Motor Noise on Almost New PM 3520b

[Mike Goetzke]

I did some searching but my noise seems different. A non-rhythmic (i.e. not once per rev) noise seems to be coming from the fan end of the motor. Like something loose in the fan end of the motor. I can hear it at below 500 RPM. At 500 and above the fan and other things are louder. I can hear it with the belt disconnected and the motor run or spun by hand. The motor armature spins very freely as I let it coast down without the belt. At first I though it was the fan - almost sounded like fan was loose on the shaft and hitting something every now and then. I went as far as removing the fan and the noise is still there. Since it's under warranty didn't want to tear into anything else yet. Any clues of suggestions? (This noise seemed to just start today)

Edited: After further listening it's stranger than I thought. I can hear a similar noise at the drive end of the motor but they don't seem to be in phase with each other. I was just wondering - could this just be the VFD doing it's thing? I do wear an Airshield Pro all the time so maybe I didn't notice it before.


Thanks,

Mike

[Steve Schlumpf]

No idea at this point but if you can still hear the noise when you spin the motor by hand - then that should rule out the VFD. You have removed the fan, taken the belt off and rotated the motor by hand and the noise is still there... not much left other than bearings or the possibility of something loose within the motor housing.

[Mike Goetzke]

No idea at this point but if you can still hear the noise when you spin the motor by hand - then that should rule out the VFD. You have removed the fan, taken the belt off and rotated the motor by hand and the noise is still there... not much left other than bearings or the possibility of something loose within the motor housing.

You are right Steve the noise it there even w/o power. Guess I need to give Walter Meier a call.

Mike

[Steve Schlumpf]

Seeing as how it is under warranty, I agree.

[Mike Goetzke]

Seeing as how it is under warranty, I agree.

Talked to the tech and let him listen over the phone and he said since I have a 5-year warranty to just use it for a while to see if it goes away or gets worse.

Mike

[Scott Hackler]

I would suspect a bent fan blade fin is contacting the housing. I had something very similar on an exhaust fan on a furnace. I took the cover off and looked for a fin with wear on the edge and slightly bent it until no more clicking noise. Worked great and was easy to do. Al lot easier that sending that heavy dude back for warranty work!

[Steve Schlumpf]

Scott, in his opening statement, Mike said that he went so far as to remove the fan and the noise was still there. I am thinking that there is something loose within the motor housing; debris, something that is getting thrown around when the motor is under power. Course, I haven't heard the noise... so it is just a guess on my part.

[Mike Goetzke]

Scott, in his opening statement, Mike said that he went so far as to remove the fan and the noise was still there. I am thinking that there is something loose within the motor housing; debris, something that is getting thrown around when the motor is under power. Course, I haven't heard the noise... so it is just a guess on my part.

That's what I was hoping for but I tried that. Almost sounds like a diesel engine running (but not that loud). I'm with Steve - seems like something loose (or coming loose) in the motor housing. Guess I can just ride it out since it does have another 4 years of warranty like the technician suggested but on the other hand a $4K machine should run right.

Mike

[James Combs]

Talked to the tech and let him listen over the phone and he said since I have a 5-year warranty to just use it for a while to see if it goes away or gets worse.

Mike

It would be my luck that at 5yrs+1day the motor blows up, locks up, quits or something else "now" out of warranty.

Edit: A noise like that would drive me batty over time, never liked the sound of diesels.

[Thomas Canfield]

You did not mention checking the speed pick up mount. I had mine come loose and thought that there was some bearing or other problem. It turned out to be a loose set screw on the tach pickup mount to shaft.

[Mike Goetzke]

You did not mention checking the speed pick up mount. I had mine come loose and thought that there was some bearing or other problem. It turned out to be a loose set screw on the tach pickup mount to shaft.

I checked it and it in there solid.

[Steve Schlumpf]

Have you blown the motor out with compressed air? Might see or hear something in the process. Personally, I would be tempted to pull the motor and get a closer look as to what is happening. Good luck with everything!

[Mike Goetzke]

Have you blown the motor out with compressed air? Might see or hear something in the process. Personally, I would be tempted to pull the motor and get a closer look as to what is happening. Good luck with everything!

Looks like a totally enclosed motor design. I'm tempted to remove the end housing at the fan end but since it's under warranty I need to resist.

[Jack Mincey]

Try changing the tension of the belt. Had one at the school I taught that made the same sound. I thought it was the fan but ended up going away by changing the tension on the belt some. It would still come and go at times. I felt the long shaft on the motor caused it to flex when the belt was tensioned to much and cause the sound. The old 3520 has a much shorter shaft on the motor.
Jack

[Mike Goetzke]

Try changing the tension of the belt. Had one at the school I taught that made the same sound. I thought it was the fan but ended up going away by changing the tension on the belt some. It would still come and go at times. I felt the long shaft on the motor caused it to flex when the belt was tensioned to much and cause the sound. The old 3520 has a much shorter shaft on the motor.
Jack

Mine makes the noise with the belt off and rotating it by hand.