Servo motor noise

[Dwight]

OK . . . go out into the shop . . . get the longest . . . skinniest screw driver you can find . . . 

OR . . . if you have something with a plastic handle and has a long hard rod coming out of it . .  .

Turn on the motor at it's slowest speed  . . . put the metal end of the screwdriver or whatever else you have . . . and put the handle end up to the little flap that covers your ear canal . . .  push that flap against your head . . . and listen.  

You want to stick the end of that screwdriver (or other tool) just above where the shaft comes out of the motor . . . and on the backside at the approximate same place.

In the Navy . . . this is how we tested every bearing on the ship . . . and how we found out if one was failing.  

I'm going to take a shot in the dark and say you have a good bearing . . . but it was not greased from the factory . . . something that happens from time to time . . .  and when they run dry . . .  they make a very similar sound.

Just wish I had a dollar for every bearing I've listened to since I started that back in 1964 . . . 

May God bless,

Dwight

Edited October 13, 2023 by Dwight

[RockyAussie]

9 hours ago, Hidden said:

Just took apart the servo, cleaned whatever I could and put it back together again. Same noise

One thing to note is that the sound you hear is in sync with the machine (one CHWUNK per stitch). I'm not sure if that matters.

I came across a servo that looks like that one recently doing the same thing. We ordered in a new motor to replace it but before doing that we took the motor off to see if we could find anything. I think there must be a magnet thing inside because when we gave it a shake to start with there was a rattle noise but then it stopped rattling. We thought well lets give it another try on the machine and it then went fine. Its been going strong now for maybe 3 months without any noise. Maybe the sudden stop they do sometimes shook the magnet loose, I don't know. He now has a backup motor if needed now but means he would have to drill some new table mounting holes etc which is why we tried the other old one first.

[Constabulary]

That sound IMO is not an issue. I have two JACK Servos with 750W and the earlier one is running since.... have to guess ... since 2014. They both make this sound. I´m not sure but I think more 750w motors make this sound than the 550w motors but I´m not 100% sure.

[Hidden]

I took apart the servo again this morning for cleaning, here's some pictures:

 

The rough patch on the axle is suspicious, but I don't know what causes it, as it isn't actually in contact with anything when the motor is assembled. It might not be a problem at all. The middle part is magnetic, which makes it a real pain to get any small metal bits off of it. I also found that rough spot on whatever you call the thing on the right ^, cleaned that up but then realized that it doesn't actually spin :') goes to show the machining on these things isn't particularly top notch, though. I also checked the bearings and they are lubricated, spin okay and don't make any noise.

Here's a picture of the 50mm pulley, it does sorta-kinda look off-center a little bit (especially the first pic)

However, more importantly, I just learned that these pulleys are supposed to use a 3L belt. The machine I bought came with an SPZ belt, which is the same width but taller. I bought an SPZ belt of the same size to replace it. The plastic part that can be screwed over the pulley also had some shavings of the old belt in it, which I found a little suspicious.

Guess I'll order a 3L belt to see if that works better, maybe a new 45 or 50mm pulley as well. Or a polyurethane belt. Thanks all for your help so far!

- Hidde

 

Edited October 13, 2023 by Hidden

[CowboyBob]

FWIW,Alot of the first servos we got in 15 yrs ago used to be pretty loud some in the same shipment were louder than others,they claimed it had something to do that they had uneven # of windings in the coils as time progressed they seemed to get quieter.We only use the brush type now & they all seem to be real quiet.

[kgg]

 

2 hours ago, Hidden said:

I took apart the servo again this morning for cleaning, here's some pictures:

I would send back the motor for a refund as the cover has damaged the bearing face as can be seen in your photo's. I would not accept a replacement as there is a problem with their cover mold and you are more then likely just going to have the same problem. The problem with keeping that motor is it will never run true and is going to fail, when who knows.

kgg

[Hidden]

1 hour ago, kgg said:

 

I would send back the motor for a refund as the cover has damaged the bearing face as can be seen in your photo's. I would not accept a replacement as there is a problem with their cover mold and you are more then likely just going to have the same problem. The problem with keeping that motor is it will never run true and is going to fail, when who knows.

kgg

Apologies, what is the bearing face? Is that one of my circled parts?

[kgg]

2 minutes ago, Hidden said:

Apologies, what is the bearing face? Is that one of my circled parts?

The circled part in photo #2.

kgg

[GerryR]

The circled part in photo #2 shouldn't be touching anything on the bearing.  The bearing sits in the machine bore in that housing.  If I was into the motor that far, I would remove that flash (lower circled part in photo #2) with a cutter of file.  Check the bearings while the rotor is out of the housing; they should be smooth as butter while applying some pressure on them as you rotate them.  If they feel "gritty" or there seems to be a "bump" while rotating, then it is a bearing problem, otherwise they are good to go.  The rough spot on the rotor shaft, top circled part in photo #2, isn't touching anything and should be of no concern.  Just my $0.02

[fibersport]

I agree that the circled part isn't the issue, that is what the bore of the bearing sits on, if the bearing is turning on that there's a big problem. Also, I don't think the flash on that end cap or end bell is causing it, look at the distance from the bearing to the armature.