I wouldn't put anything bigger than a 3.0 in it.



Marce

Andrew Block
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I'm not sure if that is the later model with the more skeletal motor or not, but I don't think those you can use the screw hole to lock the rotor.

That looks to be in excellent shape, I'd be VERY careful about torching it. What you're attempting to do is loosen the oil that has congealed in the leather washer.

You need the diagram for how to rethread the headwire down the pipe. It has to go in a very specific way or the fan will jam being raised or lowered. I don't really care to work on those.

Oliver Overgaard
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Thank you guys, I have managed to get it apart without torching it, just really had to lock the rotor down.

Cleaned the rotor and sprayed the inside with electrical contact cleaner, cleaned the groove in the rotor centerway so I think it's fine to go back together now.

The rotor did not want to come off, so that took a bit of work but now it slides on and off really smooth.

Looks like the original cord was still on there but had been patched in multiple places, so I just replaced it. I see what you are saying about the headwire.

Does anyone have that Diagram?

Oliver Overgaard
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Well guys, turned out well in the end.

Put it back together, used a fat cord to go between the base and the motor, slides up and down well.

Motor is completely quiet, cleaned the rotating mechanism gearbox and put fresh white lithium in it, fixed it so it would actually turn 180* so everything is well.

Thank you guys so much for your help.


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