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Discussion Starter #1 (Edited)
Hello,


This is my first post. I recently tried my hands at replacing the ac fan motor.(After AC person told me the fan wasn't rotating as freely as it should. And motor would probably have to be replaced soon.) I wish I took notes on how the unit sounded/vibrated before doing this.


Long story short. I replaced the motor with proper unit. Turns on. AC is cold. But I'm noticing a little bit of vibration from the motor. And when the unit shuts down I notice a noise as well. This could possible be how it was before. I never paid attention.


I've linked two vidoes 10 seconds each. The shut down noise is easy to hear. The vibration is a bit harder to see. I noticed the link video played in my browser is only 360p. But the video itself is 1080p. You can download it if you want. But even at 360p I think you can kind of notice some vibration. Again, very little.


Is this normal stuff? Should I get it looked at professionally? Thank you.


Here a link to my Google Photo's shared album.


(Apparently I can't add links to first post. So I'll post this as is and then see if I can do a second post with link.)


Update: Seems I can't reply to own post with a link. I get a message saying "You need at least 1 post to post links". Probably for security/spamming reason. Understandable. Anybody know what I need to do to add the link? Sorry, I'm new to posting on forums. Thank you.
 

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Any change to a motor mounting can affect how the noise is transferred to whatever it's attached to.

Did the new fan mount the same way the old one did? If it was end bell mounted with rubber isolation pads at each end of the motor, did you use the old rubber or was new mounting rubber supplied?

Check to see that nothing was accidentally sucked into the blower wheel and throwing it out of balance. That may be where your missing glove is.

If all that checks out, you may be like me, you get so critical of things you work on that you tend to notice things that were always there and think you're the blame. :biggrin2:
 

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Discussion Starter #3
The motor was identical fit/size wise. So it mounted exactly as the old one did. No pads or anything. I really hope it's not abnormal to vibrate a bit. It's not jerky. Just visible vibrating a bit. I'll keep an eye on it. Thanks!
 

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Discussion Starter #5
Link worked! Also added a second vibration video. It's a little longer and closer to camera so you can really see the vibration.(Again you can see it better in 1080p. Videos are short so not that big.) Thanks
 

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Discussion Starter #7
Yeah, a slightly bent fan blade is what I thought it could be. I tried to be careful but my dad did grab the blade when I was trying to take it off the old motor.(To help stabilize it.) I caught him holding it and I told him to let go. He's 70+ and I don't think he held it hard. He said he didn't so I believe him. I visually inspected it and it didn't look bent. All the fans looked the same. But I guess it could be bent so slightly I can't really see it. Maybe I'll take a closer look tomorrow. Thank you!
 

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Motor may be spinning backwards.


If its spinning counter clockwise looking down into the unit, its spinning backwards.
 
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Discussion Starter #9
I know air was being pushed up but I doubled checked. Blades spinning clockwise. Thanks for the suggestion though.
 

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Could be the blades are slightly out of balance.
 
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Stick something down through the grill until it barely touches one of the blades (power off of course) and give it the old poor mans check up for any blade bent out of alignment. Get them all the same and it should be OK.

Seems like it's not only vibrating, it's finding something in the surrounding metal that resonates with it as it passes through a certain speed when spooling up and coasting down.
 

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Discussion Starter #12
That's a great idea using a stick through the grill. I'm out of time for today so I'll have to do it sometime tomorrow. Thank you.
 
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